I changed the transmission filter on my 1968 F-100 (it has a 1971 302 and a 19?? C4 in it) today and after getting it all back together I started it and let it idle for about 15 minutes. It was running fine, but when I put it in gear, the transmission was surging and jumping forward. I realized that the transmission fluid level was low, so I added more until I had the correct amount. It ran fine after that, so I took it out on the street. The engine was still running fine, but it seemed like it was slipping just a little on acceleration. The more I drove it, the more it slipped right off the line, but it always seemed to run decent after I was up to about 15mph. Eventually, it got to the point where it wouldnt go anywhere in any of the forward gears--the motor would just rev way up when I gave it gas, but the car would go nowhere. For a while it wouldnt even move in reverse, but eventually I was able to get it to move in reverse and back in all the way back into the garage.

The tranny seemed to run fine before I changed the filter, and I dont remember breaking anything in the process...

I used type FA transmission fluid, which I understood to be comparable to type F.


I didnt drain the fluid in the torque converter. All-in-all, I refilled 6 quarts into the tranny. When hot and running, the dipstick reads full.

When I took off the transmission filter, a spring about an inch long and about 3/8 inch in diameter fell out, along with a small metal piece that looked like a screw without threads (by this I mean a slender rod with a larger "head" on it). The metal piece fit perfectly inside the spring. The only logical place I saw where the spring and metal piece could go was in a hole under the tranny filter (the only hole I could find under the tranny pan) such that it rested on and pressed down against the tranny filter and provided some sort of "down pressure"...? Perhaps there was a metal ball that rode on top of that rod and spring, that plopped into the drainpan unnoticed... If anyone recognizes this spring and rod (and perhaps ball bearing) combo I am talking about, do you know the orientation (head into the tranny, head resting against the filter, etc. ) ?

I have no idea when the filter was last changed, but I imagine it was a long time ago, because the gold screen on the bottom of the filter was completely missing...

Any suggestions?

 

The parts you found are vital to the transmission.
They must be installed like so.

Small valve first then the spring.
The filter holds it all in place.

 

Does the valve go in head or tail first? Please describe like you are teaching a 3 year old to tie his shoes...

 

The flat portion of the valve goes in first. The spring rides on the stem.
The filter holds the whole sheebang in place.

 

Many thanks. Will swim in luxurious red oil again tonight and keep you updated.

 

I pulled the transmission pan and filter and reinstalled the valve and spring as suggested. They were in backwards, but putting them in correctly did nothing to improve the problem. The truck still will not go anywhere in any of the forward gears, but it runs just fine in reverse.

After pulling the pan, I added 5 quarts of fluid as suggested in the shop manual, but after warming up, the dipstick still reads like it is over filled. I wonder if the fluid is not circulating through the transmission properly...

Any suggestions?

 

Depending on how far the vehicle was driven you could have toasted the transmission.