what kind of tranny oil and differential fluid do I use for my car?

 

Regular, good ol' gear oil, 75-w90 does the trick for both. Some of the better shops recommend Redline or Royal Purple, along with GM 's LSD additive if you have a Clutch-type Limited Slip Differential (86-88 only). IIRC, only GXLs and TII's have a LSD.

 

i like to mix about 50/50 gear oil and atf in the transmission in a street car, it acts like synthetic, but its cheap and easy to find.

 

Unless you are Pounding the **** out of the car then the regular 75w90 or so will work just fine.
It's cheap and works.
Now if you want you can go Half and half with a Synthetic gear oil and a 75w90(which is really what they refer to as Semi-Synthetic) or Hop up to a full synthetic which in the long run smoothens out the "glitchy gears".
Honestly for a car that won't see the track or racing then just get something that works.Regular Gear oil.
On the rear diff you can add a "modifier" (Royal purple has it) If it is LSD.
If it's a "one wheel Peel" type diff then don't waste the money.

 

this is something i got hip to in the last few years myself.