Transmission shudder

What would cause a 1993 Chrysler concorde to shudder when slowly accelerating through 40 mph? It does not happen if accelerating to get to interstate speeds. I t also happens sometimes when maintaining a constant 40 mph. Local tranny shop suggested sensor problems.

There are parts house shelves filled with “snake oil” additives for automatic transmissions and many are quite good. In fact, there is a product just for the shudder,which is often the lock-up clutch. Go to any of the McParts stores and look over their offerings. I have never seen any damage from the additives and often they improve the driveability.

Sounds just like my Expedition a few years ago. I changed the fluid & filter and it hasn’t done it since. Fluid change should be your first thing to do.

Is there any way to actually test the effectiveness of these “snake oil products”? Other than putting it in and saying “well I guess things are better” These products are all over the market for just about every system. I guess I am talking about somekind of Consumers Report study or I got it this is a job for Myth Busters.

I agree, and I think its called torque converter shudder. I had a 1999 Ford Taurus that did the same thing. My mechanic wasn’t hopeful, but we flushed the old fluid out and refilled it. It went away. Try it… its the cheapest thing to try and since its a 93, it probably needs a fluid change anyway. Tranny fluid needs periodic changing just like your engine oil. Check the owners manual for the recommended change interval, and the correct fluid to add.

Make sure you put the right ATF in it. Chryslers are very sensitive to their own ATF, usually ATF +4.

As you were. How did I ignore the possibility that maintenance was in order? If due for service, that alone could cure the shudder.

And as for testing the products, it would be helpfull if someone tested and rated all the products. Several seem to use the same or very similar chemical technology. They involve some detergent action which cleams the gum and varnish which often accumulates in transmissions and causes valves to stick and restricting fluid passages. Old Fords have often been presented to me with transmission not functioning after long periods of being idle but assured that all was perfect prior to the ‘rest.’ After adding any of several similar products and letting the engine idle, occasionally shifting through the gears, the trans would come to life. When driven, these Fords might not immediately shift correctly but within a hundred miles they usually were ‘as new.’ ‘Snake oils’ are not at the top of my list of popular products but a few are worthwhile and when a $10 experiment can often save a $500 repair I recommend that customers try it. And when servicing transmissions I include adding one of the snake oils which seems particularly good.