i need some quick help. my trans am is in the shop out of town geting tuned so i can't pull the rear end apart for the numbr of splines.

i have a 86 trans am. does it have 28 splines or 26 splines or did they make both and it could be either and i'll have to open it to find out? or is it something else and i'm way off?

 

Its very likely you have a 10-bolt rear end with 26 spline axles.

 

how likely is likely? lol.

AND i have a built 383 with at least 453 hp and a 350 turbo trans. will that rear end with a pos traction unit be able to hang with that setup?
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and can i tell how many splines my rearend rearend has by the vin number?

 

If it's still the original 10 bolt diff then it has 26 spline. 28 spline axles were not used until 1990.

There's nothing stopping a previous owner from changing it over to 28 spline though so the only real way to know is to pull the axles and count the splines.

If you're sure it's still original then it will be 26 spline.

As for strength, V6 cars have broken diffs on the street and BBC cars have made them survive on the dragstrip. No matter how much to try to beef up the diff, it will still have the tiny ring and pinion and that will always be the weak link.

 

oops delete this one please, moderator sir/miss


double posted


haha

 

delete please thanks!!

 

well i've already bought the gears for the 26 spline so i'm going to go ahead and buy the posi unit and hope for the best. 465 tq. and 453 hp guarenteed. planning on bfg cheater slicks so loads of bite and torqe lmao. if things don't go well i'll just plant it a while longer and buy a ford nine inch fitted for it.

this was my first car, i bought it when i was 14 and althought i've had a long list of others along the way like a 65 mustang, 7 nova, 78 series land rover, 3 mr2's, two del sols, (one of which being an actual right hand drive jdm while i was living in england) i've never got rid of my trans am and now i'm fixing it up the way it should have been made stock.... bad ***!

 

hey there
yeah you have a lot of horsies to put through that rear

id would run it until a problem occurs then worry about it then

what year nova!? i love the novas i have had a few myself

i practically grew up in a 78 2 door one

i drool over them

you most likely have 26 spline unless it is a 90-later

you could always swap to 26 spline spider gears if you really needed to

any other axle, such as a 9" and so on are high dollar when they are modified to fit these cars especially

its insane

and is why most ppl run stock axles

most ppl never have a problem but one every now and then breaks due to power stress/failure

im surprised it is not more common to occur hehe

but this 7.5" axle was used under bilions of other vehicles, even the big caprices 90% of the time

always hold up

i did have one separate under a stock 79 caprice classic 305 2bbl and 200c

it was 2.41 ratio such as the one under the 85 supreme i just took to the shredder yesterday


horrible ratio for nay performance whatsoever haha
bad

the axle tubes came out of the center housing

the weld plugs broke

dont know why or how

it wasnt cuz the 305 2bbl was powerful, thats for sure hahaha


i have to blame it on faulty welding

never seen it happen before or since


the axle had a curve to it, it the third member was slowly getting closer to the ground haha

i put another axle under it from another car and it was fine since, until the 200c toasted on the rogers turnpike in oklahoma during a long trip to my aunts place down there



hope any of this info helps from us


good luck!