32RH Help

[Stoshzack]

Hi All -

Any experts out there on the 32RH automatic transmission? I recently rebuilt mine for my 1998 TJ and just re-installed it.

I can start it in park and neutral only, so I think the shift linkage is adjusted correctly. I can also roll it backwards in neutral with the engine off.

However, it moves forward in neutral with the engine on. Also, when I shift into reverse, it shifts into reverse and starts to move, but then stops; almost like it is binding. I am thinking the reverse band is fighting against a stuck forward clutch staying engaged.

Any thoughts? Maybe a stuck forward clutch piston?

 

[lBasket]

If only there was a 32rh expert to hear your issues

 

[Stoshzack]

So, I think I figure this out.

The rebuild kit I got from Oregon Transmission came with only one thickness friction plates: 0.060”. This is the correct thickness for the rear clutch. However, the front takes 0.086 when using four steelies. I noticed the difference in thickness on install, but did not account for it. None of the videos I watched talked about it. With that said, the 0.060” friction plates allow the builder to add an extra steelie and clutch plate to the front drum (i.e five steelies instead of FSM four). This lack of thickness created a larger clearance on the front drum, which I did not measure to confirm.The larger clearance allows the front drum to engage in neutral when it should not., The front drum rotating combined with the rear drum rotating on reverse causes it to bind. Also, the front drum rotating caused the Jeep to move forward when in neutral.

 

[hear]

Did you check your clearances on both drums after you replaced the clutches & steels? But I'm not sure I buy your explanation. Too much clearance would mean that potentially even under pressure the clutches wouldn't grab. Too little clearance and the clutches would drag at all times, and could make you move in neutral. I'll just add that even with the proper clearance, fluid coupling alone is enough to make the output shaft spin vigorously if there is no load on the output (i.e. driveshaft disconnected). If you're creeping in neutral you have clutch drag (but why?), not excessive clearance.


Also thickness of the clutches isn't really a spec, at least as far as I've ever seen (or remember seeing, anyway). They are what they are and you use a selective snap ring to set the clearance properly. But you are correct in that the front and rear are slightly different in the banner kit, and one way will allow for one of the clearances to be in spec but the other won't. You possibly watched my videos, and I definitely didn't know this when I did those, I just happened to guess correctly on which clutches went in which drum. 50/50 chance, right!?

 

[Stoshzack]

Hi @hear

Thanks for your reply. I watched your videos, so thanks for that.

I made the mistake of not checking clearances or doing an air test as I should have. The rebuild kit I got from Oregon Transmission did not have different thickness friction plates. That confused me on re-assembly. A member on a Mopar forum suggested I check clearance on the front clutch pack. He stated that wrong clearance can cause the ‘piston to "overtravel" and engage the transmission without pressure’. That reminded me that the friction disks had a smaller thickness than what came out. I just assumed that was the problem.

If you have any ideas, I am all ears!

 

[hear]

With all due respect to a person I've never met, she doesn't know what the f she's talking about. If the clearance is too large, it will require the piston to travel further to make the frictions grab. It might mean that it can't travel enough to actually grab, and you'll get slipping or zero engagement. If the clearance is too small you'll have the frictions engaged w/o pressure being applied, which would give you all sorts of weird stuff, including neutral creep.

Creep is a result of too much clutch drag, which is either insufficient clearance or inadvertent pressure (either applied or an inability to un-apply). A pressure test as detailed in the FSM would probably tell you a lot.

Did you replace the skirt seals on the drum pistons? It's possible you put them in backwards or folded them, so they're holding pressure. An air test only requires removing the valve body, and you can hear if the clutches apply & release. It could also be a sealing ring problem on the input shaft, or some sort of bleedover problem in the valve body. Did you overhaul the VB too?

The question I should've asked out of the gate is what caused you to need to rebuild it in the first place?

 

[Stoshzack]

Bought refurbished valve body from Central Valve Bodies and sent my core in.

I did install new skirt seals. Orientation was correct, but I guess they could have folded. Rotated piston on install to try to avoid this.

I rebuilt Tran because I was having a flare occur between 1st and 2nd gear. When I pulled it apart, it looked pretty good inside. Jeep is new to me.

 

[hear]

I see you like to live dangerously.

Did you do the sealing rings? Those are the biggest mystery of them all. I've read horror stories of guys doing everything only to discover that the ring seat was too wide by a couple thou and nothing would work right. I'm not saying that's what it is, but it also easy to kinda bone that step. What about the drum bushings? I don't think I have any video of that step, but only once have I had a bushing that was clearly shot. Assuming you're not under spec on clearance, something is supplying or holding pressure on the clutches.

Other ideas:
* manual valve isn't landing just right, so it's allowing some fluid to move in the drive fluid path
* weak piston spring not forcing the piston to return after it's applied - If you let the jeep sit OFF for a while, then put it into N and then start it, does it still creep?
* input shaft endplay clearance issue? I have too much going on at work to fully process what this might look like...
* i read something that said an overtight kickdown band might cause this (though I'm not sure how just yet) - loosen the kickdown band adjust and see if it still creeps
* any number of valve body problems

 

[Stoshzack]

Thanks for all the ideas. At this point, I think I need to pull it and check clearances. Ugh. I’ll check piston seals too.

Changed some of the rings, but not the bushings.

 

[hear]

before you drop it, back the kickdown adjuster way off and see if you creep. Then turn it off, let it sit, and start it in neutral and see if you still creep. Then drop the VB and air check it.

Don't drop the transmission before you do those tests.

 

[lBasket]

I see you like to live dangerously.

Did you do the sealing rings? Those are the biggest mystery of them all. I've read horror stories of guys doing everything only to discover that the ring seat was too wide by a couple thou and nothing would work right. I'm not saying that's what it is, but it also easy to kinda bone that step. What about the drum bushings? I don't think I have any video of that step, but only once have I had a bushing that was clearly shot. Assuming you're not under spec on clearance, something is supplying or holding pressure on the clutches.

Other ideas:
* manual valve isn't landing just right, so it's allowing some fluid to move in the drive fluid path
* weak piston spring not forcing the piston to return after it's applied - If you let the jeep sit OFF for a while, then put it into N and then start it, does it still creep?
* input shaft endplay clearance issue? I have too much going on at work to fully process what this might look like...
* i read something that said an overtight kickdown band might cause this (though I'm not sure how just yet) - loosen the kickdown band adjust and see if it still creeps
* any number of valve body problems

Me, wondering if this is actually worse than pulling an entire motor just to push flywheel dowel pins in 1mm

 

[hear]

Me, wondering if this is actually worse than pulling an entire motor just to push flywheel dowel pins in 1mm

IDK, I've never had to do that. But I hate pulling a transmission.

 

[Stoshzack]

before you drop it, back the kickdown adjuster way off and see if you creep. Then turn it off, let it sit, and start it in neutral and see if you still creep. Then drop the VB and air check it.

Don't drop the transmission before you do those tests.

Will do. Thanks