Douglas Straughn

Hello, I have recently bought a 2007 rx 8 mt 6 speed,42k on the clock. Car is completely standard. When I bought the car the previous owner informed me that the ignition coils were faulty and needed to be replaced. Car has good service history and with the exception of the anti roll bar bushes on the left side being worn everything is perfect. I replaced the ignition coils and spark plugs and wires and had a mechanic clear the error code and that went well, car performed beautifully for a while. Recently I started having a strange noise coming from the gearbox area when the car is under light to moderate acceleration. Under heavy acceleration the noise seems to be drowned out. I have been to 3 different mechanics, 1st one said that it was the engine mounts but I highly doubt that because there is no noise while idleing or reving the car. 2nd mechanic said that it is the throwout bearing and pressure plate but I doubt that also because after doing some research of my own I learned that that bearing only makes noise when the clutch is depressed. 3rd mechanic said that it is definately the gearbox and I am more inclinded to believe this theory. We drained the gearbox oil and checked for filings but found nothing. Switched to a slightly higher weight oil and drove for afew days. Same problem. I have exhausted nearly every post on this and other websites for similar symptoms but have found none which match mine.
I have attached a video link so that you can hear how it sounds for yourself. If this is a repost of an old thread I am sorry, but I have tried looking everywhere. Any help will be greatly appreciated.
Thanks in advance,
Douglas S.

dannobre

iTrader: (3)

Kinda hard to tell from the video.....does it shift into and out of gears normally?

There is a lot of rollover gear noise in these transmissions......

Rebuilding them is very expensive for parts..so the best fix is usually getting a used low mile transmission and dropping it in

Douglas Straughn

Yes the gears shift very smoothly. No resistance at all

Douglas Straughn

I think the noise is quite audible in the video. You can clearly hear the hesitation as the rpms climb. Listen closely. Any insight would help. Im sure someone has heard a noise like this before.

beastman_5

This happens to alot of peoples Rx8's including mine, as far as I have read theres no damage where the noise is coming from

tpb7463

iTrader: (1)

You may hear it clearly, but the rest of us, not so much. Is there anyway to have something that isn't recorded off of another device?

It almost sounds like the engine is sputtering through the rev range. Is there any burning smell under the hood after you run it through the rev range?

EDIT: The Series 1 transmission synchros are sensitive to oil type/grade. I would highly advise you to stick to stock.

Douglas Straughn

Thanks for your replies, maybe its just clear to me because I know what I'm listening for. I would have to take another video, but it is exactly that, sputtering while accelerating. Almost sounds like slipping, and it only really bothers me when I've got the AC on and the radio off, when I put my foot down she does what she's supposed to. My mechanic who worked for Mazda for 13 years wants to take the gearbox out and have a look inside for any visible signs of wear. He assumes through his experience that it may be either the roller bearing or the gears themselves, but like I said in the original post, when we changed the trans fluid there was no sign of damage i.e pieces of metal or filings. For my wallets sake I'm hoping it's the roller bearing. For now I'll just be cruising until we figure out exactly what it is.
And no there is no burning smell under the hood after driving.
Thanks to you all for your help. Anyone else who has had a similar noise or any insight into this problem please write me. Any information will be appreciated and considered.
Thanks again.

dannobre

iTrader: (3)

Not sure why thye would think sputtering under acceleration would be a transmission issue....so a better video or more symptoms might help

There are some common RX-8 noises..."like marbles in a can" on acceleration that is a normal noise.

Usually if the transmission is going...you will get shifting or grinding problems

tpb7463

iTrader: (1)

Are you saying this only happens with the A/C on? Or am I misunderstanding?

Tell us the exact conditions this does / does not happen.

Douglas Straughn

Ok I will take another video today and try to post it later.
The symptoms are: sputtering/slight hesitation while accelerating gradually, while quicker acceleration either eliminates or muffles it. (Its hard to tell over the engine noise)
It happens every time I drive, hot or cold.
It happens with A/C on or off. Its just more noticeable with the windows up as you don't get the wind noise drowning it out.
The noise seems to be coming from the transmission area (underneath the cup holder in the centre console)
Hope this clears things up a bit. I'll try to get a better vid up asap.
Thanks.

ryden

I bought a 04 rx8 and the clutch grinds sometimes switching to 2nd and 3rd gear and makes a weirs sound when i put the clutch in but when I was cruising the highway and all the gears stopped working and the clutch sticks a bit but anyway it just quit while driving so did Iblow my engine? Or does the clutch need to be replaced? Please help