1994 Dodge Shadow Issues shifting

Jeaux · Posted at Wed Sep 02, 2009 7:42 pm

Transmission problem
1994 Dodge Shadow 4 cyl Front Wheel Drive Automatic 130000 miles

I think this is really strange. I'll put my car into drive, and when it reaches the point where it is supposed to shift to the next gear, it won't at first, I'll keep driving, not getting any faster and it sounds like the engine's really working, and then suddenly it will, quite smoothly. Then then it has no problem in the next gear. Further, when I stop, I have to put it into park then back to drive, so it'll return to first gear, or else it won't shift back on its own. I went to get the transmission fluid changed, but they wouldn't because it didn't need it. No noises or grinding either.
So, it shifts fine, just whatever tells it to shift isn't doing its job.

caradiodoc · Posted at Mon Sep 07, 2009 12:35 am

My '88 Grand Caravan did the same thing. After many years of never hitting wide-open-throttle, including many trips pulling an enclosed trailer that's bigger than the van, the problem started right after I DID hit wide-open-throttle. No downshift, (you don't have to put it in park, just put it down to first gear), delayed upshift, etc. Add to that, I only changed the fluid once in 213,000 miles.

Most likely there is a buildup of varnish in the valve bores. In my case, the problem gradually went away over a couple of months. Logic says it's the throttle valve that's sticking because that's the one affected by wide-open-throttle, but the governor valve is partly responsible too. If it sticks just a little, the transmission will think the car is still moving so it won't downshift.

If it doesn't improve in a week or two, try a cleaning additive. I've heard of Sea Foam, but never tried it. Just be sure it's something you can leave in. There are a lot of cleaners that will dissolve varnish but must then be drained out with the old fluid. You want a cleaner that won't affect the fluid's ability to lubricate bearings and seals.

caradiodoc

Jeaux · Posted at Fri Sep 18, 2009 2:39 pm

Thanks! Would that be an additive for the fuel system? Seafoam requires it to be removed after. Would it have to be a heavy duty additive like seafoam, or would a simple additive that you can buy at the store do the trick for this kind of issue? I got a bottle of STP fuel system additive, and I haven't noticed any results yet, but I've only used a about a quarter of the gas I put in with it. Just wanted to make sure I was treating the right part.

Thanks.

caradiodoc · Posted at Fri Sep 18, 2009 2:56 pm

??? Fuel system additives are for the fuel system, and on Chrysler products, they don't do much to help a running problem. You have a transmission problem so you need an additive for the transmission. You'll have to read the labels on the bottles or ask the guys behind the counter at the auto parts stores what they recommend. I've never used "mechanic in a can" on any of my vehicles, but I've heard good comments about Sea Foam, that's why I suggested it. I know there are a lot of other products out there.

By now, the shifting problem should have started to improve on its own. If not, I don't think a simple fluid and filter change will help. I'd try a transmission flush where they add a strong detergent first to the old fluid, then use new fluid to push the old stuff out. It's a lot more expensive, but very effective. They also add a can of seal conditioner to the new fluid.

caradiodoc