Posi
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Ok, so thats settled, the 7.5" rearend was probablly swapped into the '77 then.
Just to make absolutely sure, all carriers in GM 7.5" rearends swap no matter what the year. And the centersections don't differ based on axle length either.
Thanks for the help guys, I just want to make sure it works before I pull it.
Just to make absolutely sure, all carriers in GM 7.5" rearends swap no matter what the year. And the centersections don't differ based on axle length either.
Thanks for the help guys, I just want to make sure it works before I pull it.
The only difference the year will make is that in 88' or 89' they started using 28 spline axles. If you got one of those you can still you use it by getting axles out of an 8.5 g-body rear(we no how often you come across those), or by buying aftermarket axles for the above mentioned rear, at a cost of 250+. The only time I would consider this is if i was trying to use the zexel rear out of a 94+ f-body. I guess what i'm saying is if you're looking for cheap, stay with a 87' or older. :lol:
Alright, so this posi carrier will work. After the carrier and gears are out, are the axles visible so I can make sure its a 26 spline?
Sorry for all the questions, I 'm kind of noobish when it comes to rear diffs
Also what series is 2.41? I will be running 3.42 gears, can I just order a spacer from summit to run the 3.42 gears?
Sorry for all the questions, I 'm kind of noobish when it comes to rear diffs
Also what series is 2.41? I will be running 3.42 gears, can I just order a spacer from summit to run the 3.42 gears?
I had this question about 2 months ago and Jim helped alot. I also have a friend who worked for Eaton as a national sales manager and he helped also.
My son's 1978 wagon SBC (323hp and 410 ft. lb torque) had an open rear end, 26-spline. Having put a 700R4 in it we knew that would be dumb.
Between the Eaton clutch type, the Auburn cone and the Tru Trac, the recommendation was a Tru Trac. So I called Jim and he had one. We bought it and installed it. Couldn't be happier. It lays it down.
My friend from Eaton puts the units in this order: Tru Trac, Eaton Posi and then the Auburn. He really doesn't care for the cones.
Note: If you use a Tru Trac do not use posi fluid additive. We put it in cause we assumed it was needed by our Eaton friend says that posi additive is like "Sand" to the Tru Trac and we took kit out and cleaned everything. Sure enough there was some metal "stuff" in the fluid, but we had only driven it under 100 miles.
Jim knows his stuff and can help you. He did us. :wink:
My son's 1978 wagon SBC (323hp and 410 ft. lb torque) had an open rear end, 26-spline. Having put a 700R4 in it we knew that would be dumb.
Between the Eaton clutch type, the Auburn cone and the Tru Trac, the recommendation was a Tru Trac. So I called Jim and he had one. We bought it and installed it. Couldn't be happier. It lays it down.
My friend from Eaton puts the units in this order: Tru Trac, Eaton Posi and then the Auburn. He really doesn't care for the cones.
Note: If you use a Tru Trac do not use posi fluid additive. We put it in cause we assumed it was needed by our Eaton friend says that posi additive is like "Sand" to the Tru Trac and we took kit out and cleaned everything. Sure enough there was some metal "stuff" in the fluid, but we had only driven it under 100 miles.
Jim knows his stuff and can help you. He did us. :wink:
G80 is just GM's RPO code for some sort of real 2wd (not open). Most trucks with that code are lsd but some are true lockers. Most cars on the other hand are all lsd.
G80 = no good for any large amount of power or mileage. Most heavy duty GM trucks get rid of their rear ends around 150,000 miles. There were actually zex. torsen units used in trucks, not sure which ones though (light trucks). But you could just buy a nice worm gear driven detroit true trac for all the effort of finding and pulling an old torsen.
I personally wouldn't buy any old gm posi unit unless it was going on a cheap junk build. Just spend the extra few hundred bucks and get a nice carrier.
...btw a torsen and truetrac aren't true posi's and they last much longer
G80 = no good for any large amount of power or mileage. Most heavy duty GM trucks get rid of their rear ends around 150,000 miles. There were actually zex. torsen units used in trucks, not sure which ones though (light trucks). But you could just buy a nice worm gear driven detroit true trac for all the effort of finding and pulling an old torsen.
I personally wouldn't buy any old gm posi unit unless it was going on a cheap junk build. Just spend the extra few hundred bucks and get a nice carrier.
...btw a torsen and truetrac aren't true posi's and they last much longer
3XBrownCutty said:
You will have to pull the axles out in the process of taking the carrier out. So ya you will be able to count the splines to be sure. The 2.41 would be a 2 series while the 3.42 is a three. That is exactly what the spacer is for.
The other carriers being talked about are great, but before i spent 400+ on a new posi unit, and/or 250+ on axles, and more on new bearings, I would be ditching the 7.5 and starting with a better rear(8.5, 9", 12 bolt) first.
I hope i'm helping and not just confusing. 😛
Amen to staying away from the used GM units. My friend from Eaton related the same advice and here's the story he told.
When GM was developing the new Z06 Vette and the supercharged one, GM asked Eaton for a posi unit at a lower price. Having been beaten up for years on price, they wanted to know what GM was thinking. The response . . . $100 per unit. LAUGHHHH!!!!!!!! They did, but had to really dumb it down.
Buy a unit from Eaton (Summit, Jegs, etc.) as it will be the true unit. Is that ridiculous or what?
Our experience with Eaton's recommendation for the Trutrac was great. It lays down both tires and they like that the best internally.
When GM was developing the new Z06 Vette and the supercharged one, GM asked Eaton for a posi unit at a lower price. Having been beaten up for years on price, they wanted to know what GM was thinking. The response . . . $100 per unit. LAUGHHHH!!!!!!!! They did, but had to really dumb it down.
Buy a unit from Eaton (Summit, Jegs, etc.) as it will be the true unit. Is that ridiculous or what?
Our experience with Eaton's recommendation for the Trutrac was great. It lays down both tires and they like that the best internally.
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