TH-350 wont shift?

[TheMonteCarloKid]

So i dont drive my car much at all. Its not registered or insured so a spin around the block once every few months is all she gets. Just took around the block and she doesnt seem to want to shift at all. Its a 355 small block with a TH350.
Any ideas on what the problem is? My thoughts are maybe low on fluid in the transmission or torque converter.

 

[-83MONTESS-]

Check your fluid level first. Make sure its warmed up and still running while you check it. My TH400 has a leaking front pump so if it sits for over a week without being driven it has a habit of emptying itself in the garage If I drive it atleast once a week it doesnt leak nearly as bad. With it being winter you should see my garage floor

 

[my86442]

I agree, check your fluid levels, if its low it wont shift like it should. that or with it sitting all the time, you could have a valve sticking or something in that nature.

 

[TheMonteCarloKid]

thanks! i'm sure thats it. it does have a slow leak. but over time it does empty all over the floor. I'll check it out tomorrow

 

[timo22]

Although proper fluid level is a must, I would check your kick down cable. Make sure that it is not stuck. This would keep it from up shifting. More than likely it is a vacuum or modulator issue.make sure you have good vacuum to it.it is located on the back of the transmission passenger side. A lot of times you can pull the vacuum line off it and if you see any fluid, the diaphragm is shot.if everything checks out,it could be the governor which is located under the round cap on the drivers side. Pull it and check the plastic gear on the end of it. If the gear looks ok ,move the wings to make sure the valve is free. These are the external things to check for shifting..good luck. Timo22

 

[DRIVEN]

More than likely it is a vacuum or modulator issue. Timo22

That would be my first guess too. If the modulator fails or (more likely) the vacuum hose comes off at either end, the transmission thinks its at WOT and won't want to shift until the governor forces it to. If there's any fluid inside the modulator hose then the modulator needs to be replaced. They're cheap and easy to swap.

 

[anthonychacon80]

Agree. Modulator. The modulator MIGHT be fine, the hose connection might be cracked or disconnected. Replace the hose and modulator if the fluid is fine. DO not drive it again till you do, you may burn up your transmission revving it that high without shifting.

 

[TheMonteCarloKid]

I think i found the problem. The vacuum line off the passenger side is only about six inches long and is not connected to anything

 

[TheMonteCarloKid]

 

[TheMonteCarloKid]

where is the vacuum line suppose to hook up on the engine?