I was test driving an 05 GT today and from Neutral to 1st, there seemed to be a thud from the tranny or diff. I don't know. Is that normal? Other gears were fine.

 

A bit of a thud or shudder is normal (at least mine does it)

 

everytime it shifts to 1st from N? this is a first time in all the manuals I've driven.

 

+1

 

Mine does it too.

 

mine does it as well. I'm chalking it up to 'quirks of the car'

 

Sounds like the clutch may not be completely disengaging or you are rushing the shift.

 

How would I be rushing to shift when it is from N at a standstill while waiting on the light? i'm gonna try another rx-8 to confirm.

 

I noticed that too. But it only happens once after I've come out of a high gear into neutral. It doesn't make the noise after I go 1st, N, 1st, N. I've also noticed sometimes while I'm driving it can be hard to go into first from N

 

Well, let's see. You're sitting at the light with the clutch engaged (i.e., pedal out), the light changes, you push in the clutch pedal and immediately drop it into gear. Crunch, thud (or insert your description of the sound of a spinning gear or two trying to mesh). Not saying you are doing that, I'm just posed that as a possibility for the source of the sound you are hearing.

FYI: The transmission mainshaft is turning when the clutch is engaged (i.e., pedal out) in neutral. (Listen for the sound of the shaft "rattling" against it's bearings in a quiet area.) So when you push in the clutch pedal (disengage the clutch) it takes a bit of time, like a second or less, for the main shaft to spin down. If you shift before that happens, you can get a crunch, thud or whatever you want to call it.

 

I hear you go48. It just felt strange. I know it happens to my other cars if I shift fast during autoX, which I attribute to differential shock (Subarus & miata), but never while putt-putting on the streets.
Will changing the tranny oil to synthetic help?

 

i think we all get the thud for first

 

Normal characteristic.

 

Can't hurt. Even if it doesn't get rid of the thud, shifting should be noticably smoother.

 

Mine does that before I even put it into 1st gear. Right as I begin to slide it into first gear it thuds. Been doing it for 35K miles and it hasn't got better or worse. So I figure it has to be normal. Also changed to Redline fluids 15k Miles ago and no difference.

 

I test drove another 05 gt yesterday. No thud whatsoever from idle/N to 1st. Hmm....