BUILD THREAD 86 GP 2+2~Blown 6.0

[81cutlass]

Got the main shaft and reverse gear delivered Friday and pressed the 1-4 syncros in. Put the main, input and counter shaft in to adjust the backlash and I didn't have any backlash on the countershaft. I think spec is 1-2 thou. I didn't touch anything in that shaft and it doesn't seem tight like it's in preload so maybe it's fine? I need to read into the shimming stage more.

 

[Supercharged111]

Countershaft needs a little preload, main and counter extension get no preload. Did you remove the shims then measure?

 

[81cutlass]

Countershaft needs a little preload, main and counter extension get no preload. Did you remove the shims then measure?

I didn't. I read into it and yeah, I gotta pull the shims and check. I had them installed when I checked and if they target -2 to +2 thou preload, and I don't see significant preload so I'm guessing it's really close.

 

[Supercharged111]

My Camaro box that had been rebuilt before I rebuilt it came out dead nuts with the shims that were in it. Whoever did it before me must have set it up with the broken in bearings. You're kinda starting over with a new main shaft plus if you changed any bearings. Like my Z06, I changed the main shaft and countershaft extension. Compared to the shims it had the thing was WAY off.

 

[81cutlass]

Checked backlash and preload and it was right on without touching anything. 1.5 thou backlash on main shaft and 2 thou preload on countershaft.

Siliconed the front housing/cover and fought to get all the shift rods aligned while trying to get the shafts through the bearing bores and the detent selector aligned simultaneously. What a PITA.

First time the 1/2 and 3/4 syncros fell into gear instead of neutral and got everything out of time. I didn't know, tried putting the guide pins in and nothing lined up, took it apart and ricocheted the decent ball across the garage. Searched for that and the silicone cured in the mean time. Scraped that off.

Take 2 the linkage tangs went out of time and I fussed with it for a while, silicone cured, had to pull the shift rods out and realign. Cleaned off silicone and had to make sure the detent ball didn't roll under the shelf again...

Take 3 I put the selector in reverse to lock 1-4 syncros in neutral and octopus'ed everything together and it finally went in time. Dropped the guide pins in and shifted through the gears and everything seems right. Thankfully!!!

So I gotta tackle 5-6 and reverse tomorrow. Might get in tomorrow evening if I'm fast but probably Tues.

 

[Supercharged111]

I fought that same battle a few months back. It sucks. Be CAREFUL with that 5/6/R shaft, getting it to seat in the tail housing. I pushed too hard on the tail housing and the 5/6/R rail knocked the 1-2 syncro into a gear and I was screwed when I put it into the car. Verify you have all 7 gears after installing the tail housing before sticking it in the car. I drop the tail housing down gently, then shove the 5/6/R rail around with a screwdriver until the housing drops on by itself.

 

[81cutlass]

I fought that same battle a few months back. It sucks. Be CAREFUL with that 5/6/R shaft, getting it to seat in the tail housing. I pushed too hard on the tail housing and the 5/6/R rail knocked the 1-2 syncro into a gear and I was screwed when I put it into the car. Verify you have all 7 gears after installing the tail housing before sticking it in the car. I drop the tail housing down gently, then shove the 5/6/R rail around with a screwdriver until the housing drops on by itself.

I'll keep that in mind.

Did you have the guide pins in place when you put the rear extension housing in? I put mine in as soon as I could so things didn't knock out of place. I might need to pull them back out and locktite them as they were OEM.

 

[Supercharged111]

I'll keep that in mind.

Did you have the guide pins in place when you put the rear extension housing in? I put mine in as soon as I could so things didn't knock out of place. I might need to pull them back out and locktite them as they were OEM.

Yes, guide pins go in as soon as possible. The off center one is easy, the other you have to lift on the 5/6/R rail and it pops right in.

 

[81cutlass]

Put the 5/6, reverse & tail housing on tonight. Goes through the gears well and didn't have any parts left over.

The new 5/6 and shaft pressed on pretty snug. Much different than the worn parts. Heated the 5/6 gear in the oven to 450 and used a pipe and hammer to get it installed. little hassle but not awful. It's not coming off easy!!

Got the trans sealed up and filled with oil. Cleaned the bench, painted the xmember and it's ready to install tomorrow evening.

 

[81cutlass]

Trans is back in and I took a short cruise and everything seems functional.

It doesn't drive much different but it's for sure easier to put in reverse and there isn't any mechanical cogging noise in 2nd or 3rd gear shifts so it's improved.

Hopefully it's a bit better when I start bang shifting the thing again.

Overall 10/10 would rebuild my own t56 again. Pulled the trans out on 8/21 and back in on 8/31. I took a few evenings off but otherwise 2hrs spread out over about a week and got it done. If you have a press and a couple snap ring pliers and a dial indicator besides some basic hand tools it's pretty straight forward.