The two speed axle is in the truck. I still have to bolt it in place. I thought the axle straps for the u-bolts were the same, but the two speed has a larger diameter tube. So, I will have to clean up and paint the straps for the two speed.

Here you can see the difference in the straps.

The old axle


I also have to readjust the brakes, wheel bearings and make a new brake line for the axle itself. My drive shaft will work with a combination u-joint to adapt it to the larger yoke on the axle. Thanks, Nelson for the tip. Once I have the axle install finished to where the truck is driveable again, I will run the vacuum line and install the controls for the axle.
Thanks, Mark

 

Your truck is looking great, Mark! It looks like the lug pattern of the two speed rear is the same as the old rear. That two speed looks like a nice option for a better road speed.

 

Thanks! Howard. The backing plates, brakes, hubs, and axle shafts are off of the single speed axle that I took out. I had the brakes all done and painted on the other axle. Those parts are all interchangeable between the single speed and two speed axles. The axle shafts from the '51 two speed aren't threaded for the jack screws though, which I need to install my hub caps, so I'm using my '49 axles. The two speed won't gain me any more speed as I already had the same 5.83 gears in the single speed, but it will allow me to split shift to keep the RPMs in the power band of the diesel, at least that is my plan. You probably have 5.14 or 5.83 gears in your F4. A two speed would really make a difference in driveability if the truck had 6.66 gears.
Mark

 

Thanks for clarifying, Mark. So the two speed adds more options for the lower ranges but not higher speeds. That's good to know. Looking good!

 

I have the u-bolts and spring clips, as Ford calls them, back on the axle. I have to finish torqueing the u-bolts to 285-330 ft lbs. I cleaned up and installed the rest of the hood trim this afternoon. I also have the block machined to mount the shift cable for the two speed axle on the gear shift stick. Photos to follow.



Once I mount this permanently on the stick, I will probably use heat shrink tube to hold the cable in place. Before I mount it permanently I may heat and bend the stick over toward the passenger side a little. Right now, as it is, I can't get my knee between the **** and the steering wheel to put my foot on the brake when the transmission is in second gear. I may also modify my brake pedal rod to lower the pedal about an inch. If I do that, I will put a stop block on the pedal also to set the pedal height.

I am thinking about mount this badge somewhere on the back of the hood. I had it on the door next to the F4 emblem, but I think it looks better here. What do you all think?
Thanks, Mark

 

I'd put it under the F4 Emblem. But that is me.

 

That is where I first intended to put it, but it is too long. The fender seal covers part of it up.
Thanks, Mark

 

I worked on the truck some yesterday and today. I have the wheel bearings adjusted and axles back in, the wheels on and torqued to 475ft lbs, filled the axle with oil, made and installed the new brake lines, and installed the new bellows dust boot on the axle shift diaphragm. I couldn't find 90W gear oil locally, although 140W is available, so I used Mystic 85-140W oil that has a MT- 1, GL- 6 rating. With the MT- 1 rating, if I understand correctly, it should be yellow metal safe. Thanks to Stu sending me a copy of the Eaton axle service handbook, I was able to fill the axle with the proper amount of oil. Everything I have read said that the Eaton 1350 axle used 13 pints of oil. The Eaton manual said to fill thru the back cover 13 pints, which will just start to run out the hole. Then replace the fill plug and add one more pint thru the fill hole in the top of the differential. So, it actually takes 14 pints. I also drilled and tapped four 7/16" bolts to install the rear hubcaps. Here are the pics.




The new bellows on the shift diaphragm.

I still need to bleed the rear brakes and build and install the driveshaft. I was going to use a combination joint and just reuse my old driveshaft, but I couldn't find a combo joint locally. I did some digging in my parts stash and found I have enough parts to build a driveshaft to use the larger joints, so I will do that.
Thanks, Mark

 

Very nice Mark. I have a couple of questions. Where were you able to chase down a boot for the diaphragm linkage, and what did you use to torque the wheel nuts?

 

That's going to be such a fun truck to drive! It's a shame the fender gets in the way of the area below the F-4 emblem because it would be a great spot for it. The rear side of the hood should look good too though.

 

Bob, I bought a 3/4" drive 475 ft lb torque stick to torque the wheels. Here is a link for the bellows I used.
https://www.ebay.com/itm/Machinery-R...-/323119785082
It is too long, actually a little over twice as long as needed, so I cut it off and used a wire tie on the diaphragm end and an O-ring in the last groove of the bellows to secure it in the groove on the clevis. You can barely see the O-ring in the last groove in the pic below.


Thanks, Mark

 

Excellent. I have a new boot on the way. Thanks.
I assume you are aware that torque sticks only work with impact guns?

 

Your Welcome! Yes, I'm using it with my 3/4" impact. I decided to go the torque stick route because with my back issues I didn't want to be tugging on a wrench.
Mark

 

Mark,

Your 2-speed looks real nice! Have you had a chance to put it through its paces?

Nelson

 

Thanks, Nelson. I don't have the vacuum lines run yet, so the diaphragm has the axle locked on low range. I have moved it around the yard a little, it is definitely lower geared! I am going to try to get it in the shop tomorrow or Friday over my work pit, so I don't have to lay under it to run the lines and mount the vacuum tank. I also have a few little things to finish up underneath that I will try to do while I have it in the shop.
Mark