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Why a 5.0 driveshaft will not fit a 3.7?

15K views 22 replies 9 participants last post by  Siber Express 
#1 ·
So, after much deliberation, (and another failed trac-loc causing drama at VIR), I am going back to a T2R. While I am in there, I am going to go ahead and swap to 3.73s. My only issue with this is that I need a driveshaft that will not fly apart at 8,500-9000 RPM (it is attainable with my next round of changes). What I want to know is why people say that the factory 5.0 manual driveshafts do not fit.
 
#6 ·
I know a few guys that run an aftermarket GT 1-piece, but requires the GT's pinion flange.

Due to this reason, I'm assuming the GT flange makes up the distance that the GT shaft is "short".

Volt, I know you swapped pinion flanges, is the GT flange thicker than the V6 (Cobra) flange?
 
#8 ·
I had swapped over the flanges too because I was doing a whole rear end swap. So yes there's that aspect of it that won't allow a 5.0 drive shaft to fit on a 3.7.

3.7 has 4 bolts in the rear for ds to flange.
5.0 has 6 bolts in rear for ds to flange.

And also too short.


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#10 ·
Yea, transmission side is the same. Driveshaft just ended up being too short to fit on the v6 for some reason (could be because v6 was auto and I think the v8 drive shaft was from a manual but not 100% sure if it was from a manual) and this was after swapping flange


Instagram: @v6beast
 
#11 ·
So I should probably elaborate a bit. By 8,500-9,000 rpm, I meant driveshaft velocity, not engine. I have found someone who is going to let me borrow his driveshaft and flange at some point in the off season to do a test fit.
 
#13 ·
If you look under the car itself the transmission mount goes in a set of holes farther back on the GT then on the V6 so there's your difference in the length

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#14 ·
Much easier and less weight to just change to an aluminum driveshaft made for our V6's. Just my opinion :)
 
#16 ·
As many commenter already indicated, GT shaft is shorter. Here is my thought on the reason of the different.

Since the whole vehicle dimensions are same between GT and V6 but V8 engine has 2 more cylinders and longer than V6 engine, these 2 more cylinders each up some space and make drivershaft of GT shorter.

They might also have different diameter due to different load, but I think this probably isn't a problem.
 
#19 ·
I know there are 2 sets of holes for the Trans Mount, one for the V6 and the other for the GT, 2 inches difference making the GT shaft to short for the V6.
I know of at least 2 people that are running the Torsion rear end in their V6 with a GT shaft that had the front shaft lengthened to fit the V6, but they had to lengthen it to work.
 
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