P. Swayzee

My car is at the dealer right now for what I thought was bad mounts. It would feel like the motor was rocking when hitting and releasing the gas pedal as if one of the mounts was bad. I got call today saying it was not bad mounts and there was play in my torsion bar. Would this cause the same thing I am feeling? Also when I take my foot of the clutch there is chatter like the pilot bearing is bad but they said it's fine. What else could cause this chatter?

P. Swayzee

So I got it back and the same thing is happening, the engine still feels like it's rocking but only when the trans is under load. I.E. I'm in third gear just cruising, I let off the gas and it rocks. Is this normal or is it the trans mount?

9krpmrx8

iTrader: (46)

Torsion bar on an RX-8? Powerplant frame?

alnielsen

iTrader: (4)

That's what I was thinking.

maskedferret

iTrader: (1)

Sway bars are torsion bars.

alnielsen

iTrader: (4)

Torsion Bars were used in place of springs on Chrysler products in the 60's and early 70's. I think someone has their terms wrong.

maskedferret

iTrader: (1)

Sway bars are effectively torsion springs connecting to the suspension on both sides of the car. It's not too far of a stretch, but yea; considering there is a suspension implementation called "torsion bars" as you point out, it is a bit confusing. Nonetheless, I would think they were trying to convey "sway bar", but I don't know if that fits in the diagnosis puzzle.

P. Swayzee

My receipt from Chapman says "sent to Mazda dealer, inspect engine mounts - ok. Check torsion bar and cross member - torque suspension. Found no problem"

The tech said that my mounts checked ok but my "torsion bars" were lose, they thought it was bent but when they compared it to the new one it was straight, they adjusted and tightened them back up.... That fixed the wheel hop but not the rocking of my motor.

From my understanding a torsion bar connects from the control arm to somewhere on the frame and stiffens the suspension under load.

Wingznut

iTrader: (1)

This is somewhat true. A torsion bar suspension uses torsion bars instead of springs. Like alnielsen mentioned, Chrysler used this type back in the day.

But alas, the RX-8 does not.

Arca_ex

iTrader: (10)

The shifter moves when you load and unload the engine, it's normal.

shadycrew31

iTrader: (6)

The chatter/whine most likely is the T/O bearing that **** always makes noise its just our car. The engine mounts are attached to the frame, the engine is attached to the trans, which is held in place by a powerplant frame (large 90# bar with sharp edges that connects the diff and the trans).

There are no other parts touching the engine that could or would be loose, causing the issues you describe. That said we do not have solid mounts so yes some movement is normal and to be expected. Most cars are setup like this.

P. Swayzee

The rock I'm feeling just seems too excessive and not normal. Only time I've felt this in any other car of mine is when the trans mount was bad. Do you guys feel a jerk when you left off the gas around 3k rpm in third gear?

dznutzuk

Transmission mount? We don't have a transmission mount. Our powerplant frame attaches to the transmission and also to the rear differential-so perhaps there's something going wrong there(diff mounts, ppf loose)? Theoretically if there is play rear of the transmission the engine could rock back and forth-just like if the engine is on it's engine mounts perfectly with no transmission attached it can easily rock back and forth.

Spin9k

This thread reminds leads me to the phrase "money for nuthin." I'd say you're being taken by whomever because you/they aren't familiar with the car it seems. Best bet is get under the car and see what is there and ponder the situation you describe and what you've been told.

Arca_ex

iTrader: (10)

The reason you've never felt this on any of your other cars is because it sounds like your other cars have all used cable shifters or shifter linkage. The RX8 shifter is like 10" long and is bolted DIRECTLY to the the transmission.

It moves. It's normal. Calm down. If you abruptly let off the gas in any gear it's going to jerk a little because you're reversing the load on the entire drivetrain, switching from the engine putting a load to the wheels to the wheels putting a load on the engine.

shadycrew31

iTrader: (6)

Don't listen to him, he shoots fire ***** out of his car... clearly he's doing something wrong.


/troll

Bladecutter

Lets see if I can describe this better for you:

When you are driving along, lets say in third gear, and you watch the shifter, get on the throttle hard for a while, and then release it, you can see the shifter move a bit from side to side?

If this is what you are seeing, then this is perfectly normal.
My 1 year old 2011 Sport has been doing this since day 1.

BC.

elysium19

iTrader: (1)

I think i had something similar after i had my engine replaced. they didnt align the powerplant frame properly, which has to be done anytime the engine or transmission is dropped. (Search on here for "powerplant frame" or "ppf"). The tell-tale symptom is a chattering sound coming from the transmission area when you let off the throttle with the car still in gear. But I think what you're describing is the same phenomenon, just to a mild extent. Did you have any engine/tranmission work done recently?

P. Swayzee

Since no parts have been used while they've had the car I didn't have to pay my deductible for my warranty, so far it's all been free.

P. Swayzee

My other cars had solid linkage that goes straight to the trans, but they were all front wheel drive.

I know when you let off there will be some type of jerk, but when it jerks will it rock 2-3 times, that's what seems abnormal to me. It was causing problems getting into gear at times where it would almost seem like it was going to kick back out. It only does that under fast acceleration.

P. Swayzee

I'm not watching the shifter, I can feel that move but it's very minimal and from my understanding normal. I'm letting off the throttle and the motor "rocks" back and forth 2-3 times. Doesn't have to be under hard acceleration. Go through a school zone, 2nd gear, 15-18 mph and let off the throttle, motor rocks a couple times. It's not a single jerk.

Spin9k

Suggest you take a vid of the problem...

Arca_ex

iTrader: (10)

Then post a video of you driving around if you're so adamant that your car is broken...

shadycrew31

iTrader: (6)

P. Swayzee

I'm just trying to give the best description via a forum. I don't think a video will help as you will not feel it, but if you're saying my motor is supposed to move then I guess it is right? I'm posting to get help, not to make your day miserable bro.

Now, there is a mount that connects the trans to the power plant frame correct? If this mount is bad wouldn't that cause the rocking under load?