Shifting into reverse in my 15K mile MN12 T56 (2005 GTO) continues to be a problem. Lockout solenoid works fine, it's almost like the gate is slightly off. No grinding or anything, just doesn't want to go in and requires multiple attempts. Same problem with multiple shifters I have available, and no real difference with car running or not. Engagement in all other gears is great. Called Rockland Standard Gear and Tick. Jeremy at Tick advised me to remove the extension housing / tail housing, and replace the reverse components. All reverser related components (fork, gear, syncho, bearings, etc) are about $350. I had the extension housing off years ago when I swapped the shifter cup and shifter from the GTO setup, and shipped to Alloy for a mechanical speedo mod.

Has anyone replaced the extension housing in the car? It would be great if I could leave the transmission in and not break the hydraulic setup and fight with the headers again. Thanks.

 

I think you have to open the main case to swap the fork, so you may as well just pull the trans

 

Pull the transmission, take advantage of having it out to install a remote bleeder line. Trying to do this in the car just creates other hassles. The trans will be angled down towards the rear causing a constant drain of fluid, this will make successfully resealing the mating surfaces difficult. There are a few things that have to line up in order to get the housings mate up. Having the trans on a bench using a fixture makes this much easier eliminating the effects of gravity. Trying to poke around and push rails and shafts into alignment with wet sealant on the case is avoidable. I am curious if your issue started after the last time you had the tail housing off? It kind of sounds like you may have lost one of the pads on the shift fork. Most importantly get a rebuild manual, it's $15 well spent.

 

Thanks guys. I have a remote bleeder installed now, although it's a Tick first generation bleeder without the check valve. Good advice on the repair manual, I downloaded and printed that this morning. I never drove the combination in the GTO before pulling it, so it's possible I did something wrong when removing and installing the extension housing for the mechanical speedo mod and shift cup replacement (GTO to F-body). I do recall it being tricky to install the housing even on a bench, had to push up lightly on the fork/shaft and not mess up the RTV. Once I get the trans in reverse, it goes in and out fine from N, but if I go to any other gear and back to reverse, it doesn't want to slide into the gate.

 

I know these trans' don't do this, but it almost sounds like the reverse lockout on some older ones, lol. I think my NV4500 won't let you put it in reverse unless you put it in 1st gear before, so you can't accidentally shift from 3rd or 5th or something then into reverse afterwards.

 

T56 have reverse lockout, mine works as intended. It prevents you from moving over to the reverse gate. My shifter moves over great - it just doesn't move forward into the reverser gear. To check this, I just push the shifter in the neutral gate all the way to the right and hold it, then turn the key on and instantly you can move it further to the right into the added reverse gate. I've also removed the solenoid to check for it's operation and if it affected the problem.

 

No, I understand, I have 3 T56s, it just almost sounds like the 1st gear lockout, lol.

 

So you pulled a 15,000 mile drivetrain from a wrecked GTO? The shifting into reverse issue probably comes from when the GTO was damaged? A 5 gallon bucket can be turned into an assembly fixture. The hole in the side would be for performing the shimming procedure if you were to get that involved. That hole only needs to be big enough to get your hand in there.