First off, I'm a noob to the forum, so thanks for letting me join!

Second, I was wondering if anyone can help me pinpoint my problem, or at least give me a place to start looking... (I have a 1999 Grand Caravan 3.3l V6)

For the past couple of days, my van has been shifting while I am driving. It will downshift from whatever gear i'm in. If i'm in 3rd it goes to second, and so on. It has also recently started going from any gear i'm in, into reverse! When it down shifts it just raises the RPM, and then goes right back into the proper gear. When it shifts into reverse, it makes a loud slam noise, then goes right back into the proper gear.

It seems to be some type of electrical issue... It does not do this all the time, I would guess maybe twice within a 25 mile drive. And when it's not doing this, it shifts and drives just fine, has no problem going into and out of gear. Aside from feeling it shift, on the dash it shows it going into another gear. Not only that, but my speedometer, and tachometer drop to 0 every now and then, then jump right back up to the correct readings... Am I looking at a computer issue?? Could it be that the tranny is going bad, even though it shifts fine the majority of the time?? I'm really at a loss as to where I should start looking to identify the problem. I don't have the money to have a mechanic look at it for 5 hours, then still not have anything fixed so PLEASE HELP me start somewhere...

Thank you!

 

Forgot to mention that I have checked the fluids, and everything is fine. I've kept regular maintenance on the van since i've had it (It now has 104,000 miles on it, and I got it when it had less than 80,000).

 

Welcome to DF

Try removing the output sensor and inspect it for metal. If you have metal on the sensor, then the rear planetary gear assy is coming apart. If no metal. Inspect the wires going into the output sensor. There has been a problem with the wires breaking inside the connector.

 

Are you seeing the check engine light? Check for codes either with a scanner (free at Autozone) or use the key cycle method. Does it have only ATF+4 fluid in it?

 

It could be a sensor which is more than likely. Since it is slipping and going back in gear. I would have said time for a rebuild but since it is slamming itself into reverse on it's own, It is more than likely a sensor.

Check them, ALL OF THEM, Just in case. Pull the pan and check it to. Make sure no metal is in there.

My father had to replace his transmission on his Suburban because of metal shavings costing him $1300!

 

I had a 3.3 liter Flex Caravan and I had similar problems. It turned out that the stupid sensor had actually broken off and was hanging by the wires next to the transmission. It should be fairly obvious to see. failing that, remove the sensor and check for metal particulates as this is an indicator of serious transmission problems.

If the sensor is fine, check the TCM, transmission control module. you need to hook it up to a computerr for that though. Take it to your local AAMCO as they will test it for free.

Good Luck.

 

Sorry for the late response guys, I was out of town for a couple days.

Today I replaced the Output speed sensor, and I'm still having the same problem... I did notice that there are metal shavings on the bottom of the old sensor, and I also noticed that the solenoid pack is leaking. Could it be the solenoid pack causing the problem?

 

So by your comment, I assume that I'm looking at a rebuild regardless of the problem now?? I knew once I saw the metal shavings, it was not a good sign...

 

Nope. No check engine light on. I had my mechanic plug in and check for codes, and he came up with nothing.

 

hello...a big leak in the solenoid pack could be the cause of those problems...