[Assi]

At post #416 above I put photos of the actuator forks position in 2Hi /4Hi / 4Low.
I am adding here photos of the positions of the “rings” inside the PTU.

This is 2Hi.

This is 4Hi.

This is 4Low.

Note, when installing back the Actuator, it is better to put the PTU in 2Hi position – as you can see in the 4Hi photo above the right ring is close to the right edge so there is not much room to get the fork inside.

 

[Flechtight]

At post #416 above I put photos of the actuator forks position in 2Hi /4Hi / 4Low.
I am adding here photos of the positions of the “rings” inside the PTU.

View attachment 239789
This is 2Hi.

View attachment 239790
This is 4Hi.

View attachment 239791
This is 4Low.

Note, when installing back the Actuator, it is better to put the PTU in 2Hi position – as you can see in the 4Hi photo above the right ring is close to the right edge so there is not much room to get the fork inside.

Perfect pic, I’m getting ready to refresh my PTU oil after the drain plug install. Definitely going to utilize the breather for my refill.

 

[Assi]

FIXED.
(been driving for several days for several hours – so hopefully it is done).

At post #458 above I wrote about the last BOOM I had.
So, I took the PTU out, opened it, but didn’t see anything broken with a visual inspection. Also, the oil wasn’t silvery or had shining dots.
For investigation purposes, I cleared the faults that could be cleared, connected the Actuator back, and started the engine (PTU out, only Actuator connected, Driveshaft and Half Shaft also out – all the rest, electricity, Exhaust and all, connected).

This is what I got:

• The wheels still didn’t turn in Drive or Reverse.
• When I tried to put in Parking I got again the grinding noises.
• At one point I got stuck in Neutral (or Drive, not sure) and couldn’t move the shifter and also couldn’t turn off the engine, since I wasn’t in Parking (after playing with the faults for a minute it was released - but I think it wasn’t because of the faults but because of the minute).
• Got messages in the instrument panel display “Service Park Brake”, and “Service Transmission To Shift Vehicle Must Be Stopped”.
• And numerous faults (something like 15 faults) in various modules.

At this point I thought of trying to fix or replace the Transmission, made some calls to see the options – very expensive comparing to the value of the Jeep. I also was looking for PTU in eBay (it is around 1K$ remanufactured).

Then I started to think...
There were 4 issues, Transmission, PTU, Park Brake and faults.

Faults - the faults were mostly about Transmission, PTU and Brake, but there were also some other faults. But, as I seen happening before, the other faults could be related to the main faults (derived from a module that can’t connect to a module that has a problem or so), so I decide to put aside and ignore the other faults.

Park Brake – I was reading about the fault messages and of grinding noises in general, and I got to this theory: usually you drive, stop, and shift to Parking. If you try to shift to Parking while moving, you will get grinding noise.
In my Jeep case, the wheels weren’t turning when I was on Drive, but the transmission inside probably was turning (otherwise you wouldn’t get grinding noise – I guess). So, when I shifted the transmission to Parking, which looked normal since the wheels weren’t turning, in my Jeep case the transmission actually was turning, so I got the grinding noise.
It also explains why I didn’t get grinding noises always, since it depends whether I moved to Parking from Drive or from resting in Neutral.

So the theory was that there isn’t a problem with the Park Brake but it is a results of the problem with the Transmission that doesn’t turn the wheels.

Transmission – the transmission doesn’t turn the wheels in Drive or Reverse. As I wrote in Post #458, there were these relevant faults:

• Under general fault: P215C “Output shaft speed – wheel speed correlation”
• Under Transmission this fault: P1720 “Output speed sensor/wheel speed rationality”.

At the YouTube that I attached at that post, he had a different problem than what I have in my PTU, but he got the same above faults, and also no forward or reverse. When he fixed the PTU, the transmission was working again.

My theory is that these faults cause the transmission to disconnect from the wheels. The transmission compares the speed that he has in his shaft (or somewhere) to the speeds sensors on the wheels. When it detects that the speeds are different, he raises these faults and, this is the theory, disconnects the transmission from the wheels.

So what I thought of was to connect a good PTU, and see what happens. If the theory is right, then the transmission will be working again (now that it will compare the speeds and see that all is good). And if it is still not working, or making metal noises then I know that the transmission needs to be fixed.

