3-4 gone again am i missing something?

[fullforce]

So my 3rd and 4th gear went out a year ago at 99,000 miles I completely rebuilt the trans (my first automatic) and it has shifted FLAWLESS all year and Ive put about 6,000 HARD miles on it since then.
Then today I left work at light throttle and 2nd was fine, 3rd was fine, then 4th was ok untill the converter locked then it went to NOTHING... had to go back down to 2nd and limp it home.

Is there anything that is a common problem to continue causing the 3-4 piston to blow? I know its a issue with these 4l60's but I thought id atleast geat 50k miles out of it.
Any advice for when I tear it back apart would be appreciated.

[SSlowBoat]

So my 3rd and 4th gear went out a year ago at 99,000 miles I completely rebuilt the trans (my first automatic) and it has shifted FLAWLESS all year and Ive put about 6,000 HARD miles on it since then.
Then today I left work at light throttle and 2nd was fine, 3rd was fine, then 4th was ok untill the converter locked then it went to NOTHING... had to go back down to 2nd and limp it home.

Is there anything that is a common problem to continue causing the 3-4 piston to blow? I know its a issue with these 4l60's but I thought id atleast geat 50k miles out of it.
Any advice for when I tear it back apart would be appreciated.ask Cahall

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[CPT]

There are atleast 6 different design flaws in the 4L60E that directly feed into repeated 3-4 clutch failure. They have to do with timing, pressure, clamping force, and clutch/steel type and material. The largest percentage of other "professional builders" still have a hard time getting the 3-4's to hold up. It's taken me many years, a lot of research, trial and error, and a very specific understanding of the 4L60E to be able to get the 3-4 clutch life that I have.

[fullforce]

Guess ill pull it back down and try again! lol

[popo8]

Why not ship it out to frank and have it reliable.

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[fullforce]

I would LOVE TO!!!
but..... Ive got project 72 trans am that is getting the attention right now and a spare vehicle so I cant really justify it with the wife ....

It just seemed weird how it suddenly lost all holding power in 3rd ad 4th, not even a slip just NOTHING in a split second

[fullforce]

38104

[superspirit]

Time for a beast shell!

[CPT]

Time for a beast shell!

What does the sun shell have to do with this failure?

Frank

[CPT]

38104

3-4's burnt up and gained a bunch of clearance. Once that happens, you get a "slide hammer" effect on the clutch pack that will blow the lugs out of the drum.

Frank

[fullforce]

It never once slipped 3rd, I probably had too much clearance to begin with since I failed to check it....

[fullforce]

Also I belive it happened after a wot 1st and 2nd pull then I let off the throttle at the top of 2nd and let it shift into 3rd with no load witch may have cause it to slam 3rd hard.