Tiptronic clunks if shifted to 1st while still moving

Hi folks, looking for a bit of help. I have a '99 C2 tiptronic. When I shift to 1st (in manual mode) when the car is stopped it shifts quietly, but if I do it while the car is still rolling (low speed) there is a loud clunk when it shifts. I'm guessing this isn't normal.

Quotes source post: 17994089

I think you have a ZF tiptronic, from an emerging era when German car makers thought auto trans could be sealed for the "life" of the car. But it's now 22-23 years old. I would suggest a review by a 996 specialist, or a german car transmission specialist of auto trans basics. The fluid, the bands, gears ECU etc. Pre synchomesh manual drivers let the car stop before engaging first. The 996 has good brakes, why engage first for no valid reason?

I also don't see the point in down shifting to first when moving.

My '03 does it as well...clunks when coasting, but if you shift while on the gas it shifts normally. I think I've seen thread on here where others have the same issue (or feature maybe haha).

The 02 and up 996.2 have a Mercedes 722.6 tiptronic. 996.1 has the ZF transmission (as stated above). You should start with a tranny fluid and filter change, and change the diff fluid. Find a German shop that knows the procedure and make sure you use the correct tranny fluid. As Bill stated above, there's no reason to manually shift into first when rolling. A low RPM shift will result in a clunk. Lots of automatics do that.

All Tiptronics start off in 2nd gear after warmed up. 1st gear isn't normally necessary unless you want extreme acceleration. I drive my Tip in Manual mode 100% of the time, but still start off in 2nd gear unless I need a "launch" take off.. Mine and everyone I have driven will clunk if shifted into 1st gear while coasting, I think the fluid pressure ramps up somewhat during this time and contributes to the clunk..If you are on the gas or completely stopped, no clunk...

Thanks everyone, rest assured I don't torture the car, I don't put it into 1st unless stopped, but was just wondering if the clunk was a "feature" (which it sounds like it is) or something I should be worried about.

Might want to check the Transmission Mount. They get clunky by breaking down over the years. A harsh 1-2 up shift under acceleration is also a key tell this may be the issue.

Quotes source post: 17995468

I totally agree with others, I wouldn't down shift to 1st gear when the car is still coasting. 2nd gear is plenty of torque. I wouldn't even dare do it in my manual cars. I only shift to 1st gear at a complete stop. The lower end torque is so strong in 1st, it makes for a super swift change to 2nd to avoid overrev. My tiptronic Porsche always starts off in 2 gear unless I override it.

Couple of things: 1. Check your transmission mount, bet you lunch it's shot. 2. I found that if I shift down to first while "slightly" accelerating it doesn't clunk. 3. Best not to shift to first unless you're stopped.