Hello all, Long time lurker first time poster. Ive had my Rx-8 (2008) since it was born so a little over 2 years now. I love the car and its treated me well. Previous cool car was a Mitsubishi Starion which was quite something, though is now in a million parts. Anyways, Ive had this issue for a while and was thinking about taking the car into the dealer to get it checked out (although I cant stand my dealer) and just wanted to check her before I brave the dealer. Whenever I turn right or left at a light or stop sign after driving the car for long distances (like on the freeway for 30 miles) I get quite abit of shuddering from the car. I want to say its from the back end (though i am not 100% sure). The car does not do this if I haven't gone on the freeway and have been on the streets the entire. My original thought was that the rear diff was low on fluids, but I took it in to a local lube shop and it was ok. Thanks in advance, Daniel

 

Shuddering through the steering wheel? or through the seat?
There have been power steering issues but you could just have tire or alignment issues.
Can you give a brief maintenance history?
Any good alignment shop could check this stuff out

 

Its a shuddering through the rear end. It feels like the car is caught in a puddle and is struggling to get traction (originally I thought it was because the wheels were slipping on the painted lines on the street). As for maintenance issues - Alls been good so far (knock on wood). Just regular oil changes and fluid top-ups.

 

My 07 6spd auto would do the shudder thing every time I would turn right and floor it. It even had new Kumho SPT's all around.

It's the traction control going off.

When I aligned wheels the rears were -2.1 camber on the left rear and -1.9 camber on the right rear.

The rear camber was evened to -1.9 on both wheels and the traction control is calm now.

 

had your tires changed recently?

 

if it only makes noises on turning it could also be the differential. Mine did something similar and it only happened when driving after a while as the fluid in the diff heated up.

edit: wow i need to read, missed that last line.

 

Thanks for the responses. I haven't had the tires changed (ever) but the tread life is still ok. The alignment should be ok, as the dealer re-aligned the wheels a couple of months ago, and even when the car was newly aligned (supposedly) the car still shuddered. I was thinking it was the differential, only because I recalled an issue on another car board (defunct now I think) where the diff fluid would heat up after the freeway and the gears needed for turning right or left were not lubed up, so slippage and shuddering occurred. Didn't think it would happen to a new car so fast though. If it is the Diff., is there anyway to conclusively prove it?

 

Thank you Jesus! I have had this issue since I purchased the car in april. Mine iis an 07 6spd with 27k and only does it after a good highway drive. gets worse after aggressive driving.(sounds like its going to break sometimes) been to the dealership three times and still is not resolved because I need the car nice and hot and then have them go for a test drive but every time i go they leave the car sitting for twenty to thirty minutes and then it wont do it. thought I was going nuts because no one on the forum knew what I was talking about. Please keep informed of your proggress.
thanks

 

I've got an 07 6spd auto, and just put on Hankook V12 Evo's with 36 psi @ 75 deg f (the max on this tire).

So I start to turn left with the pavement sloping down so I'm off camber when I turn left.

There's always a car coming so I hurry, but the tires are cold and stiff, and guess what?

Yeah, the rear brakes are pulsing one at a time to control to control tire slipping.

The lesson for me here is make sure the rear tires have good traction by the right air pressure, and for others to keep good tread on the back by rotating.

 

I thought the same thing when my 10 rx8 started having some diff issues with only 2000 miles on it. I could always prove it by driving around a bit just to get everything up to operational temps, and then get in a parkinglot or cul de sac, come to a complete stop, turn the wheel all the way one way, and start to accelerate slowly. I would hear the rubbing/moaning/stuttering coming from the rear tires and was able to reproduce for the dealer. They flushed the fluids and put a friction modifier in my diff and so far the issue hasn't come back. Not sure if it is really the same as the issue you are having, but I actually have a case number that was opened up with Mazda. Apparantly they have diff issues reported with a number of 09's and just a few 10's

edit: https://www.rx8club.com/rx-8-discussion-3/differential-noise-205533/

 

Guys I have similer issue with my car as well.
Basicaly does exactly the same thing as what all of you are discribing, but mine does it in any temp - cold or up to operating temp.

If I come to stop at intersection with any incline on it, then turn left ot right, rear of the car feels like I have detroit Locker in my diff. Steeper the incline, the worse it is.
None of these when car is going flat or going down hill(however minute it may be), and have no probrem going straight.

My car is 07 with Automatic, just over 13000miles on stock wheel and tire.

Should I change the differencial fluid?

 

Mity2,
I've got an 07 6sp Auto also, and I changed my differential oil with Mobil 1 syn gear oil 75w90 at 3500 miles. The magnet plug was really loaded with iron powder, but I've never had trouble or noise out of it. I had heard of some differential failures, and IMO that a good 75w90 syn is better than what comes in it.

I had just put my rear tires on last week, and while they were cold with 36 psi, I tried to accelerate while turning left, and pavement sloping to the right. The traction control went nuts pulsing the brakes on each rear tire a little at a time, and does it everytime I come out of the carwash.

When I'm on the track with everything warmed up, I can chirp my front tires at 96mph while braking for a corner, or corner at the limit, and if I do it right the traction control doesn't kick.

So yeah, you need to change diff oil now, and also at 30,000 miles or 30,000 miles from now.

Traction control can be ruled out by turning off after starting for about 7 seconds until caution light with swerving car comes on.

 

hey, fixed mine by changing the diff oil to redline.