Tuesday, October 15, 2013

Transmission oil

The Jetta has had a persistent transmission whine since I got it. When I checked it was a little low on oil. Interestingly this car wants a GL4 gear oil. This is strange to me as every other manual transmission I've ever owned from my '88 GMC to my '78 240D wanted ATF. It also seems that everybody has an opinion about what to use in there. Everything from G70 which is what VW provides and is water thin, to 75w90 synthetic gear oil. There are 2 different complaints, thin stuff like G70 makes the trans whine, heavy stuff like gear oil makes it hard to shift when cold.

With that all in mind I decided to do the "2 quart method", a quart of Redline MT-90 which is heavier and should handle the whine and a quart of Redline MTL which is lighter and should help cold shifts.

To drain the transmission that blasted underbody panel has to come out so the car has to be jacked up. Other than that its really no big deal with a big allen socket to get the plug out. Remember on a job like this to always remove the fill plug first, that way if something goes wrong you haven't drained out all the fluid with no way to put it back.

As you can see the stuff I got out is nasty, it smells vaugely of gear oil which it should but wasn't see through, very cloudy. Thinner than I'd expected too. I wonder if nobody had ever changed it and the gear whine was yet another reason the car was donated.

With the Redline in the transmission is much quieter. I'm well pleased with this and although the Redline (I got from Amazon) is fairly expensive at this point I feel its worth it. We'll see how the shifting is when it gets colder but for now its smooth, maybe smoother than before I started but I'll need to drive some more before I go that far.

Still got quite an oil leak going on. I can see where Keith changed the oil pan gasket an the leak now appears to be above that on the back side of the engine, maybe somewhere around the turbo. Its quite a challenging place to get at without a lift. Its possible that this car wasn't using synthetic oil before and maybe by changing to good synthetic oil some seals will swell and stop the leak. I'm not real confident but I'm willing to give it a shot. Otherwise I'll feed it and watch it close for awhile and then get it back to Keith for another shot.


Michael Sammartano said...

Found this thru tdiclub forums... What came of oil leak? 2000-'05's had cast aluminum oil pans which cracked fairly easily. I killed one, friend killed 2. Leak could also be result of bad seal on new pan.

Curt said...

I found out about the oil pan issue (they're also really low) from hitting the one on the 2005 Golf on a raised manhole cover, bent it but good.

The leak on my Jetta was a bad intermediate shaft seal. Keith replaced it for free since he'd put it in in the first place.