March 28, 2025, 07:45:31 PM

Author Topic: 8.8 diff flange sizes  (Read 1765 times)

Offline 346fc3s

8.8 diff flange sizes
« on: April 23, 2012, 11:34:43 PM »
Just so other people don't make the same mistake I did. There are two different sized pinion flanges, the actual Cobra diff uses a 4.25" bolt pattern and the lincoln/t-bird diff uses the smaller 3.5" bolt pattern.  I didn't specify when asking Samberg for a driveshaft flange to go along with my 8.8 mount kit and he assumed I had a cobra diff.  Not a big deal and the parts aren't expensive but if you are swapping to an 8.8 just be aware and make sure you measure your diff flange and specify which one you have. 
'87 Turbo II 5.3/T56
'03 Ram 3500 diesel, tow rig
'04 RX8 track toy
'05 IS300 wagon- waiting for a v8

Offline BoostedLS87

Re: 8.8 diff flange sizes
« Reply #1 on: April 24, 2012, 02:01:22 AM »
Yea the cobra and some trucks use the larger one.  3 inches by 3 inches.  The smaller diff flange is on the reg mustangs and smaller 8.8s  2.5 by 2.5  bolt hole to bolt hole.   I made the same mistake, the grannys torque arm wouldnt go around the larger one.
1987 stock 5.3/T56...t78, E85 9.80@155.03
1995 Dodge 2500 12v 12.23@111.45

Offline andrewb70

Re: 8.8 diff flange sizes
« Reply #2 on: April 26, 2012, 06:15:18 PM »
It is always a good idea to measure the companion flange on 8.8 rear ends to verify what pinion flange is needed. The critical dimensions are the bold circle and the center register, which aligns the flange. The U-joint size is also important to keep in mind. As I recall, the stock Cobra pinion flange use a 1330 u-joint, but I bet you can get a 1350 flange as well.

Andrew
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