Changing the Tranny fluid for the 1st time since getting the A4 with Tip.
 

I bought my 1998 A4 1.8T with tip a little over a year ago and am wondering about my transmission. I know , I know.... tiptronic. :(

I'm not too sure what state my transmission fluid or my rear diff is in, since getting the car. (Nothing's wrong as far as I can tell, I haven't had any issues with my tip when shifting and all that, but I want to get some input on what to do, simply for peace of mind)

That being said, I've read from other threads that I should change the ATF every 45k, though the Bentley manual goes on to list 25k intervals for the 1998 1.8t A4s. :confused:

I imagine the best route is to change the transmission fluid, rear diff. fluid, and the filter. Then say about 1k later, completely change them again to get all the remaining bad stuff out. Then just have the transmission fluid, rear diff. fluid and filter changed every 25k like suggested by the Bentley manual.




My main question is if overall this is a wise/ the proper route to go?


1. Should I change both the transmission and rear diff. at the same intervals or does rear. diff last longer?
2. Is 25k intervals proper for the 1998 1.8T A4s?
3. Is changing all fluid and the filter then doing it again 1k later a good way to ensure there's no clogging and my ATF is ideal?

Thanks in advance!! :)

My advice is to start with the ATF change. You can change the differential gear oil in both diffs if you like; I've got a FWD A4 and have never changed the gear lube, only checked it once or twice in 10 years. It's at 257,000 miles now.

Get a filter/gasket kit, drain old ATF and carefully clean the pan and magnets. The new filter will install easier with a little Vaseline on the rubber seal. For ATF, use what you like; my preference is Valvoline MaxLife Dex/Merc, which is available in gallon jugs. Way less expensive than OEM or Pentosin German ATFs, and works at least as well in my opinion- I'm closing in on 100K with MaxLife. 45,000 mile changes are probably about right. You can just drain and refill without pulling the pan, but the pan design doesn't allow all the fluid to drain, so another pan pull is best. Make sure you do the filling correctly; car level, warm but not hot trans pan when finished filling (monitoring with VAG-COM is recommended) and don't replace the fill plug until fluid is dribbling out, and keep the engine running until the plug is back in.

You'll never get all the old ATF out, unless you removed the transmission and drained the torque converter. What you'll have is about 2/3 or so new fluid the first change, then closer to 90% by the second.

Thank you very much! I appreciate your detailed response! :) I would have been completely lost if no one replied. :(

I've tried twice to send some more suggestions about your ATF change, and both times AudiForums dumped the whole reply when I hit 'send', so this time I'll save it first!

Besides the ATF and filter/gasket kit, you'll need a 17mm hex driver to remove the check/fill plug, a set of Torx drivers (T27 and T20 in particular), four jack-stands, unless you have access to a shop's lift, and a tube of Silicone sealant, besides the usual stuff like drain pan.

Get the car up and fairly level on the stands. Drain the pan by removing the plug, which requires a hex driver (10mm?- not sure about that one). I prefer to leave the car overnight, without starting it, to maximise the amount of ATF that drains down from the clutches and torque converter. Use the 17mm to loosen the check/fill plug, and reinstall the drain plug. Remove the 27 pan screws with the T27 driver- a cordless reversible drill speeds things up here. Lower the pan carefully, because there will be ATF in it that didn't drain out. Next you can remove the filter, two T20 socket screws, then install your new filter by pushing it up. The ring-rubber gasket is alway pretty tight, so use some Vaseline on it, otherwise it can be a challange.

Clean the pan inside and out, also the magnets which will be found in it. Apply a film of sealant to the pan's flange, stick the gasket in place, then another film of sealant on the upper surface of the gasket. Wipe the transmission's sealing surface clean, then install the pan. When snugging the screws, I skip every other one so it takes two passes around the pan to get all tight, but don't twist harder than it takes to ensure they stay put.

At this point, you are ready to refill and finish the job. I'll track down a few pictures of the cheap setup I use to refill; essentially it is a funnel on a ladder, a length of 1/2" ID vinyl hose, and a 1/2" copper elbow on the end of the hose that fills the transmission. Lastly, I use a needle-nose channel-lock plier to pinch off the hose when the trans is full of ATF and overflowing into the drip pan underneath. When it does that, after shifting between Reverse-Neutral-Drive a few times (always apply the brakes to stop the revolving wheels before the shift) take the hose out and put the check/fill plug back in. Then shut the engine off, take it off the stands, and go for a drive.