Hey all,

I've got a '72 F100 with an automatic C4 transmission.

Got into the truck today, drove to work (at the end of the street) and when I got back in to run home for a minute, found that the truck won't shift into any of the Drive gears, but reverse seems to work.

I tried adding a little ATF, it seemed to help for about 30 feet, now nothing. Can't get it to go anywhere, except sporadically in reverse.

I don't have the cash for a new transmission, but have never rebuilt one either. Just wondering if anyone has seen this before, what I might be able to do, and whether I just need to save up the cash for a new-used replacement or try rebuilding the transmission (or maybe even replacing just a part or two inside?)

Ok, thanks a ton for any and all help!

Will

10/14/2010 4:10:19 PM

They can be found for cheap at nearly any salvage yard I think you'll be ok.

10/14/2010 4:27:51 PM

If you've never pulled an automatic transmission apart you probably can't fully appreciate how much of a complicated clusterfuck it is. I've assisted in a rebuild (it was a GM 4L60E). It's not like changing a headgasket or something. There are ton of tiny little pieces to keep track of and there are a few parts that require a special tool.

It sounds like a junkyard or Craigslist is your best bet.

10/14/2010 4:32:59 PM

They can be found for cheap at nearly any salvage yard I think you'll be ok.

10/14/2010 4:38:27 PM

That's what I expected, and clusterfuck was indeed the term that came to mind, and the situation I truly don't want to get into ;-)

I guess $200 for a used one is the way to go?

I can't imagine the swap itself would be too difficult, right? 5-6 bolts and two people? I don't want to pay anyone to do that for me if I can help it.

Anything else I should try before just giving up?

I mean, the truck has been driving fine until today. Except for the heavy clunking when shifting into gear that is . The guy I bought it from beat the piss out of it, so I'm thinking it was just already on it's way out.

Ok, thanks you all.

10/14/2010 4:42:25 PM

Quote :

"If you've never pulled an automatic transmission apart you probably can't fully appreciate how much of a complicated clusterfuck it is."

Quote :

"They can be found for cheap at nearly any salvage yard."

10/14/2010 4:42:54 PM

The truck will jump in and out of gear a little if I set the idle to ~500rpm, *some* of the time.

But, as soon as I hit the gas, it jumps back out.

I've poured a bunch of AT fluid into it, but just stuck as to what else to try before I scrap another *almost good* car to pay for a new transmission in the truck.

Any ideas?

10/14/2010 6:01:52 PM

Please replace it already

10/15/2010 8:42:45 AM

Well, if you were gonna embark on learning about how an automatic tranny works, that C4 is about as simple as it gets.

There's really not that much to an automatic transmission, but I don't usually recommend that you rebuild one if you've never rebuilt anything like an engine or maybe a manual tranny...it's not difficult at all, but it IS a little tedious.

Interesting enough is the fact it won't go into forward gears, but will go into reverse. Reverse requires the highest line pressure of any of the gears to go into, and is usually the one that shits the bed first. I'm wondering if you have a sticking governor or a bad vacuum modulator.

One thing I would try right off the bat: get you a can of Seafoam Trans Tune and dump in there. Follow the directions on the can. Also, are you checking the fluid with the engine running? I swear it sounds like you got no fluid, man.

10/15/2010 9:17:14 AM

I agree on the not enough fluid

10/15/2010 10:54:56 AM

Ok, to all the "just replace it" folks - I'm working on it - but I don't have the cash....so until that point, if I can fix it, I'm going to try.

And thanks for the ideas. I was thinking I didn't have enough fluid either. Several ppl have told me a bottle of Lucas tranny fix will do it. I'll keep fucking with it and let you know if I get anywhere.

One problem with checking the level, is that I've got what it came with, a bent oil dipstick jammed down in there, so I don't know where it's really supposed to be.

You mentioned a bad vacuum modulator. Could I be missing vacuum pressure from somewhere? The guy who I bought it from beat the piss out of it for years, so it's no surprise if it's gone, but there are *little* things all over the place that I find daily to fix, so if there's a hose or connection that could be bad and causing this, then I'll take a look at that.

I did add almost a whole quart of ATF yesterday and now it won't hit any of the gears, even reverse. So, I'm thinking it's fucked. But I've got to try everything, as the kids are going to get the money to eat before I get the money for the truck :-)

Thanks to you all.

Will

10/15/2010 11:48:33 AM