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Dancing transmission

1993 Dodge Caravan transmission does a ‘bunny hop’. Lower gears are fine. (RPMs advance and fall normally when trans works.) Gets to 45 mph with (RPM steadily going higher) then hops and jerks. Sometimes it will go into the higher gear range, sometimes not. Sometimes stopping and retarting the van will fix the problem. Seems to concide with the check engine and check guages lights. If they are on-trans dances. If they go off-trans works. Once trans gets over it’s dancing, it shifts fine. I don’t think I need a trans since it does fine when it does work. It seems to be an electrical componet. I don’t want to put in a new or rebuilt trans and find it is an electrical problem. Mice ate some wiring about 12 years ago. Thought I had repaired all of the bitten connections. I LOVE my ratty little van. Any ideas? I am a 61 year old lady with no real car repair knowledge. I’ve been taken advantage of before. I don’t want to get taken this time.

The next time that the Check Engine Light (CEL) is lit up, go to an auto parts retailer and have them scan your OBD system for stored trouble codes. That will be the start of the diagnostic process.

Since this vehicle has the older OBD1 system, some parts retailers will not be able to scan it. Make a few phone calls to find out who in your area can determine trouble codes from an OBD1 system, and then drive there directly next time that the CEL lights up.

This could be an engine-related driveability problem just as much as it could be a trans problem, but without the code(s), everything at this point is just guess-work.

I doubt that you’ll find an auto parts store with a scanner that will do the OBDI codes. Try this instead: turn the key on, off, on, off, on. (The “on” part would be to the point that the dash lights come on but the engine doesn’t crank, the off part is all the way off). Watch the check engine light and it should start blinking at you. Pause. Blink again. Pause…

Count the number of blinks between pauses. Those give you numbers representing fault codes. So blink-blink …pause…blink-blink-blink …pause would be 23. All of the codes are 2 digits. The very last code it blinks out should be 55 - which just means its the end of the codes.

This is an imperfect method but it is fast and free. Do it a couple of times to double check yourself and post back the results.

You might have to do this at a time that the van has acted up.

A transmission shop needs to scan the TCM for trouble codes. The TCM will store 2 digit trouble codes. Let us know what trouble codes come up before you go approving any kind of work on this trans.