Ford CMP- Transfer case insulators
 

Good day,

I am revisiting this item as I have my spare tyre carrier off for repainting it and I have good access to the mounting bolts for the transfer case on my F15-A.

Many moons ago I made up some transfer case insulators from 4 mm insertion rubber. It has perished as can be seen in the photo. I have looked everywhere for the part in various publications but haven't found it. Only reference I have is in the Maintenance Manual, Ford calls them "insulators" Chevy manual calls them "spacers". Ford Special Pattern Vehicles booklet also mentions "insulators".

I got some new 8mm conveyor belting yesterday, the thinnest I could find, and thought I might use that as it is tougher than insertion rubber and has two layers of fabric instead of one as is used in insertion rubber.

The three trucks I had all had transfer cases removed at some time, so I never even had a rough sample as a guideline. All were bolted tightly to the frame with nothing between the case and frame. Some even used lock washers on the mounting bolts and were not wired as shown in the manuals.

Has anyone ever seen original insulators, and if so, what would be the thickness? I am hoping 8mm thick insulators would not cause any problem with transmission-transfer case jackshaft alignment. The change of angle would be minuscule unless I am missing something.

By the way the washers were not originally used there. Just some spare large enough shock absorber washers that I had at the time. Since then I have obtained round ones!

Good old rubber.......
 

Hi Jacques

We were always inspired by the similarity of the rubber washers to the side walls of original thick CMP sidewall tires...... I am not sure we ever did removed an "original" rubber washer but all our replacements were made of the 1/2 inch thick multiply old CMP tires .....and all have served us well.

Bob C

Ford CMP- Transfer case insulators
 

Hi Bob,

That's good to know. I don't think I will have any problem with 8mm thick conveyor belting then. The conveyor belt people offered me 15mm belting too. Maybe should grab some of that. The price is right- free, as they are strips cut off the sides of new conveyor belts to fit customers width requirements.

Thanks, for that information.

Cheers,

Ford CMP- transfer case isolators
 

Good day,

Finished the new isolators. They are 6mm (1/4") thick. I previously said they were 8mm thick, my mistake.

I was going to cut them square but as I had to use a hole saw for the bolt holes, I used a hole saw cut them out. Once I got the drill press speed right- slower, and a bit of silicon spray when cutting, the workshop stopped smelling like a dragstrip. I don't believe washers were used under the isolators based on a photo I just received but I put them there to spread the load over a bigger area.

I looked at the Design Record Canadian-developed military vehicles WW2, Vol 4, excerpt attached, when trying to find info on the isolators. Of interest, originally, they considered them for noise reduction but had concerns about misalignment. A change of thought during production perhaps?

Based on actual experience anything from no isolators to 1/2" thick isolators causes no problems with the alignment of the transmission and transfer case. Just the same, I have enough belting left over to cut out 4 more isolators if I want to increase the thickness to 1/2".

Hope this is of some interest.

Cheers,

This is great info, Jacques!

Now that I am aware of this of course I need to fit these to my F15A.

Quarter inch / half inch.......
 

Hi Jacques

Some cab 13 have coil springs on the front cab mount others have large crude rubber washers......... whether for vibration or flex one has to remember that riveted CMP frames are very flexible and will twist wildly over rough terrain.

The difference between 1/4 and 1/2 does not matter much as you will be aligning the shifting mechanism of the T case to match the frame twist. when I was road testing my C15a with a transplanted 2 speed t case I had to do a lot of fiddling to get the shifting rods of the T case just right..... at first everytime I drove over a steep road bump the t case would pop in neutral leaving me stranded and the gears locked in neutral... eventually got it right.

No matter what they ride hard......

Ford CMP- Shifter linkage transfer case
 

Hi Bob,

Interesting points you raised.

Yes, the cab on two rubber isolators up front, and an isolator and springs rear, would make for some movement between the shifter arm and the transfer case during twisting and bouncing along. Hopefully enough give on my single speed F15-A lever setup to avoid some of the problems you mentioned.

Here are some recent photos taken last weekend of a mate's transfer case isolators on a two speed F-60 transfer case. Possibly original but flogged a fair bit. They Could have 4 layers of fabric in them which is in keeping with tyre sidewall or heavy conveyor belting.

Cheers,

Rubber shortages.....
 

....may have driven them to officially use old tire sidewalls......after all they were available for the taking......

The two speed T case can be a nightmare of adjustment with delicate screw in adjustment on the rods...... the trick was to find the right spot and retesting until I found a sweet spot...... takes a while= to adjust the rods one turn...reassemble and retest....... to find out you went to far and now have to unscrew one turn and try it.... the two sseed is really great for crawling over obstacles......or real pulling like digging out my Massey tractor when sunk in the mud...

Bob,
Please don't try to use the complexity of adjusting your 2 speed T-case to try to convince the Ford owners of your Chev's superiority...
I'm almost certain that instead of the Chevrolet method of mounting the shift linkage to a bracket on the frame and the transfer case also being mounted to the frame (allowing relative movement as the frame twists), the Fords mounted the linkage and lever to a cast bracket mounted directly to the 2 speed transfer case which should have greatly reduced the chances of the lever and case getting out of alignment.

Reference diagram- Ford transfer case insulators
 

Surprise! The Australian Military Forces "Drivers Handbook for Ford"- 1945 shows the transfer case insulators. Only one publication out of 4 to actually show them. And on the F15-A transfer case too, same as mine.

Was beginning to think I was chasing a phantom part.

Cheers,