What causes TH350 transmission to hesitate on shifts?

What causes TH350 transmission to hesitate on shifts?

When it came time to find out what the common formalities are with this transmission, both mentioned the “late shift” issue. Occasionally, the TH350 will hesitate on shifts, and this can be caused by a number of things, including; a vacuum line leak, a blown modulator, or the bolts on the hold-down plate not being tightened down securely.

Why does my Chevy TH400 run low on line pressure?

This will fool the gearbox into recognizing low throttle, and it will run low line pressure. As a result, it will slip and burn clutches. Other common problems our experts experience in both the TH350 and TH400 is the amount of automatic transmission fluid (ATF) in the vacuum modulator.

Why does my Ford 400 not upshift to high RPM?

I had a simular problem with my 400, it would not upshift till very high RPM, turned out being the kick down solenoid, it leaked. The trans thought it was in passing gear all the time. Maybe you have a check ball rusted in one of the valleys not letting fluid by. Have to drop the valve body and tear it apart.

What happens when downshift solenoid does not work?

If the downshift solenoid fails or has an issue, the vehicle may experience late shifting when slowing down. The transmission may stay engaged in a higher gear for an extended period of time when it should be downshifting. This will cause the engine to over rev, and may put additional unnecessary strain on the engine and transmission.

Why does TH400 not downshift to 1st off road?

If it won’t kickdown to first when you mash the throttle, it is probably because the kickdown solenoid isn’t getting a signal or isn’t working properly. The kickdown on TH400’s happens when 12V are applied to the terminal coming out the drivers side of the trans. This is usually hooked up to a switch on the gas pedal.

Is there kickdown solenoid on 1970 Olds TH400?

I have a 1970 Olds with a TH400 and it shifts as smooth today as in 1970. Dropped the pan a few years ago, nothing noteworthy on the bottom, new filter, cleaned pan and buttoned it up with fresh fluid. The Olds doesn’t have the kickdown solenoid which I believe runs from a switch on the carb. linkage, Any TH400 transmission has a kickdown solenoid.

What are the signs of a bad Shift Solenoid?

One of the first symptoms of a bad or failing downshift solenoid is erratic shifting. If the downshift solenoid has any issues, it may cause the vehicle to behave erratically when downshifting. A bad or failing solenoid may cause the vehicle to experience hard or erratic shifting when slowing down or coming to a stop.

Where is the solenoid on a TH400 transmission?

Any TH400 transmission has a kickdown solenoid. Earlier versions had 2. 1 for the kickdown, the other for the variable pitch convertor. Just a tad more detail, that solenoid terminal is mounted on the left rear of the transmission case, with a single spade, the only wire that goes to it.