i recently bought a 86 t/a and it has a 9 bolt i was wondering if anyone knows what gears are likely to be in my car it is a auto 305 tpi i am building a motor for it now check out my other threat "engine build how much power"

 

Most likely a 2.73 ir 3.27.
I believe mine had a tag on it that was stamped 3.27.
There is an unbeliveable post on the 9bolt here, I believe in Tech/General.
You might want to search there.
Ron

 

ok thanks alot i did look for a tag but it was already removed i guess

 

Did you check the RPO codes under the console lid?

 

are you sure its a 9-bolt?

9-bolt was only available in the 350/auto in '86 as a 3.27 ratio. 305/auto got a 10-bolt 2.73 or 10-bolt 3.23 with G92

 

yea it is a 9 bolt. and i always thought that they never relesed any 350tpi cars in 86. i thought only like 50 or so were made for test cars

 

Chances are, a gear oil change is long overdue on that 9 bolt. If you go ahead and change the oil, which requires removing the rear cover (easy), you should be able to find the ratio scribed somewhere on the ring gear. Worse case, count the teeth on the ring and pinion and do simple division. Do not be afraid to pull the cover, it is a very easy job.

 

Jack up the rear end with both wheels off the ground (in case you have a posi unit) Use jack stands, block the front tires.

Mark the driveshaft. Have your buddy turn the rear wheels one complete turn. Count how many times the driveshaft went around.

If one turn of the wheel axle gave you 3.5 turns of the driveshaft, you have 3.50 gears.

 

also on the front of the gear housing on the bottom it will said "borg warner" if its a 9-bolt