I have a 1967 F-100 short bed. The truck has a 300 inline 6 that is stock other than a rebuild, originally a 3 speed on the column and 3.70 gears. I drive this truck a lot to save miles on my newer vehicle. I have a 70 mile round trip commute that I use this truck for...gas mileage was decent with the three speed but fuel was still getting costly. On average I would average 16.4 MPG. My crazy goal was to hit 20 MPG....So....

Recently I swapped in a T-170 RUG 4-speed with overdrive. The swap went smoothly with my only issue being that the RUG transmission was 6" longer than my original 3-speed and a very sloppy shifter. I got a shorter driveshaft to accommodate the difference in length and am currently researching how to rebuild the shifter to take out some of the slop.

I replaced the clutch roughly 5K miles before swapping the transmissions so I didn't replace the clutch again as it still worked flawlessly with smooth operation.

The issue that I am having and that I am slightly stumped on is a clutch issue. Before the swap, my clutch effort was minimal and extremely smooth.

Now, when you first start the truck and drive it for a couple of miles the clutch feels fine and as it previously did before the transmission swap. As you drive the truck longer and everything gets to operating temperature the clutch pedal operation goes south. The pedal effort increases drastically, and no longer presses/depresses smoothly. The pedal is slightly jerky. Actual clutch operation as far as engaging to apply power and move the truck still operates fine other than it is harder to let it out smooth as the pedal is grabby feeling. The pedal is grabby and hard to push whether the motor is running or not, after it warms up.

I am stumped on this one and have run out of ideas. Clutch pedal is adjusted to spec with approximately 1.5" of free travel.

I have attached a photo of the truck in question for inspiration!

Any and all help is appreciated to help me get this clutch back to being a breeze to drive instead of a hassle!

 

This is a puzzler.
Start by having wifey pump the pedal while you look at the linkage, above and below. Broken fork? Messed up bushings under the dash?
Let us know what you see.

 

I take it it has a hydraulic clutch then with that transmission?

 

That's was my thought too. If it is hydraulic, then the heat maybe causing some of your problems. Do the checks mentioned above. Then check the hydraulic system, ie:hoses, fluid quality and level, connections snug.

 

Some of the early 3sp with over drive, some call it a 4sp whete 4th was OD, used linkage like the truck did stock.
Now let's say he is using everything from his truck with the new OD trany.
I would get a throw out bearing for both his truck and what should be used with that OD trany then measure both.
My guess is the old one he is using has a too small of an I.D. that should slide on the trany snout.
Because it is too small the snout heats up and expands and now you have binding.
If you can might want to measure the snouts of both tranys too.
Dave - - - -

 

Some of the early 3sp with over drive, some call it a 4sp where 4th was OD, used linkage like the truck did stock.
Now let's say he is using everything from his truck with the new OD trany.
I would get a throw out bearing for both his truck and what should be used with that OD trany then measure both.
My guess is the old one he is using has a too small of an I.D. that should slide on the trany snout.
Because it is too small the snout heats up and expands and now you have binding.
If you can might want to measure the snouts of both tranys too.
Dave - - - -

 

Alum bearing retainer on that transmissions? Sounds like the TOB is getting snug with heat. Did you lubricate that surface before installing new transmission?

 

The transmission is a toploader style with overdrive being in 4th so all original clutch linkage was used.

Looks like I will have to pull the transmission and measure the shaft and ensure I am using the correct throwout bearing.

Will also have to find some part numbers and see if the two transmissions call for different bearings.

 

So it's a SROD 4spd. So it is still a mechanical clutch linkage. The bearing retainer should be the same as your old 3 spd. Many of the newer transmission retainers are aluminum(like the T5) and I was wondering if it was swelling with heat and making the TOB get stiff. Though heat is the issue, so it may still be just tight when cool and too tight when warm.

 

I ended up pulling the transmission back far enough to remove the bearing retainer shaft. Polished it up and made sure that the TO bearing and it were matching dimensions. Got it all back together and it is silky smooth now!

I would recommend this 3-speed with OD swap to anyone! Much more enjoyable to drive and it was a very noninvasive and affordable swap. The hardest part was scrounging the parts together.

Thanks for all of the help!

 

ALL 1978/83 F100/150 RUG SR-OD single rail 4 speed overdrive used mechanical clutch linkage.

1984/87 F150/Bronco RTS TS-OD top shift 4 speed overdrive used a hydraulic clutch.

Hydraulic clutch introduced in 1983 F250/350 460 & 6.9L Diesel. Everything else got it in 1984.

RUG SR-OD also used in misc 1978/83 Passenger Cars & 1978/87 E100/250.

What did the RUG SR-OD come from? The Econoline uses a totally different shift linkage!

 

Good to hear you got it working better.
Could you see where it may have been rubbing?
Dave - - - -

 

There was a slight wear mark and the shaft as well as some pitting. I don't know why I overlooked cleaning up that shaft before installing it.

 

Good to hear you got it working well. Those transmission work okay, and the added OD is nice. Not much of a performance transmission, they are a bit weak in the knees, but for cruising they are fine.