i had a rebuild done on the 4l80e transmission that is in the 1994 chevy suburban k2500 w/ 6.5 turbo- i purchased a few months ago - i drove it for about 3 weeks around town- as soon as i take it on a roadtrip- the tranny burns up on the highway doing about 75mph- it has a 3 year warranty so the transmission center is doing another rebuild- the tech told me that: (1.)- the converter clutch is not applying and (2.)- the brake switch is in conflict with the cruise dump switch- they are both supposed to work in tandem (on/on , off/off) but are showing opposites in the diagnostics. i was told that this might cause the tranny to fail again- so they are working on the issue and i am doing my own research- can someone please tell me if this has been heard of before and what a fix might be?

the engine had been replaced in this vehicle due to cracked heads, injection pump was replaced- vehicle was driving well at first until i noticed a shifting problem and then the pump seal blew- that is why i had the first rebuild done...... just trying to make sure i don't burn up the next rebuild..... also i am adding an auxilary tranny cooler to try and keep it as cool as possible.

thanks for any info

regards
brian

Take it to GM & pay for a diagnosis when you get back from the wannabe Jackleg tech. Things are only hard when there is a lack of knowledge.

I would tend to agree that your shop may not know these very well. I know my 95 brake/TCC switch works the way yours does (brake applied= 1 ON, 1 OFF, and vice versa).

Have them show you the diagnostics they're using.

If the warranty is honored anywhere else, call the warranty company, explain your concerns, and see if they will take it to a different shop (a dealer that does a lot would be ideal, they'll have all the special tools needed to actually do the measurements required, as opposed to just stuffing new clutches in there and shipping it out).