[71Formula]

I've got a problem with my th400 transmission, that I don't understand. Lets see if anyone here does. The car is already in the shop with the guy that originally rebuilt it. He's backing up his work, so I'm fine with it. As of yesterday he said he was stumped, but was still investigating... so here it is.

At ~35 mph or less I can let off the gas and manually drop it into 1st and the car freewheels when it shifts down instead of getting back compression. Also, when I'm cruising in 3rd gear and let off the gas it idles like its out of gear (same as manual down shift simptom), but then when I get back on the throttle it shifts down into 2nd and then quickly shifts back to 3rd. This causes a lot of unnecessary shifting and of course no engine braking so steep grades could be bad.

My guess is a bad torque converter causing the one way clutch to free spin both directions. One reason I suspect this is because I don't think the stall on the converter has ever been right and I think the bottom end power should be stronger too.

Any ideas? Like I said the car is already in the shop and I hope to get it back tomorrow or the next day (hopefully fixed). But I'd like to get some opinions, after all my tranny guys is stumped so far...