For T56 specialists

NicolaS W

NicolaS W

Not-quite-so-new-guy
Aug 20, 2015
33
54
18
South East of France
#1
Hi guys...
As my T56 was whining under heavy load in 2nd, 3rd and 4th gear I decided to disassemble to find what was wrong with it...
Currently I found nothing wrong wirth the bearings (they all look in good condition, transmission, comes from a 2004 pontiac GTO with less than 60K miles), except with the bearing races on the transmission front adapter plate. Bearing races are not fited tight in the plate... they're free... I reversed the plate and they felt down on the floor.... Can someone tell me if it's normal or not ?

 
TURNA

TURNA

Geezer
Jul 24, 2009
6,691
8,629
113
Socialist NY
#2
I have no idea about that plate but, I am pretty sure every outer race I have seen was always pressed in
 
xylorex

xylorex

Not-quite-so-new-guy
Aug 2, 2018
45
30
8
New Orleans, LA
#3
I agree with turna. The race must be tight in the housing or it could/will rotate in the housing and cause more damage.

I'll probably get a thumbs down for this but in my RC cars, sometimes if I'm in a jam I will use red loctite or super glue to keep the race stationary in the housing.
 
8

81cutlass

Royal Smart Person
Feb 16, 2009
1,541
2,036
113
Western MN
#4
I'm not a t56 expert, but I do design drivetrain parts for off road equipment for a living so I'll give it a shot.

Slip fit bearing races are common (almost mandatory) when you have a preload adjustment ring behind it. That side looks stationary so it should be press fit, but a transition fit (mostly press but a very light press is OK) isn't out of the question due to tolerance stack.

If the race can be wiggled back and forth and drops EASILY down, thats not right, possibly order another race and see if its tight or not. If it slips the bore diameter is oversize. Too much slop can affect your gear mesh pattern which is likely making the noise if its real loose. (.002 will feel loose but not affect the contact pattern much, .030 will feel terrible and will cause contact patch issues.

I doubt the race would be spinning and making noise. I dont know how or what the preload spec on a t56 is, the bearings and shafts could be in endplay, but i doubt that. If there is decent preload the race should be held and not spinning due to friction to the housing.

Anyways, if the race was spinning, it would make heat and the race would friction weld itself to the housing.
 
NicolaS W

NicolaS W

Not-quite-so-new-guy
Aug 20, 2015
33
54
18
South East of France
#5
Everybody seems to be right...

Turna, i agree with you...the races in the adapter plate are the only one that can move... all others are firmly pressed in.
Xylorex, I know this red Loctite... not a bad product ;)

81 cutlass, you're right to, there are preload setting shims under the races.... but the race can be moved only with hands... don't think it's normal too...
 
455'ed80Regal

455'ed80Regal

Master Mechanic
Nov 3, 2010
414
140
28
Lincoln, MO
#6
I would think that the outer race would need to have some sort of press fit in that aluminum cover. Don't think bearing preload alone will keep it from spinning. At least not for very long.
 
NicolaS W

NicolaS W

Not-quite-so-new-guy
Aug 20, 2015
33
54
18
South East of France
#7
Hi guys,

After diassembling the transmission, i found the 2nd gear needl bearing was not in great condition... it's not clearly visible but the noise it makes wan not the same than the others.
So i decided to order a full bearing set for the T56...just ave to wait for it now...:)
About the "free" bearing race in the adapter plate, from what i read on other forums, it seems to be normal...:cautious:
 
NicolaS W

NicolaS W

Not-quite-so-new-guy
Aug 20, 2015
33
54
18
South East of France
#8
HI guy.. few news from France...
I spent a ligt time rebuilding my T56... (few weeks wasted waiting for parts)... I changed all the bearings... According to me the main noise problem came from the bearing preload / end play settings... Now the transmission is not noisy anymore, I can hear the shifter rattling ( i'm not the only one, have a look on the web)....I now have to look for the reason the shifter is rattling, but if you also have a noisy T56 you may have a look to the shifter before rebuild it :LOL:
 
pagrunt

pagrunt

Comic Book Super Hero
Sep 14, 2014
3,398
3,706
113
Shelocta, Pa
#9
Just wondering, are you running the stock shifter or an aftermarket? Another thing is does the shifter need a plastic bushing for the shifter's "ball" for the internal gate like the T5? I'm not that up to speed of the T56 or T5 but those two areas might where to look. Being a worn shifter or bushing could be you noise.
 
NicolaS W

NicolaS W

Not-quite-so-new-guy
Aug 20, 2015
33
54
18
South East of France
#10
I have an aftermarket short shifter, with a new ball plastic bushing (installed when i rebuilt the transmission), but I wonder if the bushing is nit floatting in the housing, i have to check, it can make noise.
i also want to try with a OEM shifter....
 

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