Differential fluid change in 1994 Q45

[AlabamaDan]

I changed the gear oil in my differential tonight. The old stuff wasn't too bad, but needed changing and I wanted to switch to synthetic. While it was another pretty easy task, I do have some problems. The FSM calls for 1.5 liters. I realize it was probably the tilt of the car, but I ended up putting about 1.75 liters in. Is that a problem?

Also, I bought Valvoline Full Synthetic. Now another slip. I thought all the bottles I bought were 75w-90, but one was 75w-140. So I've got 1 liter 75w-90 and 0.75 liters of 75w-140. Is that a problem?

[qship96]

Fill level shouldnt be a problem as there is a vent on the top of differential,only negative I can think of is if you are parked on a real steep slope, some fluid may ooze out the top vent til level goes down a bit{but I doubt that will happen with the slight overfill you have}

easy enough to loosen fill plug while car is level and let excess spill out{spec calls for filling until fluid reaches the fill opening}

Mixture of 2 viscosities shouldnt be a problem either, slightly thicker when hot-same 75w when cold

[AlabamaDan]

Thanks. I didn't think it was a big problem, but wanted to check with everyone. BTW, here's the stuff I used:

http://www.valvoline.com/pages...ct=58

It was almost as expensive as the royal purple and I thought the royal purple might just be marketing and hype.

[maxnix]

I have used RP, M1, Amsoil mostly in 75W-140. All were good at 30K miles.