9'' diff.yoke useage

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boilermaster

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michigan
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71 fastback
I am running a 71 FB with C4 trans (unknown ) and 9'' rear diff (no tag) 51'' driveshaft and with the car sitting I only have about 1'' of travel left till the trans yoke hits the tailshaft of the transmission.

the rear diff appears to have a long yoke that could be causing my concern.

It measures 4-3/8'' from front to rear of seal guard, would this be considered the long flange ?

Can this flange be replaced with shorter one with an unknown diff ?

What I know about the rear diff. so far.

9'' (cannot put socket on 2 lowest nuts) , standard case (only 1 vertical rib , pinion support (C5AW-4688-A ) securing bolt flanges all machined flat and bolt on snubber.

axle ratio believed to be 3.91 (aligned paint stripe thru fill hole and 1 rotation= almost 4 revolutions of the pinion flange.

the markings I found on the carrier 9D17, DIF 61 the circular stamping =13616

I do not intend to keep the 3.91 gearset, but this is supposed to be a locking differential, and I would like to rebuild it with perhaps 3.55 gears.

any information on what I have would be greatly appreciated.

Boilermaster

 
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I ran into this issue with a replacement carrier I bought. The simplest solution is to take your driveshaft to a shop and have it shortened and re balanced. Should cost about 75-100 bucks.

I assume you know that driving it, as is, could result in damage to the transmission case if the yoke bottoms out.

Also, the 3.91 gear set, to my knowledge, is not being made anymore-suppliers now make a 3.89 in its place. If the gears are in good shape upon removal, it might be worth something to someone into concours correct cars

 

boilermaster

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71 fastback
Ok,

Believe I am looking for a (1310 ) yoke for 28 spline , should measure

4.03'' overall and 3.219'' between the tabs and needs to be for 1-1/16'' caps , anyone got one they want to part with ?

Boilermaster

 
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