I bought my first A4 2 weeks ago (2001, 1.8, manual, 76k only) and friend of mine
suggested that I change oil in the gearbox, just to be safe.
I am going to change engine oil (Castrol Syntec 5W40), flush the cooling system this week, now is there any need for gearbox oil change? What about diff. oil?

Thanks

 

when it comes to dif oils it really depends if its a quatro version, then you might have to change it every 2 oil changes or so, at least in subaru world. When it comes to manual gear box, i dont beive you need to change it this soon! any one care to correct me?

 

Generally consider replacing Audi gearbox oils when over 100K KMs and most recommended by 150K KMs.

You will need a fluid pump to install new gearbox fluid. The center diff usually shares fluid with the manual trans housing so drain both, clean magnets, refill trans, drive car around the block or run through gears on hoist with ESP off and wait a few minutes / recheck fluid level / add fluid as level will have dropped.

Always double check for your particular vehicle but manual trans and diffs oil is likely 75W90 Full Synthetic Gear Oil.

 

Redline MT90 (GL4) is in the gearbox and Royal Purple (GL-5) in the rear diff.

Haven't seen any improvement (softer shifting), but it may take time?
The old fluid were very nasty though.