PTU – I wanted to get a new PTU, but before, I wanted to inspect my old PTU better. I emptied all the oil, inspected it, and there were no debris.
Then I deiced to understand the PTU rings poisons better (see the post above). I moved the rings according the actuator forks for 2Hi/4Hi/4Low, and I turned the shafts to check. I played with it for hours… and then I realizes, it doesn’t look like there is a physical problem with the PTU. There was some free movement in the shafts, but maybe it is normal, and anyway, even if it is not normal it will probably just cause noises or vibrations but will be good enough for connecting and testing the Transmission.
So I decided to fill oil and put the actuator back. It was on 4Hi so I moved it manually to 2Hi. But then I wanted to verify that it is on 2Hi, so I connected the actuator only, turned the ignition on (not running the engine) and reading the status (AlfaOBD), it was on 2Hi.
Since I was already connected, I couldn’t resist and using AlfaOBD I moved the forks to 4Hi, 4Low and back to 2HI. It moved nicely, and even sounded more vigorous than the old motor…

I installed the PTU and everything back to the Jeep and checked.

All was working.

Even shifting In and Out of 4Low now takes only a second (in the past it used to take some time to shift), I guess it is the new Motor (maybe also the clean oil).

I don’t know what the metal noise was. Maybe it was the PTU stuck, or maybe the noise of the Transmission disconnecting from the wheels.

The problem, was, I think, guess, that when I put the Actuator back, the forks weren’t in the right place.
The first two times when I put the Actuator back, I checked very carefully, making sure. This time, it was already evening, and more excuses, and I did put one side of the forks in the right place, on the “rings rails”, and I was careful, but maybe when I pushed it in it slipped. There was something that didn’t feel right. And also, when I put the Driveshaft back and turned it, I could hear some slight rattle noise in the PTU, but I thought that probably it is ok, and really didn’t want to take the PTU down again.
So now, I practiced, for hours, putting back the Actuator. Finding the right angle so I can look inside it to see that it is going to the right place, and learning the feeling of it sliding into the right place. And also turning the shafts checking that there is no rattle.

That’s it, hopefully.

 

[robotkid410]

What size is the ptu drain/fill plug and RDM to get them lose?

 

[rumrunner]

What size is the ptu drain/fill plug and RDM to get them lose?

I think a standard 3/8” extension fits there are some threads w that detail if you search around

 

[Gary Kline]

@rumrunner's got it. (3/8 ratchet head) Depending on the length of your ratchet/extension, you may need a swivel or wobble.

 

[robotkid410]

@rumrunner's got it. (3/8 ratchet head) Depending on the length of your ratchet/extension, you may need a swivel or wobble.

I appreciate it guys, I tried searching the forums, but only found the size for the heat shield bolts

View attachment 243281

 

[robotkid410]

HI @speedbrake ,

Responses in green bold:

What about the Transmission ATF? Is that not atf red in our 9 speeds?

The fluid in our 9ZF transmissions is special Mopar 8 & 9 Speed Transmission Fluid (part # 68218925AB) made for ZF transmissions (9 speed in the Cherokee, 8 speed in the Wrangler, Grand Cherokee etc.). My recommendation, only buy the MOPAR brand, don't chance it with any other. Out of the bottle it's a clear/greenish tinged fluid completely different than the average red Dextron II-type transmission fluids most of us are familiar with growing up (or at least as my kids refer to it, the "old tyme days" that I grew up in when the world was still in black and white, there was no such thing as the 'Internet' and the wheel and fire had yet to be invented)

View attachment 222488​

​

A pic of that weep hole (with location/context) would be super helpful.


Unfortunately, I've never seen it myself (I haven't had to take out my PTU) but it's described as being between the PTU and Transaxle. Note, I left out one important detail... the service manual states the weep hole is only for 2 speed AD units (AD2 / AD2 w/ rear locker (TH) ) so for those with an AD1, this may not apply.

Using the screenshot below as a guide, I've marked "FWD" as the orientation to the forward end of the vehicle.

1. The green arrow in the back is the rear motor mount.
2. The yellow arrow is the transaxle (to which the PTU is bolted)
3. The bolts holding the PTU to transaxle are in the #1 circle and the #2 circle is the PTU itself

So I would assume that if fluid is leaking from the weep hole, it must present itself somewhere within the white-boxed area.

View attachment 222490​

​

​

Agree. Never done that before. Could someone vector me in to find the fill plug for the PTU? I’ve read there’s no drain plug on the PTU, just the fill. A pic of that fill plug would be very helpful.

