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Hello, my first post here. I am original owner of 2001 mdx, car has 212K miles on it. I had transmission rebuilt around 135k. Was driving somewhere a week ago at 60mph, took foot off gas and car downshifted suddenly, jerked me forward. Hadn't done this previously. Was able to get car to shift back to highest gear a few times but ended up where it would no longer do so. Was able to drive home 30 miles in lower gear, engine was turning around 4500rpm at 50mph. Took car to local transmission shop, tranny acted up the same way during the drive to the shop. Did free diagnosis, said problem was internal, would cost $495 to diagnose. He thought a repair could run from $1000 to $2000, possibly more depending on diagnosis. Given age and mileage on car, I didn't know what to do, so I told shop I wanted to look around before deciding, see if i could find another car to consider before committing to unknown repair costs. The shop said fine and that I could leave the car for a few days while exploring my options. I managed to find another car, went back to the tranny shop to tell the owner i wasn't going to do the repair and that I wanted the car back. He gave it back to me, I drove the car home, and it seems to be running fine again. I've since driven it 30-40 miles at various speeds and accelerations and i've been unable to duplicate the problem. Does anyone have any comment on my experience? I have a nagging feeling the problem may have been trivial, perhaps a loose electrical connection, etc, and the shop was being opportunistic, looking to do an unnecessary repair. Meanwhile, I bought another car from a dealer, part of the deal being that i trade in the MDX for a minimal amount due to the transmission issue. I love my old MDX and it's served me well, i would feel better about the whole thing if it had "stayed broken". Any feedback would be appreciated.
 

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Trans electrical problems would usually set a code. If check engine light was on when you went in and Off when returned, it is likely the garage reset the PCM. This may temporarily fix the problem.

If/when it returns, suggest getting the codes read at Autozone, etc and post code for further help.

Many electrical faults in trans are fixable.

good luck
 

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Thank you very much for your reply. The check engine light was still on when i picked up the car, it's still on now. Bought a code reader and saw the following: P0740, P0730, P0780 and pending P1399. Would this indicate that the problem is electrical instead of mechanical? I've driven the car 65 miles now with no operation issues. Any further feedback would be greatly appreciated.
Thanks again.
 

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I'm no transmission expert but I know that the MDXs have a lot of tranny problems, (the only reason I'm holding on to mine is because it has 85K miles) I would say take up this opportunity and get rid of the car without any disclosure of the tranny problems for a higher price. Seeming as you have a lot of miles since the thing was rebuilt, I would say it could probably need some costly work. I always say try checking all fluids for possibility of bad fluid causing sudden shifts
 

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Since that generation does not have the ability to tag the codes with date information, you can't know how old the codes are. Suggestion: Erase all the codes, and see how long it takes for any to come back. Repeat this a few times, and you will have a good idea of the seriousness of any problems.

The P740 code is often an indication of a real failure with Honda/Acura transmissions of that era. Very common with the V6 engine.
 

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These codes can indicate a hydraulic fault in the trans. It will take a very good auto shop to sort out the exact problem. Most seem to jump immediately to pull and repair, and indeed that may be necessary in your case.

I had a Acura TL that had persistent P0740 (torque converter failing to lockup). I lived w/ it for quite a few years before selling. It is however, very annoying to always see that Check Engine Light and you never know if another issue is present unless you scan for codes.

good luck
 

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Discussion Starter #8
Thanks again for the feedback offered!

I just cleared the codes and will drive to see what comes up. I've presently driven the car about 140 miles since I picked it up from the transmission repair shop, still no recurring issues as of now. If there is a mechanical issue, does anyone know how many miles it might take before it shows up again?I was reading about code P0740, saw that one possible cause of this code appearing could be a poor electrical connection. Therefore, my question(s): Is it possible in the free diagnosis, that the tranny shop might have checked and inadvertently "repaired" this connection? If a bad electrical connection generated P0740, could that lead to the other codes, 0730 and 0780 being generated as well? I realize the most likely culprit is an actual internal failure, but it's both puzzling and frustrating that it would be working so nicely now if there was a mechanical issue. I know the car didn't fix itself by hanging around a transmission shop for a few days! As before, any feedback would be appreciated. Thanks
 

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There's just no way to tell - there are SO many possibilities that shooting in the dark isn't likely to yield good results. Tranny problems can be electrical in nature, and an intermittent problem can come back 5 minutes from now, or never. A common problem with transmissions is metallic debris getting stuck in the (magnetic) shift solenoids. I once had a problem with a Volvo after towing a big (!) trailer cross-country and was getting ready to replace the shift solenoids... I let the car sit for a couple weeks while I was on vacation elsewhere, and when I came back, it shifted like new. My theory was that the residual magnetism "bled off" the shift solenoid, allowing the metallic particles that were in it to float away next time I started the car.

