reatta transmission th440-t4 malfunction

[thaddeus]

bought 1988 reatta, sight unseen, found that the transmission shifts great all the way up the gears, but bangs into second gear on the way down. someone told me that it could be a vacuum line or modulator. i can't find a broken line and am not sure where the modulator is. can the problem be something else? i also hear a rattling noise between the trans and the motor which goes away when i rev the engine. is this part of the problem? other than that the engine sounds strong. it has approximately 160k on it.

[Guest EDBS0]

Rattling noises most often come from the heat shield on the cat which has become loose. Use a large stainless steel gear clamp to secure and stop the rattle.

From my limited experience still sounds like vacuum leak or bad modulator.

[2seater]

A common place for a rattle at idle is also the vibration damper at the front of the engine. The rubber deteriorates and it rattles. The modulator is at the top front of the transaxle, and the vacuum end faces straight at the front of the engine. If you trace the two small steel vacuum tubes from the vacuum block on top of the manifold, they run down by the upper front "dogbone" mount and turn to the the drivers side. One goes to the modulator and the other goes to the charcoal canister for the fuel tank. The transaxle does have a pretty firm downshift when coasting down at around 14 mph. It should be smooth otherwise.

[thaddeus]

thanks for your response. the noise or rattle sounds like a centrifical type noise, it kind of reminds me of a loose bolt i had in a fly wheel at one time with another car. it quiets down after the engine gets hot, but you can still tell that it's there. it comes from the drivers side of the motor. any thoughts on that?

[thaddeus]

thanks for your response. i followed the vac lines to where you said and believe that i found the modulator. i pulled the vac line off the modulator and got a change in the rpm's. can a modulator hold vacuum and still be bad? (2) the noise is comming from the drivers side of the engine and quiets down when the engine gets hot. it almost sounds like a loose bolt in the fly wheel or torque converter, is that possible?

[padgett]

Yes but unusual unless someone had the engine or trans out. Think what you are referring to are the three bolts that connect the flex plate (flywheel) to the torque converter. Haven't looked for a few years but believe our '90 has a plastic inspection cover under the flex plate that can removed giving access to the three bolts. They go from the engine side of the flex plate, through the plate, and into the TQ.

You will need to rotate the crank until each bolt is visible. My FSM says each is torqued to 46 lb-ft. If I had that kind of noise in that area, I would check it out immediately.