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Would like to narrow down Automatic Transmission Problem

I have been commuting in a car that was given to us a couple of months ago. I drive for about an hour in the morning, and the same on the way back.

During that time, I have never experienced anything like what happened when I drove the car for 5 hours to the beach this week.

After about an hour or so, I had to stop and get doped up on caffiene for the rest of the trip. I had gotten off the highway, and as I slowed down for the light, it was like the transmission was engaging and disengaging over and over, causing the car to lurch several times before coming to a stop. More of the same happened as I navigated to the nearest gas station.

After I had gotten my drug of choice, I hopped back into the car to head down the road. I was hoping the lurching would clear up. It did seem to be fine, for the moment.

The next (related, I believe) thing to bother me was the car losing power while at highway speeds. Again, this happened after I had been driving for a while. If I was ambling along at 55, for instance, and I hit the gas to gradually accelerate to 70, it would switch to some weird lower tone and just not have the power it normally would. If I backed off the accelerator, it would slip back to normal sounds at some point.

Fortunately, the roads I was traveling were not very hilly. I think I would have been in trouble if they were. Furthermore, I can’t remember if the low speed issues happened first, or the high speed did.

It’s almost like the automatic transmission version of a slipping clutch, it seems. With the difference being that it doesn’t seem to do it just after starting.

I checked the fluids during the trip, and all seemed okay, but I’m sure I didn’t check it in the right way. I think I remember that you’re supposed to have run the car for a certain amount of time, then do something else right before checking. So I am not exactly sure the fluid is at the right level. Obviously, that will be the first thing to check.

But if that’s okay, what should I do next? Just a simple fluid change? See if that fixes it?

1993 Chrysler New Yorker 5th Ave

190,000 miles

Could be some kind of vaccuum leak, cuz as soon as you take the load off of it, it stops doing it. Get a vaccuum guage and do a vaccuum check. By the way, to check the tranny fluid, warm the car up, put it in each gear for 5 seconds or so, then get out and check the dipstick with the car running. (take out, wipe off, put it back in and pull it out to read it.)

Well before someone berates you for not checking the owners manual, I will assume that you don’t have one. When you check the automatic transmission fluid, follow this procedure:

Get the car up to operating temperature by driving it around for a bit.
Park the car and move the shifter through the range (From park, down to low, and back up).
Pull the dipstick, wipe it off, reinsert it, and pull it back out. Check the level, color, and consistency of the fluid (if you’re not embarrassed, smell it, too).

If the car is not at least warm and running when you check the fluid, the dipstick won’t even be close to accurate. If you simply forget to slide the shifter through the range, it may be right or it may be off a little.

Your description of the problem is a little confusing, but the concerning portion is where you mention it acts like a slipping clutch. That tells me that it could well be a… slipping clutch. Automatic transmissions use clutch packs, bathed in transmission fluid, that are engaged hydraulically. When the clutch discs begin to wear, they may slip and generate heat (something that automatic transmissions positively don’t tolerate) which causes more wear and slipping until failure. A problem with the hydraulic portion of the transmission (which is electronically controlled) can lead to these clutches not being fully engaged, which again causes slipping and accelerated wear.

So first thing’s first: you need to make sure that it’s got the correct amount and type of fluid with the procedure that I outlined above. Then you need to take a look at that fluid and try to detect if it’s burned or contaminated. You can’t miss burned transmission fluid, it smells awful and has a deep red color. Wipe the dipstick on a cloth and look for dark grayish contaminant wiping off. A small amount is to be expected with a car of that age. A large amount is not a good sign.

What can you do? If the transmission is low on fluid, fill it immediately and see if that changes anything. Next, I would change the transmission fluid and filter. You don’t mention what / if maintenance has been performed on this car, but in my experience, American cars of this vintage rarely receive prescribed cooling system or transmission maintenance. Unfortunate but true.

That, to me, is the most logical way to approach then, good luck with it.

That sounds more drivability to me. I would let a drivability guy look at it first before condemning the transmission.


I agree with Transman and wild guessing a bit here, I’d consider the possibility of a failing fuel pump, failing fuel pump relay (which can be damaged by a failing fuel pump), failing automatic shutdown relay, etc.

At that age and mileage it could be near anything. I think this car also has a couple of wiring distribution terminals that should be inspected and cleaned. One is a junction block between the fuel pump and FP relay. The other should be near the battery so follow the positive battery cable to find this one.

If you suspect the transmission, and considering the symptoms, you need to make sure you’re checking the transmission fluid level correctly AND examine the fluid closely. If the fluid is brown or blackish in color and has somewhat of a burnt smell this means the trans is on the way out and a fluid change won’t likely help it.

ok4450 beat me to it! I would also suspect the fuel pump, and would suggest that this is a good place to start–after you have properly checked the transmission fluid level.

I too agree with OK4450 except for his last statement. I have saved two transmissions with a fluid change when the fluid was dark brown. In both cases, the drivability problems just began and the fluid was dark brown, not black. I do agree if you ignore it for very long, it will be too late.

One was my mothers car. She always took it to the dealer for service and according to their records, it had been changed twice, the last time was the week before. In truth, they never changed it, or did any of the other work they charged her for. Since I was just visiting, I didn’t have the means to change it myself. She took it to a transmission shop who wanted to replace the whole transmission. I sent her to another local mechanic who did the change and it never had a problem again. The local mechanic did all the maintenance after that and it went well over 100k after, it only had 40k when the problem occurred. 78 Mercury Zepher Z7 that required fluid changes every 20k.

The other was my daughters 03 Corolla, which Toyota say never needs changing. T 75k, the transmission began to shift very roughly. I changed the very dark brown fluid and it solved the problem. I did another change a little while later and again at 90k. It has 105k now and I plan on doing changes every 30k from now on.

I’ve had two cars that lurched and bucked as I was slowing down to a stop. It turned out to be a sticky switch for the lock up torque converter. The fix would be expensive, but disconnecting the wire was a good shade-tree repair. Incidentally, when the torque converter would lock up, it often felt like it was shifting into another gear. It may be possible that the other problem you are having could be related to the lock up switch.

I agree with the last two fellows. A problenm with fuel or ignition.