GM 8.5" rear end spline count

[44boggers]

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

[87Flh]

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

[determined]

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.

[44boggers]

Originally Posted by determined

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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[Jay2Cor517]

If you decide to go the TrueTrac route you WILL HAVE TO order 30 spline count axles. https://www.summitracing.com/search?...ord=DTL913A481

[44boggers]

Originally Posted by Jay2Cor517

If you decide to go the TrueTrac route you WILL HAVE TO order 30 spline count axles. https://www.summitracing.com/search?...ord=DTL913A481

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

This is for a 28 spline 10 bolt 8.5"

[Jay2Cor517]

Originally Posted by 44boggers

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

This is for a 28 spline 10 bolt 8.5"

(Open mouth and insert foot or keyboard) Good catch 44boggers, I stand corrected. I simply should have stated the obvious, the 30 spline axle is stronger and would probably be a better choice for those who decide to change the ratio from the 2.73 to a 3.73 or numerically higher gear set with performance mods--more horsepower, bigger cam, trips to dragstrip etc.

[44boggers]

Originally Posted by Jay2Cor517

(Open mouth and insert foot or keyboard) Good catch 44boggers, I stand corrected. I simply should have stated the obvious, the 30 spline axle is stronger and would probably be a better choice for those who decide to change the ratio from the 2.73 to a 3.73 or numerically higher gear set with performance mods--more horsepower, bigger cam, trips to dragstrip etc.

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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