I did a recent rebuild on my 1992 tranny this spring with all new clutches and steels. I also installed it with a Transgo kit and the "3-4 high rev spring kit".

It was working good until I took it to the strip and did about 5 full bore passes in overdrive. At the end of the strip in top 3rd gear I heard the trans let go all of the sudden. The rpms flashed from about 5700 up to 7000 and I immediately let off the gas. I also floored it again on the way home and managed to get it to let go again in top 3rd (about 5800 rpms)

There was a strong smell of burnt clutches and the fluid looked darker than normal so I took it apart right away to rebuild thinking that the 3-4 clutch pack was toast.

As it turns out the 3-4 clutches and steels are ok (within spec) but the 2 overrun clutches are totally wiped and the steels are burned badly. All other clutch packs were still in great shape.

I did notice that the TCC was coming on just before the trans let go because the temp switch was engaging it. I suppose this meant that it was actually in 4th when it slipped. (So maybe it was really slipping while shifting into 4th)

In anycase, does anyone know what happened here? How could I fry the overrun clutches and not the 3-4 clutches? I thought the overrun clutches are never applied in OD, especially at WOT???

 

I noticed that the forward clutch pack is way under what is supposed to be... about 0.020 if even that. That is measuring between the top clutch and the pressure plate. Could this be applying the overrun plates when they are not supposed to be?