1. The fill plug is behind a heat shield on the PTU. To access, remove the heat shield bolts (#2 on screenshot below) that hold the heat shield on (#1 on the screenshot).
View attachment 222492

2. The fill plug is on the passenger side of the PTU. It has a 3/8" socket hole in it you can use your socket ratchet to unscrew.
View attachment 222493

3. This shot is just extra to visualize the fluid inside the PTU. See the red lines I added. This is the fluid bath that the gears rotate in. The fill level is to the bottom of the fill plug.

To me, it's hard to wrap my head around a fluid leak coming from, say, the passenger side half shaft seal or the seal on the actuator at the top since I would think gear oil only sloshes into these areas- they're not bathed in it like the lower part of the case seal or the rear drive shaft seal is but, I'm not the engineer who designed it so they know best (although to all the folks who have had to replace their PTU's would probably debate that last sentence ;-)
View attachment 222494



4. if you decide to pump out your old fluid and/or top off what's in there, if you don't have a pump already, I use a cheep $7 HF special. Works fine and it's cheap.
View attachment 222491

5. Fill specs for the AD1 and AD2's are below. You can get the fluid at any dealership. This fluid is also available 3rd party (Mobil 1, AMSoil etc) so your decision. Many of us like to stay with the MOPAR brand since it's OEM but many also prefer the others. Your choice. (note, if you ever drain and fill your REAR drive module (RDM), there's a different viscosity for that and that one is only available in the MOPAR brand. Recommend don't use any other back there.)

There's also a torque spec (see screenshot at bottom) though most of us I assume just close until it feels tight.

View attachment 222496
View attachment 222497
View attachment 222495

HI @speedbrake ,

Responses in green bold:

What about the Transmission ATF? Is that not atf red in our 9 speeds?

The fluid in our 9ZF transmissions is special Mopar 8 & 9 Speed Transmission Fluid (part # 68218925AB) made for ZF transmissions (9 speed in the Cherokee, 8 speed in the Wrangler, Grand Cherokee etc.). My recommendation, only buy the MOPAR brand, don't chance it with any other. Out of the bottle it's a clear/greenish tinged fluid completely different than the average red Dextron II-type transmission fluids most of us are familiar with growing up (or at least as my kids refer to it, the "old tyme days" that I grew up in when the world was still in black and white, there was no such thing as the 'Internet' and the wheel and fire had yet to be invented)

View attachment 222488​

​

A pic of that weep hole (with location/context) would be super helpful.


Unfortunately, I've never seen it myself (I haven't had to take out my PTU) but it's described as being between the PTU and Transaxle. Note, I left out one important detail... the service manual states the weep hole is only for 2 speed AD units (AD2 / AD2 w/ rear locker (TH) ) so for those with an AD1, this may not apply.

Using the screenshot below as a guide, I've marked "FWD" as the orientation to the forward end of the vehicle.

1. The green arrow in the back is the rear motor mount.
2. The yellow arrow is the transaxle (to which the PTU is bolted)
3. The bolts holding the PTU to transaxle are in the #1 circle and the #2 circle is the PTU itself

So I would assume that if fluid is leaking from the weep hole, it must present itself somewhere within the white-boxed area.

View attachment 222490​

​

​

Agree. Never done that before. Could someone vector me in to find the fill plug for the PTU? I’ve read there’s no drain plug on the PTU, just the fill. A pic of that fill plug would be very helpful.

1. The fill plug is behind a heat shield on the PTU. To access, remove the heat shield bolts (#2 on screenshot below) that hold the heat shield on (#1 on the screenshot).
View attachment 222492

2. The fill plug is on the passenger side of the PTU. It has a 3/8" socket hole in it you can use your socket ratchet to unscrew.
View attachment 222493

3. This shot is just extra to visualize the fluid inside the PTU. See the red lines I added. This is the fluid bath that the gears rotate in. The fill level is to the bottom of the fill plug.

