So about 2 months ago, I noticed that my gears were starting to grind in high rpm above 5,000 from 3rd to 4th. I continued driving as normal, I remember my previous car the Mazda 3 did this when I first bought it and the car ran well for 2 years until I got rid of it. Anyways when I purchased the RX-8 I knew about some of the problems that could happen to my car and purchased a warranty from my Credit Union for peace of mind, it was from Route 66 Warranty, the deluxe coverage. Anyways I figured I'll take it to the dealership and they'll be able to fix it, I had a feeling it was the synchros. Plus I'd get a loaner car in the meantime; enjoy the gas mileage.

Well about a week ago I take it and then they call up and tell me that my warranty doesn't cover the synchros and that 2nd, 3rd, & 4th gear need changing. He told me to call Route 66 and just "bitch" at them and that maybe they'll be able to do it that in some cases they'll go ahead and do it. Well I called and they said no because it's a soft part and the total to fix it would be $2,100 roughly. They'd have to replace the transmission.

This isn't exactly news I wanted to hear and with work and school up my neck, I don't really have that kind of money to spend to fix my car, let alone the money I dump for regular maintenance and about $50 in gas a week...I've been reading over the past few days and apparently their is a transmission fluid? That is called BG SynchroShift II? That shifting the gears makes it smooth and no grinding all the way to 9,000 rpm. I know this won't heal my worn synchros but it'll extend the life of my transmission and will definitely save me some money? The guy from Route 66 also told me I could take my car to any shop and that they'll just have to call them and they'll arrange to fix it. Perhaps find a place that can fix it for cheaper? Cause James was the person I spoke too for Route 66 and he said he'll be able to help me financially a bit with the cost, to just get back at him in a few days.

Pretty much I just want the grinding to go away, I'd like to fix the issue, but if replacing the whole transmission is what I have to do, then I rather find some fluid that will temporarily prolong the life of my transmission until I can save up some money to fix it down the road.

 

Hello and welcome to the club..

Look there is never a 'mechanic in a bottle, tin, jar or jug'...all you will be doing is short term masking of any issues you may have, and I use the term 'masking' very lightly.

Yes, changing the Trans fluid (oil) could help a lot, IMO all Trans and Diff fluids should be renewed at least in half the time the manufacturer recommends, I say half the distance, or change these fluids once every 3 engine services....instead of one in 6.

Just interested, how many miles has your 8 done?.?..

As for your Transmission again, get the fluid changed and see how it does...

In the long term, you can purchase a BRAND New Mazda RX-8 6 Speed MT used in a Series 2 RX-8 which is a much, much better trans for about $2300 USD, plus you need a New Shifter and a small Shifter Bush as it does not come with new Trans Assembly, and the Reverse shift pattern for Gear **** and actually Reverse Gear Selection/Changing is different...a new Shifter **** from Mazda costs$$$$$'s....you can use your old one.

Here are the new Part Numbers for the Mazda Transmission (While Stocks and Price Lasts).
Remember fitting is extra as is shipping of said parts..

P6Y1-03-000 Trans 6MT $2350.00
P610-17-510D Shifter $180.00
P611-17-492 Bush Shifter $6.90
3 x 9945-00-612 Bolts (3) $1.65 Each

So I guess it all depends on how much you like and or want to spend on your RX-8, personally IF you can afford it (or save up) there is only one way to go, and that is a all new Series 2 Trans.

So many times I (we) see so called repairs and fixes which later gives issues with more cost and money and down time....down the drain.

 

Thanks for the quick reply friend! I forgot to mention the mileage. It's a 2005 with 53,500 roughly on the body. The engine block, engine itself was just replaced about 3,000 miles ago back in December, under warranty. So if I were to replace it, best just buy it myself and have a mechanic install it?

 

Yep, there are a few ways to go about this...

And you can do the footwork/finger work on phone...

Either contact Paul @ Mazmart (one of our forum vendors) he gives great service, give him the Part Numbers and see what he can do price wise....so you can buy all the above parts yourself and then get them installed (don't forget to look at your CLUTCH, that is another $600 (roughly) in parts (depends where you go), but well worth changing IF you are removing your Transmission.

ALSO, think about this one, YOU MAY want to go down the road of having a Mazda Dealer supply and even fit, tell the dealer you have had a parts quote (or their Parts manager) and then get a price to supply install or just install, you supply, that way you are protected under Mazda 12 months Parts Warranty.

I am certain Paul will give you advice on who can or might do the job cheaper away from a Mazda Dealer....either way ask about a/the Warranty, I think in the USA Mazda will still warrant the parts for 6 months If not installed by a Mazda Dealer??...I am not sure there on that one though.

 

I'll keep that in mind, but aside from the transmission replacement; since the prices are scaring me. What would be the best transmission fluid to put into my RX-8 to prolong the life of the transmission with the grinding? The one I posted the BG SynchroShift seems to only work on EVO's...

 

Use a GL4 Trans Oil, like Redline MT90, some a Motorcraft (Ford product), there are many threads here on transmission oils...good luck.

 

Red Line Synthetic Max Gear Transmission Oil MT 90 GL 4 75W90 2 Quart 50304 | eBay

This right here will work for my RX-8? How many quarts would I need initially? And how often should I add some to my car?

 

The transmisison holds 2 quarts. You will not need to add any more until you later drain it for the next change, OR if you find a leak. Our cars don't burn transmission fluid

But, why are you getting it from ebay? It's just as cheap from reputable vendors. Ebay has a risk element that I wouldn't play with on fluids.

 

I was going to purchase it from eBay, but after your comment I may not...lol Could I drain it myself and add these 2 quarts then? Also my buddy says that my RX-8 doesn't use transmission fluid, it uses clutch fluid? All I'm really looking for is fluid for my car to prolong the life of the synchros cause it grinds from 3rd to 4th in high rpm

 

Your buddy is wrong.

Our clutch system uses brake fluid, our transmission uses GL-4 transmission fluid, also known as gear oil.

Transmission fluid replacement for the series 1 RX-8 is a cake walk. Pull the drain plug, drain the fluid into a pan. Then re-install the drain plug. In the car, remove the shifter (shift ****, console trim, allt he way down to the shifter itself. Pull it out of the transmission. Pour the entire 2 quarts into the transmission through the shifter hole. The spec fluid level is 2 quarts exactly, so you can't overfill it this way unless you stopped the drain before it was finished.

No messing around with fluid pumps.

MT-90 is the most popular fluid. A few other fluids are also loved, and I admit that they ARE probably better, but they are usually harder to obtain, meaning more in shipping costs. MT-90 is an easy go-to choice due to it's price and availability, and it's proven.

Keep in mind that fluid will help, but failing motor mounts might be another cause for grinding gears when trying to shift. Same with needing to bleed the clutch hydraulic line.

 

Thank you! So MT-90 is what I posted linked through eBay correct? I'll go ahead and purchase that then. Also my motor mounts are worn out, they have been ever since back in December when I had my new engine put in. But the guys at the dealership said it was my synchros from 2nd-4th gear that needed changing? And what do you mean by "needing to bleed the clutch hydraulic line"?

 

or buy a good used transmission and just have it swapped out.

 

Thank you so much for this thread. You pretty much described the problem I have been having.