I ran into a problem with my T56, so I thought I'd post and let people know.

When I rebuilt my trans I found that one of the bolts in the shift plate (the one inside the trans) was stripped. It was the one closest to the tailshaft housing. I bought a Helicoil kit and redid both the bolt holes just to be safe. The boss for the front bolt is very thin, and there wasn't much left after the drill and tap process, but I figured it would be fine, because I've never had a Helicoil fail.

A while later, and many hard shifts too I might add, I couldn't seem to get the trans into reverse. I noticed that the other shifts were rougher than normal too. I knew something was wrong so I pulled thew trans and tore it down.

The front boss had fractured and allowed the shift plate to walk around, causing all of my problems. I took the case to my machine shop and had them heli-arc new metal into the boss, spot face it, and drill and tap it.

I learned my lesson, but it cost me $150. That's not even so bad, the real pain is that I had to pull the trans, tear it down, and reassemble it. If you ever find the same problem, just get it welded up front. It'll save you a big PITA!

 

thanks for the heads up

 

ditto

 

did you use a solid insert, or a coiled-up heli-coil type? I'd risk the solid insert myself.

 

I used the coiled type of insert. Looking at how thin the remaining boss was after drilling and taping I wouldn't risk anything but welding in the future. There was only maybe 1/8 of an inch of material remaining, and that had threads cut into it internally. The problem wasn't the insert, rather that the remaining boss was too thin. The insert was still intact and wrapped around the bolt. The front part of the boss was in several pieces inside the trans. Thankfully none of the bits got lodged in anything important.