Tranny rebuilt 4l60e 1995 still with harsh 1-2 shift, help with springs?

95Noobie said:

Thanks Vic!
Yes, Nick has been helpful and clearly understands these things down to the finest detail. He shared a picture but I can't still get one detail straight. Maybe you can help? When I go back in to put the piston upside down and legs up like in his picture, I get it that the spring then goes on top of the piston against the plate. But does a spring go UNDER the piston too? I can't see that in his picture. It would seem like there would have to be something under the piston to help move it up if it wants to go all the way down as I'm not aware of any fluid pressure that would exert UNDER the piston to push it back up. Once I can understand that I can drop the pan and flip the piston.

As to having a shift kit in the valve body, I can ask my last tranny builder.. I would say no, I would think he would have seen that when going through it all, but I can check.

I'm pretty confident the 3-4 accumulator is untouched. The only change was to take the 1-2 accumulator which came to me with 3 springs inside and the piston setup that the later model trucks use and I switched it to a sonnax pistonless thinking the hard shift was due to wear around the pin. When I took the original 1-2 accumulator out there didn't seem to be any wear or slop around the piston in its housing or in the piston hole so i wasn't sure it would fix anything to make it pistonless and sure enough it didn't.

That means that if it was designed to have the piston upside down with single spring on top i should at least try that. But as Nick said, several other things in the valve body could be wrong and the servo clearance needs to be checked as well.

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NickTransmissions said:

You're way overthinking this....Put the spring in the housing just like you see it in that picture then bolt the housing onto the case over the plate - torque the three 10mm bolts to 104 inch lbs - DONE!

Once you have done this, put the filter, pan back on (98 inch lbs on the 16 pan bolts), refill with fluid and take it for a test drive. If you still have harsh 1-2 shifting, simply take the transmission or entire vehicle back to the transmission builder (or another, more knowledgable builder) and have them deal with it.

So unless you are willing to:

1. drop the valve body
2 disassemble the valve body
3. vacuum test the valve body
4. install corrective valves in the TCC regulator/isolator valve, AFL and/or eleswhere as needed
5 measure your servo travel and adjust band clearance
6. test your EPC

I would not bother with it beyond replacing the 1-2 acc housing/piston/spring.

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95Noobie said:

Thanks for the instructions. I changed piston to upside down configuration with no spring under it so it bottoms out on its own, legs point up, single spring above. Put it all back together, refilled fluid, test drive, no change. Perhaps even a bit harsher than when there were two springs between the bottom of the accumulator and the piston and piston legs pointed towards the ground. If I let off the throttle right when anticipating the shift it goes pretty well, any steady throttle or accelerating throttle it will hang and hang and then jerk abruptly.

I'm going to assemble the remaining steps and tests to do into a helpful document and present it to a transmission shop. I'm asking around to see who would still have experience working with 30 year old transmissions.

I love how the other gears shift, very quick and rapid, quite precise shifts both upshift and downshifts.

Prior to creating this post on the tip of another user I swapped the engine computer and PROM to rule out excessive line pressure and that was not the issue either.

I'm not sure how they access or read any transmission electronic codes since that cannot be done through the obd1/ALDL port.

Will report back if we find anything out.

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