Transmission won't upshift
 

Hi, guys and gals! I can't believe it's been 8 years since the last time I logged in to this Forum!

Well, my transmission started acting up. It won't upshift or downshift properly. This happened quite suddenly one day after I stopped for gas, then seemed to fix itself, and then a few weeks later stopped shifting properly for good.

I haven't been driving it for about a year, but the other day I had to use it, couldn't be avoided.

I found that if I left the line at around half throttle, the trans will upshift to 2nd at about 35 mph, and to 3rd at about 55 mph, just as if I was punching it into "passing gear." It never shifts to 4th, and on stopping, won't downshift to 1st unless I select Neutral, and then back to Drive.

The trans is a 700R4.

Any ideas what might be wrong?

Re: Transmission won't upshift
 

Have you checked the fluid?

Re: Transmission won't upshift
 

I know the 700R4 burns itself up pretty quickly if the TV cable isn’t adjusted properly

Re: Transmission won't upshift
 

Thanks, guys. The fluid level is good, and I had it and the filter changed 5 years ago, and I've put about 15K miles on it since then. I checked it first thing when this problem appeared. I have not been under there to physically check anything.

Re: Transmission won't upshift
 

Governor gear stripped/unit sticking?

Re: Transmission won't upshift
 

I have not been under there to physically check anything. This week I will. The TV cable and governor are the first 2 things...I just thought someone else might have experienced the same thing...

Re: Transmission won't upshift
 

Job #1 is to make sure the TV cable has no slack at the carb linkage. It's even OK to have just a slight bit of tension on it. It's absolutely necessary for the cable to start moving immediately when the throttle starts to open.

Check it with the choke open, so the throttle lever is not cocked slightly open by the fast idle cam.

Re: Transmission won't upshift
 

OK, thanks. I don't suppose anyone here has a factory service manual for this truck in digital format?

Re: Transmission won't upshift
 

Service manuals: http://67-72chevytrucks.com/vboard/s...d.php?t=545416

Re: Transmission won't upshift
 

Wow...that's amazing! Thanks much!

Re: Transmission won't upshift
 

Well, I messed with the TV cable, and at closed throttle it seems very loose, but pulling on it and snapping it like a guitar string made no difference; however, it seems like it's the #1 suspect, with the governor being 2nd, and then big problems follow that... I appreciate those manuals. Very kind of you.