If it was my car, I'd just drive it and not worry until it DOES throw a code. If that happens, you'll at least have a chance at narrowing the issue down. Right now, not only can you not tell where the problem is, you can't even tell if there really IS a problem.
 

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On Acura TL, P0740 would occur when PCM detected that torque converter was not locked and speed was > 55 mph. I could manage to drive for some time w/o CEL, if I studiously kept speed below 55 mph. A fairly steep hill and 55 mph would immediately set the code.

Yours could be similar,.. or not.

good luck
 

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Discussion Starter #13
Thanks again to everyone for the feedback! Habbyguy, I am curious to know what ultimately happened to the Volvo? Did the transmission act up again? Also, to everyone, would it make sense to replace transmission fluid or to do a fluid flush or better to leave it alone?
 

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The Volvo went on to lead a productive and happy life. ;-) It was shifting fine when I sold it months ago. It's funny because I bought it for chump change because it HAD a transmission problem, but one I knew I could fix easily ($30 and 30 minutes changing a servo valve cover).

Personally, I'd suggest doing a transmission fluid change. It would cost about 5% of what replacing the transmission would cost, and might well fix the problem, since one of the most common problems with automatic transmissions is contamination in the shift solenoids, which happens when tiny metallic particles get pulled into the cores of the solenoids by the magnetism, keeping them from activating properly. A flush might just "fix" this problem - or might not if too much debris has accumulated in the solenoids. But since your problem "cleared up" I'd certainly do a transmission fluid change if it was my transmission.

My transmission is working just fine at 170,000 - and the previous owner has done about six drain-and-refills (about 3 quarts of fluid each time), so the fluid looks like new. Still, I'm planning to do a full "flush", which (if all goes as planned) I'll do when I install the inline magnetic filter I just ordered... This involves breaking the transmission cooler line to install the filter, so I'll just start the engine and drain two quarts, and add two quarts, then drain two more quarts, and add two more... until I'm sure I've pretty much changed 99% of the fluid... then I'll "fix the break" in the line with the filter. This method results in changing pretty much all the fluid in the transmission, rather than the 30% you get with a drain-and-refill... but if you do three drain-and-fills, you get pretty close to a full change (something around 60-70%).
 

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Mine did the same thing. Third gear clutch pack was worn out and the internals were digging in and temporarily locking the gear train. Driving it too much like that creates metal shavings that get jammed in places and damage the valve body. I got good at dropping it neutral when slowing down, but eventually conceded and rebuilt it.

[edit] Mine did it once in a while but started doing it all the time. When that happens, it's time for a rebuild. Having said that, the jerking that mine was doing would almost stand the car on the front bumper for an instant. It was very jarring. If yours isn't doing that, please ignore my thoughts...
 

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Glankford makes (all) good points - if your transmission seems to be slipping when a gear is (finally) engaged, it points toward worn out clutch packs, and there really isn't any option but to rebuild or replace the transmission. OTOH, if it feels like the transmission slips into neutral for a second or two between gears, and then "jerks" into gear (particularly if you don't think to let up on the accelerator), it would seem that your clutch packs are still OK.

The problem with Glankford's transmission was caused by a worn out clutch pack most likely, but the same symptom (jerking violently during a downshift) could be caused by less dramatic things, like a "normal" amount of metal in the fluid jamming a shift solenoid, causing the transmission to make some really, really bad decisions. ;-) BTW, "normal" in this case means "typical", not "good". A fluid flush might help.
 

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I had a 2001 MDX as well (I now have a 2006) my transmission went out 5 years ago, 1 year to the date after I had it rebuilt it went out again. So I had it fixed again. 2 years after that, I had to get a new car. I read after this that the 2001 had tranny issues. I still have it. It's sitting on the side of my house. I wish I would have just gotten a new one being that I ended up spending the same amount over the years repairing it.
 
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