upgrading to 31 spline carrier and axles
- Thread starter D347643
- Start date
TIMMY2734
Founding Member
Michael Yount
Mustang Master
In order to fully put the power/torque to the ground, you've got to have traction -- in other words, if the car won't hook, the rear end/axles won't see all of that torque you're gonna be makin'. The tires act like a fuse - when they spin, the rear end/axles assemblies get a break. If you're not gonna run slicks, I doubt you'll have to worry too much about going with aftermarket axles because I think you'll spin the drag radials before you hurt the 31 spline axles. My car has more power/torque than the stock Volvo rear end is rated to handle, but I also have very limited tire space in the rear. I can only run 225 section tires - the rear end has been in the car for 8 years and about 20,000 miles because the tires spin before enough torque is transmitted to hurt the rear end.
I'd spend my money elsewhere -- once you've got the 31-spline carrier in there, switching the axles isn't that big a deal. If you find you're twisting the stock 31-spliners, you can always upgrade then. But unless you go to slicks, I doubt you'll have a problem. In any event, with slicks, the heavy duty rear end/axles and 450HP - hard launches are probably gonna require that you make some suspension and structural changes too - stronger control arms and reinforcing the control arm/chassis mounting points. So with traction, axles won't be the only potential weak point. Funny how that works, you fix one weak link, the next weak link shows up.
I'd spend my money elsewhere -- once you've got the 31-spline carrier in there, switching the axles isn't that big a deal. If you find you're twisting the stock 31-spliners, you can always upgrade then. But unless you go to slicks, I doubt you'll have a problem. In any event, with slicks, the heavy duty rear end/axles and 450HP - hard launches are probably gonna require that you make some suspension and structural changes too - stronger control arms and reinforcing the control arm/chassis mounting points. So with traction, axles won't be the only potential weak point. Funny how that works, you fix one weak link, the next weak link shows up.
Michael Yount
Mustang Master
D - here's the way it will work; you'll nail down the weak links in the drivetrain, then you'll want more power. Then, it starts all over again. 
It's only money.
It's only money.
89MustangGX
I have nothing productive to add!
Michael Yount
Mustang Master
You know 89, you're the wise one in all this. Since the Stang didn't come with a 31 spline diff, I think my whole response, while technically correct, doesn't amount to a hill of beans. Cause I don't think there are any "stock" 31 spline axles that will work. The stock axles that will fit the diff are for trucks - unless the whole rear end was swapped, they'd have to be modified to work - and that wouldn't be worth the trouble when you could just buy new tougher 31 spliners. Good catch. So, d34 - you gotta buy new axles anyhow. So all that crap I spewed before, well, never mind. Seems that I'm the one that has nothing productive to add.
Michael Yount
Mustang Master
Don't know about the Cobras - but if that's true, I gotta think they'd be awful hard to come by. Even from wrecked cars, people are gonna snag the whole rearend don't you think?
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