I searched on this and couldnt find something related.

Whenever I am in a low RPM launch situation, the rear end shudders like the wheels are hopping (obviously they aren't).

This is especially exacerbated when the front wheels are turned, like having just backed out of a parking spot.

If i had to guess, I would say either a bad rear diff, or possibly some bad diff bushings.

Any one of the suspension experts have any insight here? I could always take it to PFS, but that would take the fun out of it

Steve

 

are you sure your tires arent spining?? i launch at around 3k rpms and mine do(seq).

if anything, it sounds to me that your shocks or struts are going bad. there moving freely and not making proper contact with the road. if that is the problem you could be putting yourself in alot of dangerous situations.

 

sounds like normal behavior from the LSD. when making tight turns like a U-turn or parking spot, one wheel has to slip. Could be the clutch packs or whatever. Mine does it if I'm making a U-turn. But it definately shouldn't do it in a straight line.

 

This happens when the diff fluid is getting old. It's thought to be the disk sticking which is made worse when the car is cold or when you're turning. Replace the fluid with a high quality fluid. I recommend the Idemitsu 75w90 racing gear oil. Let me know how it works out.

http://www.mazdatrix.com/q-supply.htm

 

i just bought the car and the paperwork says KD Rotary changed the fluid about a year ago. The previous owner only put 3k on the car in the 3 years he owned it, so its likely not the fluid (unless the diff is just bad).

 

The FD uses a Torsen LSD - torque biasing done by friction between worm gears. There should be no chattering like is often present with "clutch-pack" LSD's.

However, the wrong friction characteristics of the fluid could still cause "stick/slip," which is what you were talking about. However, I'd be more inclined to (as others have said) look for a PPF or bushing issue.

Dave

 

Thanks Dave. I can always take it back to KD Rotary or hand the keys to Ray at PFS for a day or so.

Someone just needs to tell me what it is b/c I want to turn the wrenches

 

Mine did the same thing. Turned out to be a bad motor mount. Does your gearshift lever move/shake at the same time?
-Spence

 

Congrats on finding a replacement Steve. I hope it is as nice as the first one

 

Adam -

I couldnt have done it w/o you. Your guidance through the whole process was fantastic. As a result, I am a proud owner of a CYM w/ 49k on the clock.

Steve

 

I had a 1st gen that did this...it turned out to be the clutch.

 

Glad to be of assistance . Congrats!!!

 

Motor mounts and Diff bushings did it for me.

 

thanks guys. Ask 10 people and get 10 answers

It only seems to occur at 1500 rpm or less. That help?