Ok I posted this in Under the Hood= No responses. Hopefully someone has some knowledge of gear installation.

I recently had 4.44 gears installed on my 01 S2000.
There is no gear noise to speak of (whine or grind)
Under medium and hard acceleration all is fine.
Whene cruising on highway in 5th or 6th under light
throttle, there is a vibration coming from the back end of
the car. I can make the vibration occur constantly with the
right mild pedal pressure, then if I take my foot off completely
or come out of gear the problem goes away.

Bad setup? Something out of balance? Help.

 

I have read both posts. Although knowedgeable about gears and their installation, I don't have a clue as to what might be causing this problem.

1. Where did you get the gears?
2. Where were the gears installed?
3. Can you vibration occur constantly with the right mild pedal pressure all of the time, at any speed?

Both 1/2 shafts and drive shaft are balanced. Installing them differently then before could cause this I would guess, but I would think that it would be constant and not just in 5/5 gear.

 

Ok,

I got the gears from another forum member and they are originally from J's Racing
I had them installed by another forum member with a fairly good reputation.
He said he put everything back together exactly as he took it off. We have since
changed the rear fluid at 800 miles or so and it was pretty murky looking.

I think the vibration is most noticeable in 4-6 with very, very light peddle pressure. You can basically feel the rear end going in and out of spinning with this very limited peddle pressure.

It is probably most noticeable in these gears because that is the only time I am using such little peddle pressure.

It is not constant. If I accelerate hard or medium, everything feels great. Its only when coasting that it is noticeable.