I just recently bought a 2004 rx-8 and three days after driving it the AT light came on and the traction control light also came on simultaneously. I brought it to the shop and my trans range receptor had a short. They put a new one in the transmission and it also shorted out and now they are currently looking for what is making the receptor short out. They told me it was most likely the computer for the transmission. I was just curious if anyone else has had this problem?

 

Where did you bring your car?

 

This is my first time hearing a TCM going bad. I had my AT light come on at frist the scan tool said a bad solenoid. They reaplced the solenoid and the light still came on. So they opened the transmission to find out it was burnt.

 

Charles i think you posted on the worng thread

 

^+1 i would bring it to a better shop or a transmisison shop

 

Never knew the MAF could cause an AT light. Learn something new everyday

 

The place I brought my car to is a transmission shop called transmission technicians.

 

Also when both the AT and the traction light comes on the car becomes extremely slow to accelerate. It feels like it gets stuck in a higher gear or goes into fail safe mode. Could this also be caused by the MAF?

 

No I haven't installed any aftermarket intakes, the car is stock.

 

Im having a simalier problem with my 06 shinka auto. My car's trans light is on and and it wont shift right and is like tacking out at 5g's. It wont rev or shift right. Im taking it to be put on a code machine today. Just wondering if any knows off hand what i am looking at. Thanks

 

How many miles are on it and what kind of work has been done to it?

 

Hello Rx8 club,

I am an original owner of a 2005 mazda rx8 AT with ~35k miles. Occasionally during acceleration the car will jerk forward when it shifts from 2nd to 3rd gear. Recently, there was a clanging sound that happened when the transmission was downshifted (3rd to 2nd) as I came to a stop at a traffic light. There are no sensors or warning lights that come on. The mazda dealership just inspected the car in November and they didn't say there was an issue with the transmission.

Is this just an indication that I need to have the transmission fluid changed? It hasn't been done yet but I realize its about time. Any feedback you guys can give would be appreciated.

 

Check the fluid level first, but now would be a good time to have the transmission flushed.

 

My "AT" warning light is on with my daughter's 2005 Shinka, and when I took it to Autozone they tell me the error code is: PO743
They said it was the "Torque Converter Curcuit Solenoid Valve Circuit Malfunction." Can someone tell me what this means?

 

My wife has a 2004 RX8 with the AT and a brand new engine. (car now has 75k miles on it, and the engine only has 10k miles on it.)

After the new engine, we started having the AT light come on sometimes. And somewhat rarely, the AT would get stuck in a gear. (often first or 2nd.) Typically it would self-correct after the engine being turned off.

And on multiple times I left it with my Mazda Mechanic, they couldn't duplicate the problem. Based on the codes, they would replace the solenoid involved, but that wouldn't solve the problem. (and the problem mostly happened when my wife drove the car, and not me.) And I was really close to just buying a new computer control unit for the transmission.

But then, when I was driving it on the freeway, going down hill, I shifted into 4 gear, (because I usually drive it in manual mode, with the paddle shifters,) the car beeped, the AT light came on, and the care decided on it's own to quickly shift from 4th gear, down through the gears, down to 1st gear. While we were going 60+ MPH!! Of course the back wheels locked up and we skidded down the freeway a few hundred feet. I barely kept us from not spinning or going off the freeway. Thankfully no traffic right close to us, so no car accident.

But drove back home with the car stuck in 2nd gear. Always fun driving 50pmh in 2nd gear LOL.

This time when I told my mechanic to find the problem, no matter how long it took, he was able to detect an intermittent problem in the 'Range Switch'. So the Solenoid was not the root of the problem but just the first theory. I guess when the 'Range Switch' goes bad, then the automatic computer gets bad information, and therefore makes bad decisions. (or doesn't let you shift, regardless of which mode you are in.)

After the range switch was replaced, it's never had that problem again. But it does still shift 'roughly' sometimes. Especially when the tranny is all warmed up. Sometimes it shifts quickly and like butter. And then sometimes it takes three or four seconds to shift. And it's rather 'clunky' shifting into reverse lately.

So I'm going to get the transmission fluid checked (again.) It has to have the cleanest (used) tranny in the world because the fluid was changed like 4 times in the last year. But I just have to be sure it's still good.

Elsewhere on this forum, it is claimed that GL4 type of fluid is way better for the tranny than is GL5 fluid, so I'm going to check on what type my mechanic was using when he was filling it previously.

I might just end up putting in a new 'brain' computer for the tranny, or some other 'upgrade', after consulting with my mechanic. But I really want this tranny to be smooth!!!! Arghhh.

Any other advice would be appreciated. But hopefully my experience helps other owners out there.

 

The computer modules can be expensive, I suggest you discuss with your mechanic what happens if that doesn't fix the problem. I don't think it has anything to do with the current problems.

Sorry, not too familiar with automatics to help more. Clunky or slow shifting can be a problem with the trans itself (especially if it has a history of rough shifts like you describe). The clutch packs wear out from that kind of abuse. ATF fluid isn't the same as GL4/GL5 manual trans fluids, it's a whole other game.

