Intermittent Torque Converter Lock Up -1998 Jeep Cherokee XJ - AW4

[Brynjaminjones]

Okay, I've started the process of changing to a (hopefully) better ATF.

Over the last couple of months I had been draining and refilling with this Comma MVATF Plus, which is a general multi-vehicle ATF that is seemingly Dex VI compatible. I think I've done 3x drain and refills, and the fluid ended up looking much better, but still not red.

I'm now changing to this Mobil ATF 320, which seems to be a high-quality Dex IIIG. I've done 1x drain/refill so far, which changed out exactly 3 liters. I'll drive the Jeep a bit and do a couple more changes and see if there's any noticeable change.

 

[burbguy82]

I am going to get some hate for this.......but the tranny is old, and neglected. A bottle of Lucas Transmission fix would be where I would start in your situation. Maybe drop the pan, change the filter, and refill with old fluid, plus one bottle of Lucas ATF fix.

 

[Brynjaminjones]

I am going to get some hate for this.......but the tranny is old, and neglected. A bottle of Lucas Transmission fix would be where I would start in your situation. Maybe drop the pan, change the filter, and refill with old fluid, plus one bottle of Lucas ATF fix.

I have to say, I have been tempted to try that.
My wife has a 1997 Jeep ZJ Grand Cherokee with a 42RE. It has always had a problem shifting from 2nd to 3rd when cold, despite fluid changes.

I put a bottle of Lucas Transmission Fix in it, and it definitely did something because the problem immediately got much, much worse.
I ran the Lucas for a while, then dropped the pan and changed the fluid again, and now the problem is almost completely gone.

We bought her Jeep at 106k miles, and at the ~185k miles it's now on, the transmission is better than it ever was.


In my Cherokee I'm planning to keep changing the fluid with this new ATF 320, until it's finally red on the dipstick. If that doesn't help this problem, I will probably add some Lucas.
If that still doesn't help, I think I will drop the valve body and try a Sonnax "Lockup Relay Valve Sleeve Kit", here.

 

[burbguy82]

I have to say, I have been tempted to try that.
My wife has a 1997 Jeep ZJ Grand Cherokee with a 42RE. It has always had a problem shifting from 2nd to 3rd when cold, despite fluid changes.

I put a bottle of Lucas Transmission Fix in it, and it definitely did something because the problem immediately got much, much worse.
I ran the Lucas for a while, then dropped the pan and changed the fluid again, and now the problem is almost completely gone.

We bought her Jeep at 106k miles, and at the ~185k miles it's now on, the transmission is better than it ever was.


In my Cherokee I'm planning to keep changing the fluid with this new ATF 320, until it's finally red on the dipstick. If that doesn't help this problem, I will probably add some Lucas.
If that still doesn't help, I think I will drop the valve body and try a Sonnax "Lockup Relay Valve Sleeve Kit", here.

many people on here are "purists" and focus on the absolute correct, by the book thing........but, If it works, it works. I have used the product, and it has performed well for me in the past. It corrected a conditon of a delayed 1st engagement in a truck I used to have, and that truck ran for 200k.

Good luck. and for those who are formulating the attack on my post about trying Lucas, come at me bro!/bra!

 

[SwampSurvivor]

many people on here are "purists" and focus on the absolute correct, by the book thing........but, If it works, it works. I have used the product, and it has performed well for me in the past. It corrected a conditon of a delayed 1st engagement in a truck I used to have, and that truck ran for 200k.

Good luck. and for those who are formulating the attack on my post about trying Lucas, come at me bro!/bra!

I am generally a purist.

But I also know, first hand , that you can put the below in one of these transmissions without hurting it. Maybe not straight , but a mixture or concoction in an emergency.

- Random ATF
-Motor oil
-Gear oil ( pump whines)
- PS fluid
- brake fluid ( small amount)

 

[Brynjaminjones]

I am generally a purist.

But I also know, first hand , that you can put the below in one of these transmissions without hurting it. Maybe not straight , but a mixture or concoction in an emergency.

