in the states we (educated car owners)strive for 30000 miles for the tranny and diff change(i realize tranny means cross-dresser, not transmission, but dont care)

im coming up on 30K and i was wondering what type of oil you used as well?

this id for the transmission and rear diff.

steve

 

The book figure is 30,000 I personally change it more often than that, especially if the car still has the original, factory fill. There could be some particals in there! (hence magnetic drain plug!)
A popular 75w/90 is Castrol Driveline (AKA Syntrax) This is a semi-synthetic fluid. There have been some issues with synchromesh performance when using full-syn. although some have no problem.
JohnD

 

I'm lucky if if the gearbox lasts 30k miles, so the oil looks after itself

 

Roger Clark Motorsport just put Silkolene Silktran Syn 5 in my WRX last week.
http://www.opieoils.co.uk/performanc...04%20Wheel.pdf
Gotta say the gearbox feels better for it, although i dont know what was in before though. Feels smoother when cold and so better than before. Not tried anyother to comment on it.

 

JohnD What are the issues with fully synth then?

 

I tried Syn5 in the box of my 99MY when I had it and found that it would crunch changing 4th to 5th above 4000rpm. A number of others on here had similar problems. In general everyday driving the gearchange was fine. I changed to Castrol Syntrax and the problem disappeared. In simple terms, it seemed the "slippy" full-synthetic Syn5 didn't allow the synchro to "bite"
I would love to try it in my 6-speed STi box but 4.5 litres of fluid is a lot of money to risk!
The Syn5 went into the wifes Primera and works a treat!
JohnD

 

I've got fully synth in my MY01 gearbox and it's very reluctant when cold and the third gear is very notchy.
Wasn't like it before I changed the gearbox oil so may change it again next service for some syntrax.