I am having an intermittent problem with my auto transmission in my 70 442. Most of the time it shifts great. Sometimes when I get on it from a stop it will not shift out of first. It will stay that way for a while. If I stop the car, put it in park and shut it off and start it back up it will shift fine. I have been driving it like this for about a year and it has happened about six times. Like I said most of the time it is fine. I have changed the filter and fluid. Check the level. I brought it the local tranny shop. The guy drove it and said it shifts fine. Figures it would not do it when he drove it. I just don't trust driving it too far because of this. Any Ideas? Thanks, Bob

 

Sounds like either a valve body thats gummed up or a governor that possibly leaks or is worn. Whats the fluid look like? When it does shift, is it a firm shift or does it slide into the next gear? When you had the pan off for the filter change how much junk was in the pan? Is this a TH400 or TH350 trans? Is the kickdown cable connected and adjusted right?

 

Get a governor weight/spring kit from B+M, follow the instructions, and tailor your shift points accordingly.
You might need a magnet to find the broken spring in there.

 

The fluid looks good. When it shifts it feels very smooth and firm. It doesn't bang into gears and it doesn't feel like it slides. There was some dirty stuff in the pan. No chunks or metal that I saw. It is a TH400. I'm not sure how to check the kickdown cable to see if it is adjusted right. I did change the modulator and made sure the vac line was good.

 

I think I will get the governor kit. I don't know if it was ever changed. I never changed one. Is it fairly easy because I don't want to screw it up?

 

Before doing the kit, check the kickdown switch on the carb - could be hanging up or dirty, causing it to stick when hot.
Governor kit is fairly easy!

 

The kickdown switch could be mounted on the gas pedal also. Sticking in first gear might be a modulator valve going out.

 

You wont find a detent cable, TH400 don't use one.

The governor cover is on the pass side of the trans behind a square cover with 4 bolts. When you remove the governor from the case make sure the gear is in good condition, and make sure the bore the governor rides in isn't chewed up.

The kickdown switch is on the gas pedal inside the car.

 

Ok, Iv'e Checked the modulator line and replace the modulator. I replaced the governor. I replace the kickdown switch today. Pulled out of the driveway and it shifter fine all around town. Got on the highway and gunned it and no shift. Pulled it over put it in park and tried again, no shift. Pulled over turned her off and restarted it. Shifted fine all the way home. What do you think? Kickdown solenoid?

 

So it's staying in first?

 

Yes.

 

I wonder if it could have something to do with the vacuum line to the modulator? (wild hair *** guess)

 

I blew out the line and checked for vacuum.

 

I know the boys here are not
the biggest fans of pour in stuff.
But I have used Trans-X before
with good results for sticking valve bodys.

Just make sure that you don't overfill.
You can crack open the bottom line
on the radiator to drain a little out before
you put it in.

 

Thanks, At this point I don't think it would hurt to give it a try.

 

How much rubber line is on the vacuum modulator vacuum line? What are the odd the line is collapsing once the engine gets hot? Line collapses, cuts off vacuum supply to modulator=no up-shifts. Just an idea.

 

My 400 was doing the exact same thing a couple of days ago....I replaced the vacume modulator line and the problem was fixed..and I was about to rip the darn thing out...and the line looked original..as matt69 said, my old line must have been collapsing ...

Ted

 

Even if the kickdown solenoid was stuck in kickdown position, the transmission should still shift at the highest it can out of 1st.

I am thinking that possibly the vent is clogged and that the box is getting pressurized. Check the vent for dirt around it. It seems that there is an issue with hydraulic circuits getting stuck. I am thinking that the 2nd gear band is stuck in the released position. In Dr, the one way sprag provides 1st gear, but it is up to the 2nd gear band to engage and take over for the sprag, which free wheels in 2nd and 3rd.

A simple test is to start in "1", then manually shift to 2nd. If it shifts to 2nd, then the issue seems to be in DR range, and this points to sprag and band.

 

Pulled out of the driveway and it shifter fine all around town. Got on the highway and gunned it and no shift.

So it shifts fine now? OR it won't downshift now??? If its not kicking down check for voltage to the switch. and if its getting all the wayto the trans. when pushed on.

 

I will check the vent this weekend. Next time it doesn't shift out of first in DR I will try putting it in first and then manually shift to second and see if it shifts.

It happens intermittently. Sometimes it shifts great the whole day out. Sometimes it will stay in first right out of the driveway. Most times it happens when I get on it a little. Once it happens I have to put it in park and shut it off, restart it and it shifts fine. Then I baby it till I get home.

When I am cruising on the highway it does downshift properly when I get on it.

 

How's the fluid look, color, smell funny? Is it full?