To me, it's hard to wrap my head around a fluid leak coming from, say, the passenger side half shaft seal or the seal on the actuator at the top since I would think gear oil only sloshes into these areas- they're not bathed in it like the lower part of the case seal or the rear drive shaft seal is but, I'm not the engineer who designed it so they know best (although to all the folks who have had to replace their PTU's would probably debate that last sentence ;-)
View attachment 222494



4. if you decide to pump out your old fluid and/or top off what's in there, if you don't have a pump already, I use a cheep $7 HF special. Works fine and it's cheap.
View attachment 222491

5. Fill specs for the AD1 and AD2's are below. You can get the fluid at any dealership. This fluid is also available 3rd party (Mobil 1, AMSoil etc) so your decision. Many of us like to stay with the MOPAR brand since it's OEM but many also prefer the others. Your choice. (note, if you ever drain and fill your REAR drive module (RDM), there's a different viscosity for that and that one is only available in the MOPAR brand. Recommend don't use any other back there.)

There's also a torque spec (see screenshot at bottom) though most of us I assume just close until it feels tight.

View attachment 222496
View attachment 222497
View attachment 222495

I've been using Vavoline Extended Protection, ZF 6,8 and 9 Approved. came out last year, i just changed it about 10K miles ago with no issues. I personally think it protects better then Mopar

 

[Tico007]

FIXED.
(been driving for several days for several hours – so hopefully it is done).

At post #458 above I wrote about the last BOOM I had.
So, I took the PTU out, opened it, but didn’t see anything broken with a visual inspection. Also, the oil wasn’t silvery or had shining dots.
For investigation purposes, I cleared the faults that could be cleared, connected the Actuator back, and started the engine (PTU out, only Actuator connected, Driveshaft and Half Shaft also out – all the rest, electricity, Exhaust and all, connected).

This is what I got:

• The wheels still didn’t turn in Drive or Reverse.
• When I tried to put in Parking I got again the grinding noises.
• At one point I got stuck in Neutral (or Drive, not sure) and couldn’t move the shifter and also couldn’t turn off the engine, since I wasn’t in Parking (after playing with the faults for a minute it was released - but I think it wasn’t because of the faults but because of the minute).
• Got messages in the instrument panel display “Service Park Brake”, and “Service Transmission To Shift Vehicle Must Be Stopped”.
• And numerous faults (something like 15 faults) in various modules.

At this point I thought of trying to fix or replace the Transmission, made some calls to see the options – very expensive comparing to the value of the Jeep. I also was looking for PTU in eBay (it is around 1K$ remanufactured).

Then I started to think...
There were 4 issues, Transmission, PTU, Park Brake and faults.

Faults - the faults were mostly about Transmission, PTU and Brake, but there were also some other faults. But, as I seen happening before, the other faults could be related to the main faults (derived from a module that can’t connect to a module that has a problem or so), so I decide to put aside and ignore the other faults.

Park Brake – I was reading about the fault messages and of grinding noises in general, and I got to this theory: usually you drive, stop, and shift to Parking. If you try to shift to Parking while moving, you will get grinding noise.
In my Jeep case, the wheels weren’t turning when I was on Drive, but the transmission inside probably was turning (otherwise you wouldn’t get grinding noise – I guess). So, when I shifted the transmission to Parking, which looked normal since the wheels weren’t turning, in my Jeep case the transmission actually was turning, so I got the grinding noise.
It also explains why I didn’t get grinding noises always, since it depends whether I moved to Parking from Drive or from resting in Neutral.

So the theory was that there isn’t a problem with the Park Brake but it is a results of the problem with the Transmission that doesn’t turn the wheels.

Transmission – the transmission doesn’t turn the wheels in Drive or Reverse. As I wrote in Post #458, there were these relevant faults:

• Under general fault: P215C “Output shaft speed – wheel speed correlation”
• Under Transmission this fault: P1720 “Output speed sensor/wheel speed rationality”.

At the YouTube that I attached at that post, he had a different problem than what I have in my PTU, but he got the same above faults, and also no forward or reverse. When he fixed the PTU, the transmission was working again.

My theory is that these faults cause the transmission to disconnect from the wheels. The transmission compares the speed that he has in his shaft (or somewhere) to the speeds sensors on the wheels. When it detects that the speeds are different, he raises these faults and, this is the theory, disconnects the transmission from the wheels.

So what I thought of was to connect a good PTU, and see what happens. If the theory is right, then the transmission will be working again (now that it will compare the speeds and see that all is good). And if it is still not working, or making metal noises then I know that the transmission needs to be fixed.

