hey ive got an 84 z28 and i was trying to figure out what i have for a rear end. the guy i bought it from totally did up the engine, 310 hp, and i have posi in the back but i want to know what the ratio is. someone mentioned to me that my year of car came with some type of "gov lock" posi... i found these numbers stamped on the diff.

GM N

22522676

k 8 a()21

(or it was 22522878) hard to read

thanks in advance.. or tell me a site that i can check out.. thanks.

 

I don't know tranny numbers for sh*t, but is it an auto? I think all the V8 cars '83 and up got a 700R4. If its a 5 speed its a T5.

This is assuming its the original tranny. If the previous owner put all this work into the motor, he may have also put in something like a TH350 or TH400, but I would not count on that.

If its an auto, its probably a 700R4

 

OH ****!!! i didnt mean tranny i meant rear axel!!! hahahah oops!! sorry,

 

but what if its a standard its a 5-speed that i have

 

THe only way to find out what gears you have is pull the cover. Look and see if there are any numbers like 41:11 for 3.73 gears stamped on them. If not just count all of the teeth and divide.

 

There is a easier way. Jack up the tires, mark the driveshaft on the bottom, mark the wheels toward the bottom, and start turning the driveshaft. If it takes 2 and 3/4 turns of the driveshaft to get the mark on the tires pointing down again, its a 2.73. If it takes a little over 4 turns to get the tires to point down again, its a 4.11, 4 and 1/2, its a 4.56.

See where I am going? This is easier and less messy.

 

That will work but not be very accurate at all, go with the sure-fire method!

 

How is it not accurate?

 

i did the driveshaft thing, but i spn the tires to see how many times the drive shaft would turn. i think that i got 3 and 3/4 or soemthing. im not sure.

 

If you did it right, you have 3.73's.

 

well, when i would spin the tire, it took me 3 and 3/4 times to spin the tire to get the driveshaft to spin once. i think.. would it have the same effect if i spun the driveshaft, would i more then likely get 3.73? and thats good right.


Also, my rear end is really purple.. its also rusted but is it possible that it is getting really hot?

 

Your driveshaft spins faster than the wheels.

As for the purple color, try to get a pic, cause I have no clue ATM what that could be.

 

oh ****, i think i had it in first... or neural.. its a 5 speed. ill try to get a pic today or tomorrow

 

*Smacks forehead*

Try it again in neutral.

-edit- If you had it in 1st, you would have been turning the engine too, I dont think it affects the gear ratio.

 

dammit.. how much different will it be.

 

I dont think it does on second thought. If you did have it in 1st, it might have been a little harder to turn the wheels cause you were turning the engine too.

Trust me, mark both pieces and turn the driveshaft. Its easier to be more precise.

 

soo all i have to do is count how many times it takes to get the wheel to turn, when turning the drive shaft..

ie. i had to turn the driveshaft four times to get the wheel to turn over even once!!

 

Have you changed the fluid lately? Then you need to take the cover off anyway.

Just take the cover off and look; that way you'll know everything there is to know about it. What gear it is, what kind of posi if any, etc. And of course, when you get done, you'll have nice clean new synthetic fluid in it, with the GM posi additive if it needs it.

 

if i open it up, is fluid going to go all over me?? how do u drain it? and fill it? will i need a new gasket when this is over?

 

When I wipe my butt, will I get dirty??!?!

Won't I have to use TOILETPAPER?!?

Will one of you guys come over to my house and do it for me?

 

If you are directly under it, then fluid will go all over you. If you are off to the side, it will miss you.

You drain it by removing the cover. Loosen all the bolts, then take out all except the 2 top ones, save the 2 bottom ones for last, then loosen the 2 top ones a little more and pry the bottom of the cover off gently. Have a large pan under it to catch the fluid.

It uses the "tubular style" gasket.

 

:nono:

 

if you guys are worried about greater accuracy, just turn the wheels 10 times, and you should get 37.3 turns of the shaft. if you turn it 25 times, you get 93.25 turns, etc. but the error from 93 vs 93.25 is minimal, compared to measuring 3.08 to 1 turn vs 3.23 to 1 turn, etc

(btw, 93/25=3.72. i think 10x and being within 1/4 turn is more than sufficiently accurate.)

 

i thought the diff was filled with just grease.. no real liquidy stuff. so how the hell am i going to fill it back up again?! is there a fill hole, i thought i saw some kind of filling spot when i looked at it before.

 

Yes there is a fill hole. On the pass side, about halfway up. It's a pipe plug with a square drive, you just stick a ratchet in it to get it out. It's filled with about 90 weight oil... definitely liquid, but pretty thick, about like honey.

 

And by the way, the fluid STINKS LIKE POOPY.

 

 

great... ive decided not to do it, im just giong to get it dynoed and maybe throw in something BRAND new.. it looks like **** and new *** ends look sweet.