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elwrencho 10-26-2009 05:27 PM

4L60e slipping in 2-4

Rebuilt trans ,kit with steels ,new converter, new band and filter.
I test drove vehicle everything fine, customers drives feels a slip going to 2nd gear. I retest drive vehicle to conform, yes it slips going to 2nd and 4th "customer drove car harder than i ever have or would" .

So i pull trans back out find no problem with servo seals or pin binding in case, rolled case over poured fluid in worm track right above check ball capsule "3rd accumulator" no fluid leaking into case "good right" ? i have never had to replace one, but i have heard of others replacing them.

When trans is cold and band was fresh you could have not asked for a firmer 1-2 shift 2-3 not as firm but typical, 3-4 same.

one thing does come to mind tho, i had to replace reverse input drum, this trans had been apart for some time and this part was left in"weather" to rust, so a friend who rebuilds transmissions too gave me a drum that had been sanded with a DA sander guess 220 grit"he said it would help seat band?? i think drum needs to be smooth as glass not rough feeling like this one was. Anyways 2 bands "and 2 R&R's" later it still slips going to second and fourth,Im at wits end on this one "having the flu isn't helping" :(

All accumulator pistons and seals are fine ,no valves in vb are stuck, pressures seem to be fine, according to my scanner trans fluid was up to 240 but i think that was due to slipping ,not causing the slip "it worked great cold'

Any pointers as where to look for problems??

Crosley 10-26-2009 06:40 PM

the sanded drum has nothing to do with your problems.

What is the main line pressure doing during operation? In each gear as the vehicle is driven?

Your comment: "pressures seem to be fine" ,,, what does that mean? What are the pressure readings?

elwrencho 10-26-2009 07:48 PM

Sorry for the pause in between post, i still have flu and even typing is strenuous.

I could only check pressure in P R N @ "the tap is above shifter and it won't let it past @" i didn't road test it thinking i might try to shift to 3rd and break fitting off in case.I'm getting a 90 elbow fitting soon as I feel good enough.....
P110 min 190 max R 130 min 200 max N 110 min 180-190 max @110 min 200 max
When checking pressures on road test can i leave it in @, or will i need to do each manually? I loaned my ATSG book out so i no longer have a reference for pressures.Any and all help is appreciated, thanks for your time..

elwrencho 10-28-2009 09:31 PM

I thinking I'll be pulling this unit back out this weekend "pretty sure band is toasted ,again". I have a rebuilt pump and a new manifold pressure switch,Also will be replacing capsule check ball in servo bore "3rd accumulator", any other suggestions while I'm in there ?? Again thanks in advance. The EPC in it now was out of a working unit I saved,is it possible both are bad, doing same exact thing?

btw, the customer is my nephew, Transmissions aren't my specialty just trying to help out family when I can.

MAYNARDTRUCKIN 10-28-2009 10:44 PM

this might help
Did you rtv the pan to the case? if so check if the 2,4 servo vent hole is clear also double check the seals on the servo. might just save u from pulling the trans again.

elwrencho 10-29-2009 12:11 PM

No, I never use rtv on transmissions.Servo vent hole is clear,gasket has cut out for it.I have checked servo twice, I air tested servos through both feed holes "2nd-4th", band applied seem to be no problems. I was hoping to find a bad seal, of course with my luck I wasn't surprised, it's never something simple for me.
I do appreciate you taking the time and effort on this, don't give up :)

elwrencho 11-30-2009 09:32 PM


I have put this on the back burner until now, I have fittings to test pressure in all gears, if i report back with pressures can you find the time to help me out ?

MAYNARDTRUCKIN 12-01-2009 07:09 PM

I dont have the pressur spects for the trans but the only thing that i can think of is a check ball or a seal that has a small bad spot only affected buy the higher pressurs of the trans. also the drum that the seal rides in could be flawed all it takes is something small and hard to find .

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