My wife was driving the Z yesterday and wanted to try the manual mode, she told me that when she downshifted in manu-matic mode to slow down it seemed to have a "thud" to it. So later that week I drove it and noticed the same thing, didn't happen every time and mostly occurred from 3-2 gear, and 2-1 if I do it, not if it does it by itself.

Has anyone else had this occur? Is it just because of coming down in rpms to fast and shifting at the wrong time? The tranny was just serviced less than 6k miles ago, and every thing was great.

 

Long shot here, but have you changed the trans fluid? If not, that might fix the problem.

 

How many miles are on the car and was it just a drain and refill of the transmission or a flush?

It is possible that they didn't fill it enough. Try checking the transmission dipstick.

Does anyone know if the transmission uses the same synchros for manumatic as it does for auto? Or maybe different sensors? It could be that if there are two different synchros/sensors.

Just my 2 cents.

 

Maybe you broke the transmission and need a new one.

 

dont go from 2 -> 1 anywhere greater than 5mph, you will feel the sudden thud/jerk.. 2nd gear is the lowest you should go, then it will AUTOMATIC shift to 1st gear upon the car coming to a complete stop. That how tiptronic tranny works.

Normal driving around 40-50mph... down shift to 3rd or 2nd to hear that beautiful engine

 

Did you buy the car new. When I traded my g35 in, I left the shift kit in the valve body and happened one day to bump into the guy who bougt it and I asked him how he liked it and he asked did I do sumtin to the tranny b/c its does shift hard in manual mode. If used possibly a shift kit in there

 

what year is the car and how many miles?

 

+1. This is what I thought. BTW. Nice pic in your sig. The Z looks fabulicious.

 

keep driving it and take it to a mechanic as soon as possible to get checked out

 

I had that happend to me after I installed my Transgo kit but soon to find out that i was missing about a quart of fluid in it!!

 

I would never use the tranny to slow down the car, that's what the brakes are for. I only feel that "thud" when down shifting at low speed. I felt it with the stock VB and after installing the Transgo kit the "thud" feels harder.

 

thanks man

it wont damage anything with engine braking.. plus it will save your brake and it will last longer.

 

mine does the same thing if i downshift above each gear max. speed. i think you have to be in the right speed to get smooth downshift. mine shifts smooth at these speeds 4-3 @35mph, 3-2@ around 18mph. if i miss 3-2 it will automatically downshift 3-1.

 

I noticed a little "thud" yesterday on mine when it would shift from 2nd to 3rd. Did it for about 10 miles and today it was normal? I'd check the fluid. If the problem doesnt go away and you are still under warranty, take it to the dealer.

 

I have an 04 auto & it does it. i have had the trans serviced too! I dont c there being a problem untel it wont shift anymore..

 

Engine braking is totally different than periodically downshift to slow the car down. But if you think it's OK keep doing it.

 

Hmmm.. cost to replace brakes vs engine....

 

Would a ground wire transmission kit or what not, help with this issue?

 

It can. I have the Stillen Kit and felt my shifts become smoother after I installed it a year or so ago. My radio volume increased a little bit too IIRC.

When I first got this car and was learning how to shift properly, I would occasionally get a thud or two when I shifted at the wrong point.

Then I finally got the hang of the 5 AT trans and started finding those sweet spots relative to where I was in the RPM range and what speed I happened to be travelling at the time.

Now my car doesn't thud at all no matter what speed I'm in or move I want to make.

Pay attention to how I'm shifting in this video I recently shot to show off my exhaust.

http://www.youtube.com/watch?v=Jz82VJ1t5pE

I have a feeling when I upgrade to the transgo with the same style of driving I'm displaying in the video I'll be fine and won't experience any thuds.

Have you guys with Transgo upgrades tried shifting like this? If so, report back what kind of shifts you're getting. Are they thud harsh like shifts, or smooth transitions into the next gear?

 

Ok so I just spent about 5 min typing out a long winded explanation on how a shift kit works and why you get a hard shift, and LOST IT, so here's a shorthand:

Shift kits make shifts quicker by upping the pressure in the Valvebody, and consequently use the clutchpacks less. Less clutchpack use='rougher' shift, but actually less damaging on the transmission (specifically to the clutchpacks) and more efficient.
So combine the fact that there is less clutchpack use (less comfort) and a noticeably quicker shift (like comparing granny shifting, for a lack of better words, to no lift power shifting) (yes I do realize that sounds extremely fast and fartious, but I can't make a better analogy) you get a rather 'scary' transmission experience.
I'd suggest searching this stuff up. and the stillen vb upgrade is pretty flippen mild, especially compared to the transgo shift kit (only other vb i know of), so you are GUARANTEED to have harder shifts.