- Random ATF
-Motor oil
-Gear oil ( pump whines)
- PS fluid
- brake fluid ( small amount)

It sounds like this may be coming from experience - I'm sure there's an interesting story to back this up!


I took the Jeep for a drive today after the 3 liter change to Mobil ATF 320. I didn't reach a speed where the torque converter tried to lock up, but the transmission felt like it was shifting really nicely. I'm sure it's placebo affect, but I've convinced myself that the shifts are better than before.

I'll do another change when I get the chance, then hit the highway to see if lockup works!

 

[SwampSurvivor]

It sounds like this may be coming from experience - I'm sure there's an interesting story to back this up!


I took the Jeep for a drive today after the 3 liter change to Mobil ATF 320. I didn't reach a speed where the torque converter tried to lock up, but the transmission felt like it was shifting really nicely. I'm sure it's placebo affect, but I've convinced myself that the shifts are better than before.

I'll do another change when I get the chance, then hit the highway to see if lockup works!

There was a time when you could pick up a beater Cherokee here for $500. So we had one as an offroad club loaner. I was borrowing it on a mud run and beating the snot out of the thing. Foot to the floor jamming drive and reverse without letting up. The transmission cooler line ripped off and in the middle of one of the hard runs it pumped itself dry and stopped working. So I fixed the line, filled it up with ATF and kept going ... then it happened again.

It kept happening and we just kept trying whatever fluids were on hand to keep it going. The transmission was run dry probably 10 times that day.

A year or two later the jeep spent a few weeks submerged. The transmission stopped working. So we pulled the pan, threw another used filter on it and scraped out the sludge in the bottom of the pan and it kept going.

The jeep itself got too wrecked to use. Then the front differential locked up and it got crushed.


We did some snow rides this winter with LOTS of snow. The only way through that was wheel speed and never stop moving. So it'd be rev limiter in 1st gear forward until momentum stopped, then instantly reverse and rev limiter in reverse. Lots of rocking.

For an otherwise low quality vehicle, these transmissions are probably the most reliable part of it.

 

[burbguy82]

I am generally a purist.

But I also know, first hand , that you can put the below in one of these transmissions without hurting it. Maybe not straight , but a mixture or concoction in an emergency.

- Random ATF
-Motor oil
-Gear oil ( pump whines)
- PS fluid
- brake fluid ( small amount)

i would not advise putting any motor oil or gear oil in at all.

i once pur dex3 on accident and it shifted funny, did a couple drain and fills with atf4 and was good ......99xj

 

[Brynjaminjones]

There was a time when you could pick up a beater Cherokee here for $500. So we had one as an offroad club loaner. I was borrowing it on a mud run and beating the snot out of the thing. Foot to the floor jamming drive and reverse without letting up. The transmission cooler line ripped off and in the middle of one of the hard runs it pumped itself dry and stopped working. So I fixed the line, filled it up with ATF and kept going ... then it happened again.

It kept happening and we just kept trying whatever fluids were on hand to keep it going. The transmission was run dry probably 10 times that day.

A year or two later the jeep spent a few weeks submerged. The transmission stopped working. So we pulled the pan, threw another used filter on it and scraped out the sludge in the bottom of the pan and it kept going.

The jeep itself got too wrecked to use. Then the front differential locked up and it got crushed.


We did some snow rides this winter with LOTS of snow. The only way through that was wheel speed and never stop moving. So it'd be rev limiter in 1st gear forward until momentum stopped, then instantly reverse and rev limiter in reverse. Lots of rocking.

For an otherwise low quality vehicle, these transmissions are probably the most reliable part of it.

Haha, that's an awesome story, thanks for sharing!

I do really like this AW4 transmission, although it has given me more problems than the old 4.0 ever has. Rust aside, these vehicles can really hold up well in my experience.


I've done another drain and refill today - got another 3 liters out. The fluid is starting to look something like it should, so I'll keep going!

