what's up yall, i just got a rear end, and i wanted to check my gear ratio. The code ive found is 2 cf p297n, and is this rear end a 7.5 or 8.5? thanks in advance

 

What kind of car is it?

 

sorry bro, for the late responds its a 1977 oldsmobile delta 88, 403ci

the code was on the passenger side (2 cf p 297 n)

i know the N stands for night, and 297 is the day of the year, and P is for pontiac, but i dont know what the 2 or CF stands for.

 

From what info that I have it appears to be a 3.08 rear end. The problem is my info is for the Cutlass/442 models (b-bodies) so I am not sure if the full size cars used the same codes for the gears.

 

yea thats what my cutlass book says too hope it apply with full size years too, is that 7.5 0r 8.5?

 

anybody else got some input on the CF code on my rear axle?

 

I need a picture of the rear to tell if it's a 7.5 or 8.5
.

 

ok what gear ratio you guys think it is?

 

Probably a 2.41:1 if it's from a 77 Delta 88.
My 77 Grand prix rear came with 2.41 posi. My 77 Delta pacecar rear came with 2.41 posi, and all my 80's deltas came with 2.41 open.

 

i got it from a wreaking yard already pulled, so dont know what car they pulled it from. i thought these codes on the rear axle i gave up would tell me, more about the differential..thanks

 

Codes are only worth a crap if you have the book to decipher them.
It's easiest to unbolt the cover and look.
Only 1/2 hour to scrape & replace the gasket.

 

Is there a reason you can't just turn the hub once & count the pinion turns ?

 

Because a 3.23 gear would be 3 1/4 turns, 3.42 about 3 1/2, 3.55 about the same. too hard to tell. The difference between 32 1/4 rotations and 34 1//2 would be much more obvious.

 

That is what i was thinking....

 

thats what i had the differential shop do, i was just checking out the other threads, before i made this thread and most people was just using the code off the rear end, but no problem, rearends is not my thing, so ill leave it alone..thank guys for checking up with me

 

will that still work if gears is grinding?

 

thats well explained, will remember this thanks