75w90 or 80w90 for rear diff

[Gecko123]

I read a few postings here about differential fluid and some of you use 75w90 for transfer case, rear and front diff, but the manual calls for 80w90 for the rear.

Is it critical to use 80w90 for the rear?

below is taken from the owners manual

TRANSFER
Oil capacity, L (qt., Imp. qt.):
1.4 (1.5, 1.2)
Oil type:
Hypoid gear oil API GL- 5
Recommended oil viscosity:
SAE 75W- 90

DIFFERENTIAL (4.0 L V6 [1GR- FE] engine)
Oil capacity, L (qt., Imp. qt.):
Two- wheel drive models
3.05 (3.2, 2.7)
Four- wheel drive models
Front 1.5 (1.6, 1.3)
Rear 3.05 (3.2, 2.7)
Oil type:
Hypoid gear oil API GL- 5
Recommended oil viscosity:
Front
SAE 75W- 90
Rear
Above -18!C (0!F)
SAE 90
Below -18!C (0!F)
SAE 80W or 80W- 90

 

[hearno]

I've read a few threads where people have used the 75 in the front, center, and rear but I didn't. The spec calls for 80 so I ponied up the extra bucks and got that.

 

[OzarkRunner]

I'm one of those that went with 75w-90 in all three. I changed it recently, and didn't see any cause for concern with that weight (shavings, color, etc.).

 

[fourwd1]

I wouldn't worry about using 75W90 at all, just make sure you get the proper GL# for each.