 

[D60]

I too am not opposed to a miracle in a bottle as I've had good experiences with Seafoam TransTune in Fords (6R140 and 4R70). It seems -- in cave man terms -- the Lucas may make the fluid more thickerer while Seafoam might make it more thinnerer. I'm willing to believe the latter can aid sticky solenoids.

This is all my cave man brain can handle ‐‐ "MAKE FIRE, KILL SOMETHING!!"

 

[JHZR2]

I don’t know about the AW4 transmission, but how does the computer get a TPS signal?

If have intermittent lockup issues on my 47RE in my 96 Dodge, but it wasn’t always, wasnt consistent.

I know you said before that you identified that it isn’t electrical, but have you actually tried a different TPS to ensure that the right signal is truly continuous?

Very short dropouts may be hard to see in some cases.

 

[Brynjaminjones]

I don’t know about the AW4 transmission, but how does the computer get a TPS signal?

If have intermittent lockup issues on my 47RE in my 96 Dodge, but it wasn’t always, wasnt consistent.

I know you said before that you identified that it isn’t electrical, but have you actually tried a different TPS to ensure that the right signal is truly continuous?

Very short dropouts may be hard to see in some cases.

Yeah, I'm on my 3rd TPS now since I started chasing this problem.

I've also got an incandescent bulb wired up to show me when 12V is being sent to the solenoid.

Once it locks up, it never unlocks when it shouldn't - the problem is that it often fails to lock in the first place.

I'm still open to it being an electrical issue, but all signs so far are pointing to something else.

 

[JHZR2]

Yeah, I'm on my 3rd TPS now since I started chasing this problem.

I've also got an incandescent bulb wired up to show me when 12V is being sent to the solenoid.

Once it locks up, it never unlocks when it shouldn't - the problem is that it often fails to lock in the first place.

I'm still open to it being an electrical issue, but all signs so far are pointing to something else.

And you verified the voltage and voltage offset?

As I recall on the old Dodge trucks, that can be a thing too…

Then you’d get the 12v but you would not get it at the right time if the signal voltage wasn’t correct.

 

[Brynjaminjones]

And you verified the voltage and voltage offset?

As I recall on the old Dodge trucks, that can be a thing too…

Then you’d get the 12v but you would not get it at the right time if the signal voltage wasn’t correct.

I've not verified the voltage, but the incandescent bulb I'm using lights up with the exact same brightness every time - it never dims or flickers once it's lit.

As for voltage offset - I may be misunderstanding, but I feel like that may not apply here. The voltage I'm testing is not sensor voltage, it's the voltage (12v) direct to the solenoid itself. According to the bulb, this voltage is being applied exactly when it's supposed to.

I completed my final fluid change last night, and for the first time in the 13 years I've owned this Jeep, the fluid is nice and red on the dipstick.
I've just been for my first highway drive after swapping out the fluid.

I first got on the highway about 5 minutes after cold-start, and although it locked up great, the lockup didn't engage until about 5 seconds after the light came on to let me know that 12v was being applied.
After this, it worked well. It would disengage when I applied enough throttle to kick down, coasted or braked, and it reengaged within about a second of the light coming back on.

I then drove around town running some errands, where the Jeep got a little hot in traffic. After this I got back on the highway to head home, and the lock up wouldn't work at all. The light came on, but nothing happened.

I'm glad I've now got good, clean fluid, but it doesn't seem to have improved the issue at all.

 

[JHZR2]

I've not verified the voltage, but the incandescent bulb I'm using lights up with the exact same brightness every time - it never dims or flickers once it's lit.

As for voltage offset - I may be misunderstanding, but I feel like that may not apply here. The voltage I'm testing is not sensor voltage, it's the voltage (12v) direct to the solenoid itself. According to the bulb, this voltage is being applied exactly when it's supposed to.

I completed my final fluid change last night, and for the first time in the 13 years I've owned this Jeep, the fluid is nice and red on the dipstick.
I've just been for my first highway drive after swapping out the fluid.

