Nemick

Hi all,

I think I have the beginnings of a potential AT problem and I would much appreciate some advice and input from you. My car is a 2001 Audi A4 with the Tiptronic transmission. I have no idea of the transmission number or type, so bear with me.

I have two issues, one of which is intermittent. I'll try to describe them both.

1. When in normal "automatic" mode, the car drives fine and changes gear correctly with only one concern. As the car shifts into 3rd gear, it feels as though something is slipping for a second or two and then all is normal. As an example, lets say the car shifts from 2nd to 3rd at 3000 rpm. The revs drop from 3000 to about 2300, maintains 2300 for one or two seconds and then drops to 2100 and then drives normally. I have not detected this in any other gear, but it is bothersome.
When using the steering wheel buttons in Tip mode, this does not seem to happen. Any thoughts?

2. Occasionally, after using the car in Tip mode and coming to a halt, the gear selector will not go into park. It feels as though it is fouling on something, somewhere. After a few tries, it will eventually go into park and act normally. As i said, this does not happen all the time, but I'm concerned that something may be on the way out and i would like to catch it before it does.

Just to be clear, I am completely clueless about automatic transmissions, so I don't know where to start with this. No codes have been thrown, at all. It is also worth noting that I had the GIAC Tiptronic chip installed at the same time I did my engine chip. I don't know if this might be relevant.

Sorry for the long post, but I don't know how else to describe this.

4Driver4

I would argue that at Tip trans *is* a problem.

Any codes? Have you checked the fluid level? How many miles on the car? When was the last time the trans fluid and filter were changed?

footyboyack

Firstly, as to the RPM drop you're seeing in third gear, this is the torque converter locking up (at least partially). I'm not sure if this is something to really worry about, depending on how many miles the trans has; the lockup on our cars, especially in third gear, just isn't that seamless. You may also be experiencing a slow lockup due to lockup clutch wear in the converter, lack of ATF pressure to the lockup piston, or due to an aging/slowing TC lockup solenoid (those things operate at 10k hertz and have a duty-cycle; they apply gradually, not like an on/off switch). Fyi, the TC has at least a partial lockup in gears 3,4, and 5 on our trans.

As to why you don't experience this event in Tip mode: To the best of my knowledge, the TC locks up much less, maybe not at all, when driving tiptronic due to the fact that it is a "sport" setting. I assume it has to do with preventing increased stressed on the lockup clutch and maybe quickening shifts a bit.

As to the gear selector issue... Hard to say. It would be either an improper shift cable calibration, a faulty multi-position(name? multifunction?) switch, or maybe even a faulty Transaxle/transmission control module. Might want to try some contact cleaner on the leads going to and from the TCM and the "multi-something-or-other" switch if you don't suspect it to be a mechanical problem with the shift lever/cable.

P.S. IF your TCM throws a code along the lines of "torque converter lock-up stuck off" or "torque converter lock-up speed deviation" - I think it's a P0741 diagnostic trouble code - then suspect a faulty seal within the converter. This will require buying/installing a rebuilt TC.

P.P.S. One good way to sharpen up your transmission shifts+lockups would be to simply drain/refill the fluid, depending on when it was last done. Make sure you know what you're doing or if you'd be having a mechanic do it, that he knows what he's doing. It's a detailed procedure. Also take close notes on the condition of the fluid as it comes out, and inspect the contents of the pan and pan magnets, and make analysis based on what you find. The stuff coming out is the very best way to diagnose the health of your trans.

Hope this helps.

Nemick

Thanks for the responses. The car and tranny have 146,00 miles, so far. I changed the transmission fluid about 4000 miles ago and followed the instructions to the letter and used VagCom too. No codes at any time and the old oil looked good, ie. no shiney bits. I swapped out the filter too and tore it apart to look for any debris. Everything was clean and nothing on the magnets. Maybe I'm just being paranoid, lol.

4Driver4

I'd recheck the level.
Did you check codes recently?

Nemick

I haven't checked codes since the refill, but I shall.