Truetrac fitment?

WanaBa442

WanaBa442

Greasemonkey
Aug 5, 2017
200
316
43
New England
#1
So, was poking around Summit and peeked at the listing for a posi: https://www.summitracing.com/parts/dtl-912a317
Looking at the "customer questions" I see they say it'll fit a Monte Carlo, but not a Cutlass 7.5??
Unless you plan to run the stock 2.oh-too-low gear set, why wouldn't it fit the Cutty rear?
Spline count? That's all I could think of...….
This, with a set of upgraded axles, would handle a couple hunnert ponies OK.
 
pontiacgp

pontiacgp

Canadian Prime Minister
Mar 31, 2006
24,750
10,212
113
Kitchener, Ontario
#2
Thy have their applications screwed up

Axle Model: GM 7.5 in.
Axle Location: Rear
Make: PONTIAC
Beginning Year: 1988
Ending Year: 2002
 
WanaBa442

WanaBa442

Greasemonkey
Aug 5, 2017
200
316
43
New England
#4
So, which one would this be?
Listed as a 7.5 GM ( was in a 93 Firebird 10 bolt) but doesn't look like the Eaton catalog choices??
 

Attachments

79 USA 1

79 USA 1

Master Mechanic
Sep 2, 2011
425
542
63
Cheektowaga, New York
#5
pagrunt

pagrunt

Comic Book Super Hero
Sep 14, 2014
3,784
4,304
113
Shelocta, Pa
#6
Looking at the "customer questions" I see they say it'll fit a Monte Carlo, but not a Cutlass 7.5??
Unless you plan to run the stock 2.oh-too-low gear set, why wouldn't it fit the Cutty rear?
For some odd reason in the aftermarket world they don't know that a Cutlass is the same A/G as the Monte & the other A/G cars. It's our own little conspiracy in the world.
 
WanaBa442

WanaBa442

Greasemonkey
Aug 5, 2017
200
316
43
New England
#7
Oooooh, a secret society of a G-body sub-cult!!:wtf:
Cutlass Brotherhood, Unite!!!
Ruled by the High Command of the 442,
we lowly 7.5 plebians vow to aspire to 8.5 greatness........

SO, that said, I need to see what spline count this thing is..
 
79 USA 1

79 USA 1

Master Mechanic
Sep 2, 2011
425
542
63
Cheektowaga, New York
#8
SO, that said, I need to see what spline count this thing is..
Spline count refers to number of splines on the axle end which mates with the carrier you purchased. If what you have is from a 93 Firebird it should take 28 spline axles, Your Cutlass would have 26 spline. You need new axles!


When I installed a Detroit Locker in my 79 Monte Carlo I used a pair of 28 spline KA axles from Tom's Differentials. Should be the same as the 28 spline axles used in the 442 and Grand National 8.5"s
 
Last edited:
WanaBa442

WanaBa442

Greasemonkey
Aug 5, 2017
200
316
43
New England
#9
Yeh, axles would be part of the package. New bearings etc, just need to decide if the carrier series will support my ratio choice with a TH350...
 
xylorex

xylorex

Apprentice
Aug 2, 2018
77
46
18
New Orleans, LA
#10
i'm doing my rear end next, this is my parts list. this should be close to what you're trying to do.

moser A102801 28 spline axles
detroit 912A317 truetrac
Richmond Gear 83-1016-M Differential Mega Kit
Richmond Gear 49-0046-1 3.73 Ring And Pinion
aluminum cover --- havent decided on this one yet
 

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