 

I will talk with my mechanic about the clutch plates thing. Maybe he can diagnose the issue from his 20 years of Mazda experience. But he's so popular that his calendar was booked out two weeks. Lol

 

I've been having the same problem with an automatic '04 Rx-8 I bought in December. It randomly jumps in 1st gear while I'm driving it. I shut it off for 20minutes, turn it back on, and it rides smoothly afterwards for the most part. Put a new CPU in & the problem still wasn't corrected. Is a new range switch the best solution for that problem?

 

Hi Windham, I figure I'll post my reply on this thread also:

"On my wife's RX-8, the first problem (of shifting to the wrong gear at the wrong time, or getting stuck in one gear) was due to the 'Range Finder' switch thing. Once we got that replaced, we never had that problem again. I think in an Automatic Tranny, the 'Range Finder' piece is the 'sensor' that figures out how fast the wheels are moving relative to the speed of the engine, and that information then goes to the little computer that controls the Automatic Transmission so it can decide what gear it should be in. If that goes bad, then the control module (or computer brain) makes bad decisions, which can result in it either being very confused to the point of making no decision (it gets stuck in one gear, and no manual input makes any difference) or it can make a bad decision, and it will decide to shift down to 1st gear, even though you are going 70 mph, and you were in manual mode and told it to go to 4th gear.
(yes, that happened once, scared the living $hit out of me. Which is why I force the mechanic to find the root cause not matter how long it took.)

After the Range finder was replaced, all was good until it started to shift slowly, especially when it was hot. it would struggle to shift from 1st to 2nd especially. (or anytime a lot of torque was involved.) In that case, it was the clutch plates eating themselves into shavings. The tranny got stuck in neutral before I could even drive it all the way to the shop. [metal shavings had clogged up the tranny fluid filter, even though it had completely new fluid just weeks before that. So I had to do a complete rebuild on the transmission after that. [as a bonus, I ended up with a new aftermarket Tranny fluid radiator which probably gives me 30% better cooling power, but engine can still get a little bit above 'normal' temps on long uphill climbs. Nothing too serious however.]
So $5000 later, it drives like a dream now. I only have 90k miles on it. But now that I have a new engine, and a new Transmission, I think I can get another 100K out of it, because I am going to take good care of it, and drive it correctly. [I think the previous owner(s) had no idea how to take care of an RX-8. It is nothing like a normal car. I even run Royal Purple 2-Cycle oil in it. Sure, the engine re-manufacture people wouldn't support that idea, but after a bunch of research, I'm convinced that quality synthetic 2-cycle oil is the cleanest burning, most protective oil that money can buy. ]

Anyway, that has been my experience thus far. Hope that helps. Personally, I just think an automatic tranny should never have been paired with a Rotary engine. Just like a motorcycle with high-rev engine, they should have stuck with only manual transmissions. But you know the marketing people at car companies, they don't listen to the engineers.... LoL."

 

I'm terrified at the sentence about you running 2-cycle oil in it. I hope you mean in the fuel, not in the oil pan.

Engine temps have nothing to do with transmission cooling, so might want to get those overheats looked into. The temperature needle should never move.

 

I'm so glad I have the 6 speed auto 07 RX8.

They did replace trans at 22k miles, but now it runs like a dream, and I was able to cool it even 14 deg f more with a tube and fin ATF cooler.

This is a more modern Aisin which goes into many different cars and Toyotas.

I've tracked car before and after new trans, and it's a smart shifter that holds gear if you get out of gas for a few seconds, so you can pick up in same gear after apex.

 

Thank you for your concern about my car and engine. Agreed, engine temps have very little to do with transmission cooling. (other than when your factory radiator is a 'combo' radiator that cools both the tranny and the engine in the same assembly, even if one is on top of the other, they are connected.) So when a separate tranny radiator does that cooling, it is mechanically separate from the engine cooling radiator. Does that make a big difference in tranny cooling? probably. Have a big affect on engine cooling? probably not. ;-)

As for oil, the theory is that 2-cycle oil is typically 'thinner' than conventional 4-cycle oil, and indeed you can't buy it in different 'weights' like you can with 4-cycle oil. So I probably wouldn't recommend it for anyone driving around in temps over 90 degrees F. Or driving long distances up steep mountains. Especially the mineral (dino) version of 2-cycle oil. Theoretically it could break down under high heat and give less protection. But only theoretically.** [if you have info on the inferior performance of 2-cycle oil in general, please share it.] But I think the synth stuff I'm buying has plenty of 'Friction Modifiers' in it (additives) to keep engine wear to a minimum for longer than the tranny will survive.... LoL.

In reality, based on my research, a synthetic oil is much tougher under high heat than dino oil. (or more properly retains it's lubricity.) Also my wife drives this car rather infrequently, and only for short distances. So the engine is usually barely even getting up to 'normal' temps before being turned off. And we live in the North West, when typical outside temps vary rather little. Mostly from 30 degrees F to 80 degrees F all year round. So the oil being 'light weight' is not an issue for me.