I first got on the highway about 5 minutes after cold-start, and although it locked up great, the lockup didn't engage until about 5 seconds after the light came on to let me know that 12v was being applied.
After this, it worked well. It would disengage when I applied enough throttle to kick down, coasted or braked, and it reengaged within about a second of the light coming back on.

I then drove around town running some errands, where the Jeep got a little hot in traffic. After this I got back on the highway to head home, and the lock up wouldn't work at all. The light came on, but nothing happened.

I'm glad I've now got good, clean fluid, but it doesn't seem to have improved the issue at all.

At least on my Dodge, the TPS is a 1-5V signal, as I recall. It is fed 5V from the computer, and returns a 0-5V signal.

Here was my situation, with a 440k mile Dodge:

https://www.cumminsforum.com/threads/tps-more-or-less-checks-out-now-what.2536122/

And,

Thread 'P0123 TPS High & C0322 - will not clear - 1996 Ram CTD 47RE'

Nov 30, 2020

I’m creating a new thread because this is more related to OBD. I had asked before about my 47RE searching under light throttle, 45-60 MPH. It’s very random. I can be driving long distances at these speeds and encounter no TC lock/unlock, or I can have it happen continuously, even if I force the transmission to turn OD off.

https://bobistheoilguy.com/forums/threads/ram-47re-tc-searching.333730/

So I got my hands on a scan tool, wanting to take a look at live data... The truck does not have any CELs, and shifts very well, except when it’s doing this funny business. AC ripple and/or...

• JHZR2
• Replies: 10
• Forum: Mechanical/Maintenance Forum

• 

My point was that sometimes an instantaneous glitch is all it takes. Your 12v to the solenoid isn’t the same data the computer is getting from the tps. Choppy tps voltage can be a cause.

 

[Brynjaminjones]

Understood, thank you.

Just to clarify though, the 12v being sent to the solenoid is the actual command for the solenoid to lock up from the TCM - it's only present when the solenoid should activate.
The fact that the 12v is present means that all of the electrical control systems are working properly, including the TPS.

 

[Rob_Roy]

Thank you all. I need to do more changes anyway to continue to clean up the fluid, so I'll find some genuine Dex III with a higher viscosity rating and see how I get on.

I still don't feel like this problem should be happening though - surely it shouldn't be this sensitive to viscosity. I'll be happy if I can minimise the issue with the fluid, but ideally I'd find a 100% fix.

Does anybody have any thoughts on the Sonnax lockup relay valve shared in the OP?

I would install the Sonnax kit. TransGO also makes a kit for this transmission and lists TCC issues as one of the intended corrections.

Last summer I dropped the valve body in my Suburban and installed a “shift correction kit”. With 190k miles it now shifts better than it did when it was new.

 

[Brynjaminjones]

I would install the Sonnax kit. TransGO also makes a kit for this transmission and lists TCC issues as one of the intended corrections.

Last summer I dropped the valve body in my Suburban and installed a “shift correction kit”. With 190k miles it now shifts better than it did when it was new.

I'm considering that. The lockup solenoid is about 10 months old, but I'm considering replacing it again and installing the Sonnax kit at the same time.

The Sonnax kit looks to be the right one - it is the only one that includes the "Lockup Relay Valve Sleeve", which is apparently the main part that causes this concern in this version of this transmission.

The good news is that it can be installed without reaming, so I'd just need to pop the valve body off.

 

[Brynjaminjones]

Okay, I've pulled the trigger.

I found a local (UK) supplier who can get the lockup relay valve sleeve kit from Sonnax for me. It will take about a month, but I'm fortunate enough to have another vehicle I can for highway trips in that time. I'll just use my Cherokee for town driving for a while!

They also had the lockup solenoid in stock for a great price, so I might as well try replacing that again while I'm in there.

I really hope this fixes it - we have plans booked to take this Jeep on a road trip in France in a couple of months!