. I have a WR T10 trans.
Diff swap
Thread Starter
Instructor
Joined: May 2005
Posts: 222
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Diff swap
I'm looking to replace the differential in my 77 (maual trans) with a diff from a 74 big block vette with atuo trans. Will this work? I'm looking to use the 74 diff complete with side yokes cover and mounting bracket.
Any comments are appreciated.
Any comments are appreciated.
Melting Slicks
Joined: Feb 2003
Posts: 3,053
Likes: 4
St. Jude Donor '03,'11
all the iron diffs take 3350 joints in the side yokes. Some have heavy duty side yokes and some with straps.
Gary is the expert but i think the heavy duty side yokes come with a pinion that accepts 3330 joint but, when set up with the light duty side yokes the pinion accepts 3310 joints.
If you have a miss-match there are 3310 to 3330 joints available. I did this at one time.
Gary is the expert but i think the heavy duty side yokes come with a pinion that accepts 3330 joint but, when set up with the light duty side yokes the pinion accepts 3310 joints.
If you have a miss-match there are 3310 to 3330 joints available. I did this at one time.
Race Director
Joined: Aug 1999
Posts: 18,126
Likes: 174
From: WI
Originally Posted by gtr1999
It will bolt up but 390 is a Richmond gear. They are known for noise - doesn't mean anything but keep in mind someone was in there before.
without looking how do you know it`s not a GM gear?????
...redvetracr
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Tech Contributor
Joined: Aug 1999
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From: Connecticut, USA
Red,
GM never used a 390 gear in a vette. Richmond is the only one I'm aware of that uses a 390 gear.
Turtle,
I have not rigged up a way to run a diff off the pinion. It can be done.
I was thinking of an old lathe with a coupling between the headstock and pinion. Mounting the diff to a plate to set the pinion at the correct angle then running. Thing is you would also have to setup some type of brake on each yoke so you can simulate road load. This is a lot of work and I'm no one in the business is doing this.
I made a fixture to rotate the ring gear by hand at final assembly to check for feel and noise. Again this is in a no-load situation.
GM never used a 390 gear in a vette. Richmond is the only one I'm aware of that uses a 390 gear.
Turtle,
I have not rigged up a way to run a diff off the pinion. It can be done.
I was thinking of an old lathe with a coupling between the headstock and pinion. Mounting the diff to a plate to set the pinion at the correct angle then running. Thing is you would also have to setup some type of brake on each yoke so you can simulate road load. This is a lot of work and I'm no one in the business is doing this.
I made a fixture to rotate the ring gear by hand at final assembly to check for feel and noise. Again this is in a no-load situation.
Race Director
Joined: Aug 1999
Posts: 18,126
Likes: 174
From: WI
Originally Posted by gtr1999
Red,
GM never used a 390 gear in a vette. Richmond is the only one I'm aware of that uses a 390 gear.
GM never used a 390 gear in a vette. Richmond is the only one I'm aware of that uses a 390 gear.
At one time GM offered a 3.90 (3970551), a 4.56 (3961424), a 4.88 (3963840) and even a 5.14 (3970552) all sold "over the counter" for the Corvette.
.......redvetracr
Tech Contributor
Joined: Aug 1999
Posts: 15,114
Likes: 3,909
From: Connecticut, USA
Originally Posted by redvetracr
Gary,
At one time GM offered a 3.90 (3970551), a 4.56 (3961424), a 4.88 (3963840) and even a 5.14 (3970552) all sold "over the counter" for the Corvette.
.......redvetracr
At one time GM offered a 3.90 (3970551), a 4.56 (3961424), a 4.88 (3963840) and even a 5.14 (3970552) all sold "over the counter" for the Corvette.
.......redvetracr
I stand corrected on that, I suppose if I dug out my GM pef part book they would have been listed. For a production car 390 were not offered. I do remember the 456 and 488's. My buddy went from a blown 411 set to 456's for street driving! Never used GM 390 or 5.14 gears.
Now since this unit was probably built by a local shop or garage I'd be willing to bet they are still Richmonds- just for the availability and cost of them. Now we must know!!LOL
Red, I'll buy you lunch if they are GM gears!
Last edited by gtr1999; Nov 11, 2006 at 11:32 AM.