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Is my transmisison broken?
February 22, 2005 3:53 PM   Subscribe

Another car question. I have a nine year old automatic car with a seven year old engine. Lately in the cold when I put it into reverse and put on the gas, the car just revs. Then after a little bit I feel a shifting clunk and the car is in reverse. I back out of my space and put it into drive at which point, if it's cold enough, the same thing happens. I coast in neutral, accelerator does nothing but rev for a little while, then I feel it push into gear and can go forever, including to full stops and on again the whole day. Even on cold days, after being parked it works fine. When it's not cold, this doesn't seem to happen. So 0.5) is this related to my transmission at all, 1) is my transmission on the way out, 2) is it more dangerous than I think to drive it, and 3) will I need a whole new transmission or just a minor repair?

I'm guessing that the gears are spinning, but just not "catching" when it just revs, though I don't understand why it wouldn't do the same thing from a full stop. So my best guess is that the teeth on my gears are just getting pretty worn down. Lots of mileage on the car, though I must say I am pretty gentle with it. Please enlighten me -- though I am capable mechanically, I really don't spend any time thinking about cars.
posted by ontic to Travel & Transportation (18 answers total)
 
My car does something similar. If I shift into reverse or drive from neutral and wait awhile, I can feel it catch, and then I can move without the revving. Otherwise, I can do what you do, but I always had the feeling that it wasn't very good to do to the car. So, I usually break, shift, and wait long enough after shifting to feel the gears catch. I drive a 2001 vw passat wagon.
posted by odinsdream at 3:59 PM on February 22, 2005


did you check your transmission fluid level? You may need to add some fluid.

iirc, when I had my car transmissions rebuilt, reverse was the first gear to go which was the sign for it needing the rebuilt.
posted by thomcatspike at 4:14 PM on February 22, 2005


My car did something similar. Note the use of past tense. It did that for a year or two. Then one day, it would seem okay except that it didn't seem to want to shift from the second highest gear to the highest one. Then it stopped altogether. Then it wouldn't even shift out of low. Then I drove it to a transmission shop and never drove it again.

If I had it to do all over again, I would have found a decent tranny shop and paid probably $200-300 or something for a fluid change and adjustment, but I don't know if it would have made things any better in the long run.

Time to sell your car to your brother-in-law.

Transmission Haiku:

First, second, then third
First, second...second, then third
Only first is left
posted by Doohickie at 4:17 PM on February 22, 2005


iirc, when I had to have several of my cars automatic transmission rebuilt, reverse was the first gear to go which was the sign for it needing the rebuilt.
posted by thomcatspike at 4:17 PM on February 22, 2005


Yeah, ontic, what kind of car is this? I've got a 97 Jetta that's doing the same thing, with odinsdream's Passat, I'm leaning towards thinking it might be a VW issue.

Its more annoying than anything else to me, except when it wouldn't go into reverse and I was on a hill.

Check fluid levels (my guess is you have already) and then take it into the shop to see what they have to say. I do know its ridiculously expensive to do a transmission flush and fill on a 97 Jetta.

Good luck.
posted by fenriq at 4:20 PM on February 22, 2005


I've really never thought twice about this. In my experience, all automatic transmission cars I've used had a bit of lag-time between when you shift and when the gears actually engage, and during this time, the car can roll. I wasn't under the impression that this was abnormal, but if it is, I'll have a repair shop look at mine. I've gone for several involved checkups, and I've always had a clean bill of health, so to speak.
posted by odinsdream at 4:25 PM on February 22, 2005


Hmm. Make and model would have been good information. I have a completely different car, a 1996 Plymouth Breeze. I had the transmission fluid checked fairly recently. But I don't think this normal behavior. We're talking about a 30-60 second wait between putting it into reverse and reversing.
posted by ontic at 4:50 PM on February 22, 2005


Does the car whine when you're putting it in gear and also when you're travelling very slowly? How fast does it travel when your foot is off the gas and you're coasting from a stop on level ground?
posted by SpecialK at 5:04 PM on February 22, 2005


It could be that the servo for that gear is stuck/wants the fluid warmed up before it functions. Try taking it to a dealer/tranny shop & have the transmission flushed (make sure their flush also takes care of the radiator & torque convertor).
posted by Pressed Rat at 5:04 PM on February 22, 2005


We're talking about a 30-60 second wait between putting it into reverse and reversing.

