76, 383 Stroker, TH350 trans. Ok here's what I have.

Last Monday I morning I drove out to the Golf Course, (4 mi., 55 MPH), suddenly the car shifts down to second gear WTF?? I manually shift to second then back to drive and the car shifts back to drive and back to 55 MPH. 1/4 mi down the road the car has nothing as if I put it in netural but shifter still in drive, now I'm coasting.

I coast down to about 35MPH, shift to netural then down to second and I have gear again. I limp into the course and park. 2 min later I leave to go back to town, car goes into gear fine (drive). I pull out onto the highway and begin to accelerate, at 45MPH it shifts it's self back to second. I shift down to second then back to drive and I have drive again. I begin to accelerate and now I sense a little engine rev. and slippage. Back to second and limp home to the office.

Now its noon I get in the car and drive it around to the garage, put it in park to open the door and when I get back in, shift to drive I have nothing or any other gear. Grab my truck and go to lunch.

After lunch I get back in the car and put it in gear, I have gear and drive it into the garage.

Sorry for the lengthy explaination but I wanted to give the whole story. Is my tranny going south?? Clutch packs?? I checked fluid and its all there, no particles but when I wiped the dipstick onto a tissue it left a slight grey stain on the tissue.

All responces are appreciated.

 

Best guess? It's trash.

 

As its a TH350 with a vacuum modulator on the rear of the transmission I would check to see if the short 1/4" hose is still plugged onto the modulator. Over time the short hose gets oil soaked and swelled and then it'll slip off................ then your transmission does all kinds of weird things. Its also possible the hose became disconnected from the fitting in the #8 runner on the intake manifold. When replacing those hoses always use fuel hose because its able to tolerate oil and heat.

If the hoses are still connected and not split or otherwise damaged I suggest pulling the oil pan and see if it has a lot of crud in it. I believe the TH350's have fine wire mesh screen filter and it may be plugged. Also the TH350's have a pull cable attached to the bell crank on the left side of the carburetor and the cable may have broken or become disconnected.

 

The first place to start is checking your fluid condition and level.If the fluid is black or smells burnt it is time for a rebuild.If the fluid isn't bad then check for leaks and proper fluid level.Then you can check out the modulator and other potential fixes.

 

If the trans has a vacuum modulator (as opposed to a T.V. cable), that is your most likely problem.

Otherwise, the trans has probably had a major failure and needs to be rebuilt or replaced.

 

Hey tobroketoretire, I can't thank you enough. The vac modulator was it. $12.00 O'Riely Auto.

I had thought about that component but just didn't think that little guy could screw up the tranny sooooooo badd. Amazing! I was really bummed out with the Labor Day weekend around the corner and the car out of comission. Wow.

I swapped it out first thing last Sat. morning and now have 150 miles on it with no problems. I wanted to make this post to close the subject and let everyone else know. . . If your tranny suddenly starts acting up don't hesitate, change the vacum modulator before you do anything else.

Thanks!