Aligning factory T56 Bellhousing

**SSlowBoat** · 02-09-2017, 08:14 AM

Ok, so I have been doing alot of reading, since i always have owned automatic lt1's. I see many many many recommend strongly with manual transmissions in general, especially T56 cars due to the roller bearing to align the bellhousing properly. But with these cars specifically, I dont see anyone really doing it UNLESS they have a mcleoud or quicktime bell.

How many of you guys actually did or do a proper bell alignment with your t56, or do you all just shove em on, and how concerned should i be if i do infact just shove it on. a magnetic base dial gauge is cheap on amazon, as are offset dowels to bring it in spec if its out.

just basically looking if you guys do it or say NAY!! and slap it together

**Sahara54** · 02-09-2017, 10:23 AM

LT's I've never aligned, LS's I only measured for throwout bearing clearance.

**SSlowBoat** · 02-09-2017, 10:29 AM

Originally Posted by Sahara54

LT's I've never aligned, LS's I only measured for throwout bearing clearance.

I just don't wanna trash the input shaft with a roller bearing by not aligning it

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**96z28SideSwype** · 02-09-2017, 10:34 AM

Every time I've pulled one which is in total 4 twice on my daily and 1 for my dad and 1 on my other camaro we never aligned it, didn't know you were suppose to, they usually have a dowel pin on one side of the block or on the bell housing.

**SSlowBoat** · 02-09-2017, 10:59 AM

Originally Posted by 96z28SideSwype

Every time I've pulled one which is in total 4 twice on my daily and 1 for my dad and 1 on my other camaro we never aligned it, didn't know you were suppose to, they usually have a dowel pin on one side of the block or on the bell housing.

Those are standard dowel pins. They are not perfect, manufacturing tolerances vary and molds wear. Gm decided it was worth the warranty claims to not spend time on assembly line aligning them. There's some good articles online about 3 blocks from the same run that were outside the standard max deviation of .0025, from the same manufacturing time, hence this post. Could explain why so many people I've read toast roller pilot bearings and go to bushings, even though tremec says flat out not to.

Motor has standard dowels now. I think I'm gonna check it to be safe. I'm ocd and I can't afford problems.

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**96z28SideSwype** · 02-09-2017, 11:21 AM

Yeah with doing 4 times I've only had 2 bearings go out on my camaro and one was the throw out bearing snapped on me lol, the other was a pilot bearing but that was before I had ever pulled the trans my self it got replaced with a bushing then I replaced the clutch and swapped it back out for a bearing and its been fine ever since so I dont know if i just had a freak bearing or what.

**Injuneer** · 02-09-2017, 12:21 PM

I pulled my trans/bell housing and reinstalled it (when the car was still a T56), helped LT1 friends at least 3 times, and all cases, in my ignorance, relied on the dowel pins.

**Catmaigne** · 02-09-2017, 12:51 PM

It's a total pain in the ass. I didn't do it when I initially put my Mcleod on my cam-only stock motor and had shifting issues up top. When I got the 383 from Karl, I decided to align it properly (especially because the motor had been line honed for new mains) but there is no centering bore in the Mcleod. I bolted the bellhousing on the motor, pulled the front plate from the T56, set the magnetic base on the back of the crank and bolted the front plate over it so a bit of the base was sticking out through the input shaft hole. Then I clamped the dial on the base from the outside and used the input shaft bearing bore as a reference while spinning the crank. The geometry isn't perfect measuring this way but it gets the job done and will allow you to adjust the dowels until everything is centered.

AFAIK, I never had problems with the stock bellhousing alignment but checking it isn't that hard if you already have everything out of the car.

**SSlowBoat** · 02-09-2017, 04:03 PM

Originally Posted by Catmaigne

It's a total pain in the ass. I didn't do it when I initially put my Mcleod on my cam-only stock motor and had shifting issues up top. When I got the 383 from Karl, I decided to align it properly (especially because the motor had been line honed for new mains) but there is no centering bore in the Mcleod. I bolted the bellhousing on the motor, pulled the front plate from the T56, set the magnetic base on the back of the crank and bolted the front plate over it so a bit of the base was sticking out through the input shaft hole. Then I clamped the dial on the base from the outside and used the input shaft bearing bore as a reference while spinning the crank. The geometry isn't perfect measuring this way but it gets the job done and will allow you to adjust the dowels until everything is centered.

AFAIK, I never had problems with the stock bellhousing alignment but checking it isn't that hard if you already have everything out of the car.

I figure I can put the flywheel/clutch/bell on and align it on the k before sliding under the car

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**birdie2000** · 02-09-2017, 07:05 PM

Originally Posted by Catmaigne

It's a total pain in the ass. I didn't do it when I initially put my Mcleod on my cam-only stock motor and had shifting issues up top. When I got the 383 from Karl, I decided to align it properly (especially because the motor had been line honed for new mains) but there is no centering bore in the Mcleod. I bolted the bellhousing on the motor, pulled the front plate from the T56, set the magnetic base on the back of the crank and bolted the front plate over it so a bit of the base was sticking out through the input shaft hole. Then I clamped the dial on the base from the outside and used the input shaft bearing bore as a reference while spinning the crank. The geometry isn't perfect measuring this way but it gets the job done and will allow you to adjust the dowels until everything is centered.

AFAIK, I never had problems with the stock bellhousing alignment but checking it isn't that hard if you already have everything out of the car.

I had the McLeod SFI housing and I actually called McLeod about this as well as my transmission builder (very well known). The gist of both calls was that I should, but the bellhousing doesn't have provisions for this and most people don't.

I wouldn't worry about it on a stock engine with the stock bellhousing. My engine was line bored plus the aftermarket McLeod housing and I ran as-is and didn't experience any problems. YMMV.