Gearbox crunching into gear

[bertman]

Darren that has crossed my mind the fact I need something thicker perhaps
What would you recommend as a good alternative??

[Error404]

with Darren, what oil is it you're using Rob?

[bertman]

Millers fully synthetic 75/90

[Error404]

What spec? is it GL-5? If so that could be your issue.

[bertman]

Right Alex got the can in front of me and it says API GL-4,GL5

[Error404]

If the crunches started shortly after the new oil went in then that is probably most of your problem.
I made the mistake of filling mine with GL-5, Rob (GT500) told me it wouldn't work and he was right. As it was £60 worth of oil and I had spent a lot at the time, I decided to run it for the initial run-in period of my new engine. My RS4 box has covered 46k miles, so not that many. Syncros were crunching on every shift into 3rd and 4th unless I was really slow and deliberate with the change, and shifting in general was rough and poor. After a couple hundred miles I dropped it out and refilled with GL-4 and the problems all but vanished. I still get the odd crunch, i think i need to drain & refill again as Darren suggested to remove the remnants of the GL-5 from the box. I am tempted to try OEM oil next time.
GL-5 oil will show up worn syncros and wear out the ones that aren't in quick fashion.

[bertman]

ok,ideally what is the best thing to put in the box?

[Error404]

GL-4 is definitely better, I am starting to think the Audi engineers knew best with whatever they used from the factory.

[bertman]

Any specific gear oil spring to mind.I saw that you have used fuchs before

[Error404]

I am using Castrol Syntrans GL-4 at the moment.

[igor136]

I have the same problem. And Shell Oil GL-5. What is with this oil in diff? Can I leave it?

[BrianSmith_S2]

I have the same problem. And Shell Oil GL-5. What is with this oil in diff? Can I leave it?

rear diff oil is GL 5 SAE 90 according to workshop manual,

gearbox oil is G 052 911 A SAE 75w 90 and is GL 4

Just looked on opie oils and the castrol Syntrans Transaxle 75w90 is GL4+ and equivalent to VW spec G 052 911

[igor136]

Tnx

[Thuppu]

I did put Redline MT-90 GL4 oil in my box, but have to say it worked better before. It crunches on 2:nd and 3:rd on fast shifts. Propably my syncros arn't in the beast shape anymore, but I'm going to try some other oil. Maybe Midland Syncron..? Even that it's a GL4/GL5 oil, but it has been told to work really nice with these boxes.

[igor136]

Tomorrow I'll change the oil in the gearbox. Is good to leave Sintrax S6 75w- 90 GL 5 oil in the differential?