Just Replaced Gearbox & Diff Oil

[AAH!]

I have just changed my gearbox and diff oil and have used FUCHS SILKOLENE SILKTRAN SYN-5 in both, as recommended by oilman at opie oil.

http://www.opieoils.co.uk/performance_lubricants/pdf/silkolene/SILKTRAN%20SYN-5%20-%204%20Wheel.pdf

The rear diff was easy, no stuck plugs, although the replacement plugs I got needed some stupid specialist audi tool to fit them which we didn't have, so I reused the old ones. Filling was easy as the rear diff is filled level (1.3 litres) with the filler hole.

My RS2 has the CRB gearbox which requires 2.3 litres of gearbox oil filled to 16mm below the bottom edge of the filler hole. (S2's and early RS2's(?) with the CGR gearbox takes 2.7 litres and is filled to 7mm below the bottom edge of the filler hole).

Again no stuck plugs and the replacements plugs where normal and usable. However I couldn't seem to get more than about 2 litres of oil in without the level getting too high. Might some of the old oil have not fully drained?

When draining the oil from the gear box we just undid the drain plug from the bottom of the gearbox housing "A" in the pic below, should we have also undone the drain plug marked "B" to fully drain the gearbox?


Angus

[iain1067]

Possibly, did you drain it hot??? I have done a few box oil changes myself, it seems to vary the amount you can get in, just check it in a few days time.

Iain

[Greg_S]

it would make sense to do it hot since that is what you would do with engine oil

[AAH!]

Possibly, did you drain it hot???

it would make sense to do it hot

It makes absolute sense to drain it hot.... but I didn't. I will check the levels in a few days.

I was amused that the Audi workshop manual says "Check oil level with a suitable tool (such as a length of wire bent to shape)" It's not very German/Audi not have a a specific tool for this job. I used a wide cable tie bent at right angles to check the level, much more effecient than the wire method as you can actually see the oil on the cable tie.

[Fat Audi 80]

Any noticeable difference in the way the car drives?

Cheers,

Steve

[PeteRR]

When draining the oil from the gear box we just undid the drain plug from the bottom of the gearbox housing "A" in the pic below, should we have also undone the drain plug marked "B" to fully drain the gearbox?

Ideally yes. A small amount of oil is held back if that plug is not also removed when draining the oil, as you found.
I'm sure you could just leave it if the oil you drained was pretty clean, or if you don't mind the expense give it a couple of hundred miles and fully drain it again.

[AAH!]

Any noticeable difference in the way the car drives?

To tell the truth the gear changes actually feel slightly more notchy than before in first and second, but I think it is because I am paying close attention to it for a change and in reality it is probably the same. Having said that once in gear it does feel very smooth (maybe even smoother than before) when on the move.

@PeteRR - thanks, now I know for next time.

[volcano rs]

i have couple of bottles of ep 90 gear oil can i use this in my gearbox and diff or not ? thats all the grade numbers that are on the containers .

[pixsaudisex2]

ep 90

ep 90 means extreme pressure oil 90 thickness this stuff is used in axles and diffs put it in your gearbox and it wont last long at all takes to long to thin down and it wont make it up all the oil ways dont get me wrong some gearboxes use this stuff but audi gearboxes 99.9 % of the time need atf oil auto trans fluid its nice and runny and red thats what should go in most gearboxes all though if you have an lsd rear diff you will need lsd oil or it will not work its like treacle but always do your best to put in what comes out after a few years of doing it you can start to tell what comes out by smell and vision..

[volcano rs]

thanks for the info mate i'll scrap that idea

[PeteRR]

ep 90 means extreme pressure oil 90 thickness this stuff is used in axles and diffs put it in your gearbox and it wont last long at all takes to long to thin down and it wont make it up all the oil ways dont get me wrong some gearboxes use this stuff but audi gearboxes 99.9 % of the time need atf oil auto trans fluid its nice and runny and red thats what should go in most gearboxes all though if you have an lsd rear diff you will need lsd oil or it will not work its like treacle but always do your best to put in what comes out after a few years of doing it you can start to tell what comes out by smell and vision..

Right about EP90 for the rear diff, but there's no way you want to use ATF in these gearboxes! (ATF 'aint much good in any manual gearbox really, due to less than ideal lubrication properties).

If your manual states SAE 80 or similar, a decent 75W-90 GL4 synthetic gear oil in the front diff/box is good.
(I used Red-Line MT90, or there is Castrol TAF-X, Silktran Syn-5 like Angus used etc.)

[pixsaudisex2]

erm yeh you are right but had to much beer last night an im pretty ill feeling right now spent over 6 years doing gearbox repairs as well..

[PeteRR]

Ooops!

[volcano rs]

i only need to top up as it might be a bit low so what oil do the s2 5 speed use as standard ? can i use the ep90 to top up the diff ?.soon the gearbox will be replaced with a 6 speed one then i'll use the best available thanks for any help