However, carbon deposits and other gunk from burning the oil (as in a 2-cycle engine) is a HUGE issue for my car, since my wife drives in Auto mode most of the time, and the dump thing is programmed to run at about 2000 RPM most all the time, unless you massively stomp on the gas.

So 99% of the time I do not have a 'heat problem'. It has run cold to perfect mid-temp for almost 5 years in 99% of our driving situations.

I only noticed the 'high heat' issue (meaning slightly above normal temps) one time when driving up a long mountain road on the freeway at 70 mph in 3rd gear at 6000 rpm in 90 degree weather. (with the air-conditioner on.) And as soon as the load dropped at the top of the pass, the temp dropped to normal in like 30 seconds. So I'm not worried. If I only do that sort of driving once every 3 years, I think I'll be O.K.

-Tim G

** as to the chemistry of 2-cycle, I love that it is super low 'ash' which protects fouling of my injectors, and spark plugs. And 2-cycle oils tend to use additives that are designed to coat the injection chamber with protective molecules while being burned. And not use additives that don' burn well (such as metallic based chemicals.) So based on my research, I trust my engine to Royal Purple 2-cycle Oil instead of the 'mfg recommended' stuff. It is 3 or 4 times more expensive for a reason. It has to do more to protect the engine, while being injected. Which is exactly what I want on those APEX seals.
One thing I know is that on my RX-8, the first engine had 'standard' oil in it for the first 76k miles, and the Apex seals failed catastrophically. So on my new engine I'm doing something different. But only the next 50k miles will prove whether I'm crazy, or a genius.... LoL. In 20 years, I'll let you know. ;-)

One source:

"2-stroke oil uses a different additive package that is designed to not leave excessive residue behind when it burns. This is because 2-stroke engines burn oil by design, whereas automobiles keep the oil more or less separate from the combustion. 2-stroke oil is either "ashless" or "low ash" which means the detergents and anti-wear compounds will burn off either completely or almost completely. Automotive oil may use additives that do not burn such as metallic compounds." -Ryan Carlyle, BSChE, engineer at an oil company.

https://www.quora.com/What-is-the-di...-cycle-engines

https://en.wikipedia.org/wiki/Two-stroke_oil

https://www.hunker.com/13404451/diff...nd-2-cycle-oil

 

tganstrom,

Throw away any ideas you have about your auto and listen!

If your auto has an internal cooler in water radiator which I'm sure it has, the temps of trans AFFECTS temp of engine.

My cooler was plumbed AFTER the radiator like recommended, and takes 14 deg f out before it goes back to trans.

I can drive hard on a 100 deg f day at 100mph with A/C on and it gets to 193 engine coolant and 193 trans temp.

So, the trans auxilary rad not only cools trans, but can cool the engine also.

Everybody got an opinion here , but nobody has an auto.

Now the thing about 2 stoke keeps confusing all of us.

I hope you don't put 4 quarts of 2 stroke inside engine becuase you seem to say that.

Use good 0w40 like Mobil 1 or Castrol edge in your engine, and put about 4 oz of good synthetic FD 2 stroke in a 10 gallon fillup or up to 8 oz in 12 gall fillup IN THE GAS before filling.

 

Hello 40w8: Thank you for your concern about my RX-8 auto. I think you are correct about the cooling of one part of the system having a positive affect on the other part. [tranny-engine / engine-tranny]

As for oil, I think you are on to something there. I'm sure that any full synthetic 0W-40 oil would be 99% equivilent to any good synthetic 2-cycle oil. (low ash, easy burn, good wide viscosity curve.) But would be a lot cheaper.

And I can get the benefits of the 2-cycle oil protection boost with the few ounces added with a gas fill up. [again... saving money, just a bit of work.... LoL.]

I like your idea, I think I'll get the result I'm looking for at nearly half the cost.

Thank you, I didn't even know 0W-40 existed. (I though 5W was the lowest.)

Cheers, -Tim Ganstrom


I did some light reading...
https://mechanics.stackexchange.com/...nt-engine-oils

SAE viscosity grades ? viscosity table and viscosity chart

 

I was an Exxon fuel distributor dealing with fuels, engine oils, industrial oils, and sometimes lab analysis of those.

I used Mobil 1 10w30 as my RX8 first fill since I didn't even know about 0w40 oils until 2008, and they were out in maybe 1996.

When I was working I didn't have time to see straight, but I retired early, and best thing ever.

I've gotten an amazing amount of info from this RX8club, and read BITOG.com for oil analysis.

After some of that 0w40 just looks right, and it;s dirt cheap.

Many people read 0w40 as thin, but it's same thickness as Mobil 1 10w30 at 32 deg f, and DOESN"T THIN OUT AS MUCH as it gets hotter so stay thicker at working temp.

Some body showed some German made Ravenol FD here which I'm gonna buy a gal., and it's about as thick as engine oil, but that doesn't necessarily matter for 2 stoke since it's gonna get all thinned out.

I'm impressed with the smokeless synthetics that have PIB, and I think will help burn up deposits.

My plugs looked pretty clean for 32k miles.