OD Slipping

[excrider121]

98 T/A 5.7


The transmission was 'slipping' out of OD after about 20 minutes in OD 1 year ago. You could get it to go back into OD by manually putting it in 3rd, then back in Drive and it would work for another 10-15

I rebuilt it. It fixed the problem for about 2 months and then it came back.


3 days ago, I completely lost OD and 3rd gear, so I did some research and found that the four seals on the input shaft were probably chewed up and that I'd need to replace them as well as rebuilt the 3-4 clutch pack. So I bought the seals, and the clutch pack, along with the EPC. I also changed the filter and fluid.

I put the transmission back together and it STILL slips out of OD after about 25-30 miles. Only this time, when it slips out of OD, you can just let off the gas for the count of 3 and when you try to accelerate again it is back in gear all by itself.


I'm feeling defeated and don't have a clue what else to check.



Any one have any ideas?

[Rock-On]

Not enough info ...have you changed your stator bushings?? how did you install your rings,on your input shaft? The 3-4 clutch system has many hydro leaks and will leak off after this unit reaches operateing temp.

[excrider121]

Stator bushing was not replaced and looks to be in good condition. No scoring and the vaynes were immaculate.

The rings on the input shaft soaked in transmission fluid for 20ish minutes and were installed using a pick to minimize stretching. Once the rings were in place, they were wrapped in a square piece of rubber cut out of a rubbermaid container and hose-clamped together. After 4 hours, the clamps were removed. When I put the pump on the shaft, it slid down so easily with no resistance at all.


What hydraulic leaks do you know of? The more info the better, I'd rather check too many things, than not enough.

[Rock-On]

Hey Listen up, When you say the teflon seals ,went on with no resistance at all thats more than likely your problem, next time you do the input shaft teflons...... instead of useing rubber maid and hose clamps use your stator shaft to resize your rings and you wanna feel a slight resistance, when installing the pump on you input shaft.

Next, you wanna go to your nearest transmission supply house get a transgo HD 3-4 return springs, fallow directions, make sure you replace the capsual in the input drum this is a major source of leaks in the drum. While this unit is apart, go into the pump, again go to the tranny house and get a transgo hi-rev no YO_YO,hardened ring kit fallow directions, you need to increase pump slide resistance, thus inproving fliud flow and pressure.

While your in the drum remove the 3rd clutch piston, if its the molded steel -rubber,piston,THIS PISTON IS A MAJOR LEAK WILL AIR TEST FINE WHEN IT WARMS UP IT LEAKS LIKE A SIVE.Replace it with an early style piston and rubbers ,don't worry its a direct fit.

While your setting up the 3rd clutch, remove the #7 fingers,replace with the #4 or no number fingers these are longer & will support the 3rd clutch apply plate better. This will speed up the 3rd apply.

make a note anytime you replace the input shaft seals you must replace the stator shaft, bushings. This input drum weighs in at 19 lbs, the only support is theses bushings, and rotates at engine speed. 2.00 is pretty cheap insurance, why risk it?

I hope this helps you out this is a good start, there are other leaks that need to be addressed these are your major leaks, and the others MOD's require drilling, tapping, grinding and valve body mods. Good Day Dave (simpsons came on gotta go)

[Rock-On]

I forgot, when you have your pump out, look into your stator, there should be a mirrow finish, where these teflon rings ride, you'll see four holes that are sppose to be there, make sure the input shaft hasn't gotten into the sleeve. NotE: if you get a used stator laying around from the t/c side drive the sleeve otta the stator shaft and use it for a ring sizer,,Thats what I use,sizes the rings perfectly. Hope this helps Dave sorry so long of a post...

[Cutlass]

Hey Listen up, When you say the teflon seals ,went on with no resistance at all thats more than likely your problem, next time you do the input shaft teflons...... instead of useing rubber maid and hose clamps use your stator shaft to resize your rings and you wanna feel a slight resistance, when installing the pump on you input shaft.

Next, you wanna go to your nearest transmission supply house get a transgo HD 3-4 return springs, fallow directions, make sure you replace the capsual in the input drum this is a major source of leaks in the drum. While this unit is apart, go into the pump, again go to the tranny house and get a transgo hi-rev no YO_YO,hardened ring kit fallow directions, you need to increase pump slide resistance, thus inproving fliud flow and pressure.

While your in the drum remove the 3rd clutch piston, if its the molded steel -rubber,piston,THIS PISTON IS A MAJOR LEAK WILL AIR TEST FINE WHEN IT WARMS UP IT LEAKS LIKE A SIVE.Replace it with an early style piston and rubbers ,don't worry its a direct fit.

While your setting up the 3rd clutch, remove the #7 fingers,replace with the #4 or no number fingers these are longer & will support the 3rd clutch apply plate better. This will speed up the 3rd apply.

make a note anytime you replace the input shaft seals you must replace the stator shaft, bushings. This input drum weighs in at 19 lbs, the only support is theses bushings, and rotates at engine speed. 2.00 is pretty cheap insurance, why risk it?

I hope this helps you out this is a good start, there are other leaks that need to be addressed these are your major leaks, and the others MOD's require drilling, tapping, grinding and valve body mods. Good Day Dave (simpsons came on gotta go)

Nice tech info there!!!

[excrider121]

Thanks Rock. The next time I can get a free weekend, the Tranny will come out and I'll replace those parts. I'll let you know if I'm having any other issues.