Companion flange problem
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Instructor
Joined: Jun 2001
Posts: 231
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From: Cedar City UT
Companion flange problem
I have a 67 vert with a "FA"rear end that has a companion flange about 3 1/2 " across. I'm in the process of putting in a new/used "OA" rear end ,out of a 76-77 vette with a companion or pinion flange about 4" across. The OA differential is suppose to be from a 76-77 rear end.
Does any one know if I can just swap these flanges or is there going to be a problem with the pinion splines being different. Am I going to have to replace the seal due to size or variation. The casting numbers on the cases are the same and this is the only difference I've noticed ,unfortunately ,after I installed the rear end in the car.
Also does anyone have a tricks for holding the flange and removing the nut without the factory tool.
Thanks Bob
Does any one know if I can just swap these flanges or is there going to be a problem with the pinion splines being different. Am I going to have to replace the seal due to size or variation. The casting numbers on the cases are the same and this is the only difference I've noticed ,unfortunately ,after I installed the rear end in the car.
Also does anyone have a tricks for holding the flange and removing the nut without the factory tool.
Thanks Bob
Last edited by Desertvette; Feb 16, 2006 at 08:33 PM.
Race Director
Joined: Feb 1999
Posts: 19,659
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From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
I am no help to you other than to tell you to send gtr1999 a pm and see if he can help you out. Or wait around and see if he will come across this thread. Gary is "The Diff Man" 
Tech Contributor
Joined: Aug 1999
Posts: 15,130
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From: Connecticut, USA
The differentials will fit,as you know the yoke needs to be replaced. The earlier 4 spd cars used a smalled U jointand yoke. The splines from the 2 should be the same, I think the 63-64 had a different spline. What you want to be careful with is not compressing the crush sleeve any more. If you have them both out of the car then you can check the drag on the bearings on them before the swap. You'll need a dial in/lb torque wrench with 0-30 scale. If you go to that post I ran on the differentials there should be more info and pictures to help. Not a big deal out of the car. Use #2 on the yoke spines too or it will leak.
