So, I had an LT1 T56 bolted up to my 305 before I went LSx. The t56 had less than 5k on the rebuild that I had done so I figured I could just swap front plates/etc and be good to go. Well I have a problem now. After letting the new motor idle for awhile and burp the cooling system I had to bleed the brakes before I went on my initial voyage the next day. I shifted through all the gears with it off, started the car up (I had the car in neutral/clutch not pressed up to this point). Pushed the clutch in and repeated the shifting through the gears and now it's stuck in reverse. Not the shifter, the trans itself. If I start the car it will just back up. I can hold the clutch and brake and it will sit still but want to reverse. As soon as I let the brake go the car backs up. No matter what gear I place the shifter in, even in neutral.

Suggestions? I'm going out to the garage right now because I'm sure I'm going to have to pull the trans... What should I look for internally?

 

Can you pull the shifter and verify that the shifter cup is still there and you can shift the trans into various gears without the shifter? Could you have just missed the shifter cup with the shifter when reinstalling it? (easy enough to check)

Who swapped the mid-plate on the trans for you? Sounds like the 5/6/R shift rail may have jumped off the guide pin during the swap? It's tough to do, but it can happen if the trans is not handled gingerly during the R&R of the mid-plate when there's no support for the front of the rails.

 

Hey thanks for the suggestions. The shifter/cup was good and solid. I have a pro5.0 stabbed in there now. I did the original rebuild as well as the newest front plate/input shaft swap. When I finally got a chance to pull the trans and take a look I found the snap ring that holds the reverse synchro in place popped out of it's channel on the shiftail. Made sure it fit tight in place and slapped the tailshaft housing back on. Should get some time to put the trans back in the car this weekend sometime.

 

I’m having the same problem and going to pull the transmission in the morning, could you tell me if that was the problem? I was going down the road when it locked in place but it’s doing the samething as you discussed

 

Wow. This happened over a decade ago so my memory is a little fuzzy but I'm pretty sure it was because I reused a bunch of the snap rings when I did the rebuild and then again when I converted from lt1 spec to ls1 spec and one of them failed/stretched. I honestly don't remember for certain.

Has someone torn into your transmission recently?

 

what did you find? Was the clip broken on yours too for reverse shift fork?