PTU – I wanted to get a new PTU, but before, I wanted to inspect my old PTU better. I emptied all the oil, inspected it, and there were no debris.
Then I deiced to understand the PTU rings poisons better (see the post above). I moved the rings according the actuator forks for 2Hi/4Hi/4Low, and I turned the shafts to check. I played with it for hours… and then I realizes, it doesn’t look like there is a physical problem with the PTU. There was some free movement in the shafts, but maybe it is normal, and anyway, even if it is not normal it will probably just cause noises or vibrations but will be good enough for connecting and testing the Transmission.
So I decided to fill oil and put the actuator back. It was on 4Hi so I moved it manually to 2Hi. But then I wanted to verify that it is on 2Hi, so I connected the actuator only, turned the ignition on (not running the engine) and reading the status (AlfaOBD), it was on 2Hi.
Since I was already connected, I couldn’t resist and using AlfaOBD I moved the forks to 4Hi, 4Low and back to 2HI. It moved nicely, and even sounded more vigorous than the old motor…

I installed the PTU and everything back to the Jeep and checked.

All was working.

Even shifting In and Out of 4Low now takes only a second (in the past it used to take some time to shift), I guess it is the new Motor (maybe also the clean oil).

I don’t know what the metal noise was. Maybe it was the PTU stuck, or maybe the noise of the Transmission disconnecting from the wheels.

The problem, was, I think, guess, that when I put the Actuator back, the forks weren’t in the right place.
The first two times when I put the Actuator back, I checked very carefully, making sure. This time, it was already evening, and more excuses, and I did put one side of the forks in the right place, on the “rings rails”, and I was careful, but maybe when I pushed it in it slipped. There was something that didn’t feel right. And also, when I put the Driveshaft back and turned it, I could hear some slight rattle noise in the PTU, but I thought that probably it is ok, and really didn’t want to take the PTU down again.
So now, I practiced, for hours, putting back the Actuator. Finding the right angle so I can look inside it to see that it is going to the right place, and learning the feeling of it sliding into the right place. And also turning the shafts checking that there is no rattle.

That’s it, hopefully.

Thanks for posting the resolution. Would like to know your opinion about drain and fills. Is it worth doing by itself? Or is it a waste of time, and the only real way to service the PTU is take it out so you can remove the actuator and replace its motor and gasket. Replace the fluid through the actuator opening then reinstall?

 

[Gary Kline]

Thanks for posting the resolution. Would like to know your opinion about drain and fills. Is it worth doing by itself? Or is it a waste of time, and the only real way to service the PTU is take it out so you can remove the actuator and replace its motor and gasket. Replace the fluid through the actuator opening then reinstall?

Hey @Tico007 ,

Note, these are two different things...

@Assi had internal mechanical damage to his PTU (pin came out in the differential if I recall) so had to take it out and disassemble because of that.
https://www.jeepcherokeeclub.com/th...-drive-axle-driveshaft-catalytic-converter.252145/?post_id=3069652#post-3069652


This is different than just changing the fluid to do a fluid change. For that, @Flechtight did the excellent "how to" to drill a drain plug here (which if you have an AD2 PTU, is the only way to drain it with the PTU still attached to the car): https://www.jeepcherokeeclub.com/th.../threads/ptu-drain-plug-project…-completed.251893/?post_id=3066924#post-3066924

*Note, if you have an AD1, it may be possible to pump out the fluid. Not sure.

 

[Tico007]

Hey @Tico007 ,

Note, these are two different things...

@Assi had internal mechanical damage to his PTU (pin came out in the differential if I recall) so had to take it out and disassemble because of that.
https://www.jeepcherokeeclub.com/th...-drive-axle-driveshaft-catalytic-converter.252145/?post_id=3069652#post-3069652


This is different than just changing the fluid to do a fluid change. For that, @Flechtight did the excellent "how to" to drill a drain plug here (which if you have an AD2 PTU, is the only way to drain it with the PTU still attached to the car): https://www.jeepcherokeeclub.com/th.../threads/ptu-drain-plug-project…-completed.251893/?post_id=3066924#post-3066924

*Note, if you have an AD1, it may be possible to pump out the fluid. Not sure.

Hi. I guess I’ve formed an opinion that drain and fills alone don’t do much to prevent failure or a SVC 4WD light. Or even extend the life of the PTU. The only maintenance that will actually reap rewards is removal to service the actuator annd its motor at the same time. And I was just wondering what his thoughts were on that

 

[Gary Kline]

Hi. I guess I’ve formed an opinion that drain and fills alone don’t do much to prevent failure or a SVC 4WD light. Or even extend the life of the PTU. The only maintenance that will actually reap rewards is removal to service the actuator annd its motor at the same time. And I was just wondering what his thoughts were on that

Wait and see what he replies but in general, I agree with you. Unless the 4WD was used a lot/ridden hard, it doesn't get that bad in my opinion to where the oil breaks down to the point of no longer being able to provide mechanical lubrication. And the fluid really has nothing to do with what goes on inside the actuator (and definitely should never be inside the motor/circuit board part of the casing.)