Ah, I see. My lag is maybe 3 seconds.
posted by odinsdream at 5:22 PM on February 22, 2005


The car does whine a little bit when stopped. Haven't noticed it while going slowly.

Thanks for the suggestion, Pressed Rat. That sounds just complicated enough to work.
posted by ontic at 6:55 PM on February 22, 2005


This from Hubby, a former mechanic: check tranny fluid levels first (as suggested above), as it sounds like the torque converter (the fluid coupling between engine and tranny) may be draining. This would indicate a weak main hydraulic pump, but it's not too likely since the car runs fine once it's warm.

Another possibility is that the bands (these are clutches that hold a ring gear inside a planetary gearbox) need to be adjusted. Your concern about gear teeth getting worn is not really the right way to think about automatic trannies. Automatic transmissions are based on planetary gearsets, meaning that all gear teeth are always engaged. The shifting of gears is really a result of hydraulic pressure holding either the ring gear or the planet gears stationary. This is done with clutches and bands, which hold the planet and ring gears respectively. The clutches and bands are what wear out, not the gear teeth. If it's truly shifting smoothly and solidly when warm ("no long shifts" is how mechanics describe this), then your clutches and bands are probably fine.

Hubby suspects your true problem is in the shift selection valve. For example the cable might have stretched a little, not allowing the tranny to know what gear it's in. Hubby thinks this valve is "hanging" between the gear selection positions. This is a simple adjustment. A more complicated problem could be in the servos as mentioned earlier. Servo problems are usually the result of contamination of the tranny fluid by metal particles from the slipping clutches and bands.

It's not dangerous to drive in this state if it is in fact shifting fine once warm, but it could be expensive since the slipping clutches and bands will burn up, requiring another rebuild. The longer you let it slip like this, the more likely it will be expensive later on.

Disclaimer: there's no substitute for hands-on troubleshooting. Go see your friendly mechanic.
posted by Quietgal at 10:20 PM on February 22, 2005


When you start up, do you let the motor idle for 20sec before you put it in gear?
(60sec or even longer if it's below freezing - and after you put it in gear idle a bit more)
If trans fluid level is good (hard to tell on some cars - check the owners manual and follow all directions)
and it still does this, you may need new transmission fluid and
new filters in it. Any good transmission shop should be able to fix it fast.
posted by Charles the Friend at 10:40 PM on February 22, 2005


I had the exact same problem last winter - sit in the driveway with the brake on until I felt Reverse catch, back (weakly) into the street, cross my fingers nobody came along until I achieved forward motion and some amount of speed, which took a while, and by the time I got to the end of the street everything was fine and stayed fine all day. On really cold days (in the 20s here) I might have to let it warm up for 10 minutes in the driveway, though.

Fluid and filters did the trick. It's a 15 year old car, and I feared the worst, but it wasn't a big deal.
posted by Lyn Never at 6:52 AM on February 23, 2005


Thanks for all the helps everyone -- and especially for that amazingly detailed answer from Quietgal and Hubby.
posted by ontic at 7:00 AM on February 23, 2005


Glad to help!
QG & Hubs
posted by Quietgal at 8:19 AM on February 23, 2005


When you start up, do you let the motor idle for 20sec before you put it in gear? (60sec or even longer if it's below freezing - and after you put it in gear idle a bit more)

Why would one do this?
posted by five fresh fish at 9:18 AM on February 23, 2005


You probably have the 41TE a electronically shifted 4 spd transmission. This transmission has no hydro activated bands. Common problems (and solutions) are available at allpar.com.
They range from changing the fluid, checking plug connections, thru replacing an incorrect filter to rebuild required.

If the problem occured after the fluid check, the checker probably topped the transmission up with the wrong fluid. You must use the correct 7176 ATF+3/4 fluid in this transmission! Even a couple hundred mil of Dexron will cause poor performance and destroy the clutch packs in a 41TE in as little as 10K kms.

Best bet if you have any doubt of the current fluid in the car is to take the car to a dealer and have them change the fluid and filter and initiate a retrain of the computer. Pre 96 41TEs have a service bulletin out advising an updated firmware.If you car was actually made in 95 as a 96 model you may need this upgrade.

I can't stress enough that non 7176 fluid will eat these tranmissions up. It is far and away the number one cause of 41TE problems even surpassing overheating.
posted by Mitheral at 12:03 PM on February 23, 2005


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