GM 8.5" rear end spline count
 

Hey guys,
I need to order up a truetrac and new gears. Did our trucks all come with 28 spline count shafts? I had it apart two years ago and I can't remember. I feel like it was 28 spline. I think from 1989 and up is the 30 count spline. Can anyone confirm?
I know I'm being lazy by not pulling it apart, but I'm in paint and body work mode now and dont need extra oil around the small garage at this point.

Thanks

Paul

Re: GM 8.5" rear end spline count
 

Should be 28. Only one way to know for sure though.

Re: GM 8.5" rear end spline count
 

You are correct but given how many complete diff's I have swapped into those trucks over the years I would not take the chance ordering the parts without checking it first.

Good chance you are going to need an axle, speedy sleeve or an offset repair bearing or two.

Check it over and do it once.

Yeah I needed to stop being lazy about and just do it. 28 spline count it is.

Thanks for the motivation guys
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Re: GM 8.5" rear end spline count
 

Re: GM 8.5" rear end spline count
 

https://www.summitracing.com/int/par...a556/overview/

This is for a 28 spline 10 bolt 8.5"

Re: GM 8.5" rear end spline count
 

Yeah I duly understand. Normally I would have done this but I have a different situation than most. I’m building this in Europe so I am relying on people to bring parts over to me since shipping plus inport fees are crazy high. So asking to bring some axle shafts on top of the locker and gears and all my other stuff is not really possible. I won’t have Crazy hp either as it’s a build 305 with power numbers probably in the low to mid 300’s and torque not any higher.

But you are correct. 30 spline axles would be better.
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