 

[Assi]

Hi @Tico007, sorry for the late reply (I didn't see my messages ...).
Changing the oil is an issue that appears in this forum as a "maintenance" action. I didn't see anyone saying that it fixed "SVC 4WD" light. @Gary Kline correct me if I am wrong. Theoretically, maybe if the oil is very bad then the PTU gears won't engage? - I don't know much about it.

Regarding the "SVC 4WD" light, you can connect AlfaOBD and check further the error code of the PTU itself.
Usually when the motor is faulty you get: C14A7 “PTU Motor, Component or system operation blocked” (and correct me if I am wrong - or mixed up the code number..).
Note that if you get C1496 "PTU motor position, Performance or incorrect operation..." - in this case, it is not always a real problem, it can happen when the PTU position and the controller position has different info (this is my guess). I managed to clear it in several cases (got it several times since I played a lot with the PTU). check in here:
post#15:

https://www.jeepcherokeeclub.com/threads/ptu-code-c1496-92.248379/?post_id=3069489#post-3069489

Note - you will probably get more errors , on other modules also, that are related to the problem - like "Lost Communication" and more.

Regarding the broken pin problem I had: you can open the PTU filing plug and check the oil, this will tell you if there is grinding problem (or maybe even a broken pin like I had).
post #67:

https://www.jeepcherokeeclub.com/threads/adii-won%E2%80%99t-shift-into-4wd-low.248975/page-4?post_id=3062705#post-3062705

post#81:

https://www.jeepcherokeeclub.com/threads/adii-won%E2%80%99t-shift-into-4wd-low.248975/page-5?post_id=3063144#post-3063144

Note that that with this kind of oil sludge I still didn't have the "SCV 4WD" (others did) - but it can give you some indication.


Also removing the PTU guide - if needed:

https://www.jeepcherokeeclub.com/threads/removing-the-ptu-drive-axle-driveshaft-catalytic-converter.252145/

 

[Gary Kline]

Hi @Tico007, sorry for the late reply (I didn't see my messages ...).
Changing the oil is an issue that appears in this forum as a "maintenance" action. I didn't see anyone saying that it fixed "SVC 4WD" light. @Gary Kline correct me if I am wrong. Theoretically, maybe if the oil is very bad then the PTU gears won't engage? - I don't know much about it.

Regarding the "SVC 4WD" light, you can connect AlfaOBD and check further the error code of the PTU itself.
Usually when the motor is faulty you get: C14A7 “PTU Motor, Component or system operation blocked” (and correct me if I am wrong - or mixed up the code number..).
Note that if you get C1496 "PTU motor position, Performance or incorrect operation..." - in this case, it is not always a real problem, it can happen when the PTU position and the controller position has different info (this is my guess). I managed to clear it in several cases (got it several times since I played a lot with the PTU). check in here:
post#15:

https://www.jeepcherokeeclub.com/threads/ptu-code-c1496-92.248379/?post_id=3069489#post-3069489

Note - you will probably get more errors , on other modules also, that are related to the problem - like "Lost Communication" and more.

Regarding the broken pin problem I had: you can open the PTU filing plug and check the oil, this will tell you if there is grinding problem (or maybe even a broken pin like I had).
post #67:

https://www.jeepcherokeeclub.com/threads/adii-won%E2%80%99t-shift-into-4wd-low.248975/page-4?post_id=3062705#post-3062705

post#81:

https://www.jeepcherokeeclub.com/threads/adii-won%E2%80%99t-shift-into-4wd-low.248975/page-5?post_id=3063144#post-3063144

Note that that with this kind of oil sludge I still didn't have the "SCV 4WD" (others did) - but it can give you some indication.


Also removing the PTU guide - if needed:

https://www.jeepcherokeeclub.com/threads/removing-the-ptu-drive-axle-driveshaft-catalytic-converter.252145/

@Assi, great info and summary and yes, "cleanliness" of the oil really not a significant factor with an SCV 4WD light.