Transmission Problem

[JD0520]

Not for hire, sorry. I built a couple for friends of mine back when I had all the specialty tools, but did quite a few of my own for two of my drag cars. In ~3500lb cars, 600hp is about the limit for reliability in 60Es, a little less for heavier trucks.

The problem is when you get above the 600hp range you have a hard time keeping the aluminum input drum and steel output shafts (even 300M versions) from breaking. The only way to keep them alive is soften up the shifts, but then the 60E's relatively weak clutch packs just can't take slippage (especially the direct clutch). Just too much stress for the size of parts in this trans.

That's why as soon as anyone says they want over 600hp, especially in a truck, I immediately say convert to a 4L80E. After repeated 60E failures at 6-700hp I went to mildly built 80Es and went to 1000hp+ with ZERO problems for the last couple of years I raced.

The 60E is a hard trans to build right. It's a lot more than just parts swapping to make them live... there are a lot of "builder's secrets" when it comes to making the 60E reliable at reasonable power levels. Mostly with clearances and internal vavlebody modifications. While the guys in business won't give these out, as it is their trade they have to protect, I don't mind sharing some of what I learned.

Know of any shop in SoCal that anyone can recommend to do rebuilds or does swap 4L80E's?

 

[blueflamed03]

you da man Jay, thanks, good info indeed!!

 

[carbm]

I have a similar problem with my truck, it will drive when I put it in D but like the original post, it will only use 1,2 then if I accelerate over 30mph it will go into 4th and no OD.

It's an '01 YukonXL 4WD and it has about 180k miles on it. I'm getting ready to do a rebuild on it, unless it's not neccessary?

I was planning on using this kit:
http://www.summitracing.com/parts/TCI-378906

This sunshell:
http://www.summitracing.com/parts/TCI-373900/

and replacing any plastic parts with aluminum where available.