Trackmaster bulldozer Transmission rebuild 02 – restoration, cleaning, fabrication

The transmission mechanicals were surprisingly not that badly damaged. It did take an enormous amount of elbow grease to clean all of the grimy oily emulsified yuck off of and out of everything. After cleaning, inspection, polishing, identification of replacement components and so on took place.

Parts laid out from the transmission rebuild. I take a lot of photos so I can reassemble everything. It’s a good way to take anything apart, take all the photos you can.

A bit about what I know about this transmission after taking it apart and studying it. I could find ZERO information online, and I write this stuff up in hopes that it helps someone in the future.

The 3 speed transmission is a symetrical standard splined shaft transmission using sliding standard spur gears. There are two shift forks, and two movable sliding gears. One gear only has one position, the other has two locations. It is a very simple and robust transmission design, with nothing broken and no unbearable wear or damage despite it’s poor condition when I took ownership.

Shafts, splines, sprockets, snap rings are all standard ANSI and SAE. Only the bearings are metric 6000 series items. The three gear reductions of the tranmision are 1.5:1, 4.5:1, and 18.5:1. These are counted manually by turning the input shaft and counting after rebuild and can have a bit of innaccuracy.

The main output shaft is 13/16″ for the 16 tooth sprocket for #60 chain. The bearing on the main shaft is a standard 6305 with bearing dimensions 25x62x17mm Deep Groove Ball Bearing. All of the other bearings, 7 in total, are the same and are 6203 Bearings with dimensions 17x40x12mm. There is one oil seal on the output shaft. This oil seal is an old out of production part: Chicago Rawhide Oil Seal 8774. A modern replacement oil seal I found was a SKF 8796 LDS & Small Bore Seal, R Lip Code, CRW1 Style, Inch, 0.875″ Shaft Diameter, 1.624″ Bore Diameter, 0.25″ Width . I ordered this, and then found an original NOS part on Ebay and ordered that as well. Both have the same dimensions and basic design.

A quick trick for pulling Blind ball bearings

It often happens as you are working on rebuilding or restoring some old iron, machine tool, etc that you come across a blind bearing in some machined pocket. These can be a real bear to remove, especially if as in the case of my 70’s era Trackmaster bulldozer it’s a nasty mess in need of restoration. You can see the blind bearing in the top middle of the photo below.

Trackmaster dozer transmission housing by d-Fab Engineering a devision of Fruehauf Corp Route 202, Montgomberyville, Pennsylvania USA

I looked for a puller tool, they make them but even cheap ones are still a bit pricey for a single pull. This bearing, like all of the others was trashed, so I knew I wasn’t going to be reusing it, and as such I went with the tride and true method. I’ll share with photos below the details of one of the best ways to get a stuck bearing out.

Blind bearing removal Tip Step 1: make a threaded bushing for the ID of the bearing, or use a nut that fits the opening well enough.
Blind bearing removal Tip Step 2: insert your a threaded bushing and weld it carefully to the inner race, you can mig or tig depending on what you have.
blind bearing removal trick step 4: screw in your bolt, and press out the bearing from the blind pocket. Even if it was stuck before, often the heat from welding and cooling will allow it to press right out. Never discount the force generated from an inclined plane wrapped around a cylindrical axis in any pressing operation. *Wear eye protection. Every now and again the bearing explodes into shards of sharp metal that fly everywhere.
The inside of the 3 speed bulldozer transmission has cleaned up relatively well. A bit more work cleaning and it will be ready for the reassmbly.

Summing up my favorite blind bearing removol trick in steps:

  1. Make a threaded bushing for the ID of the bearing, or use a nut that fits close enough.
  2. Place in or on the bearing with the threaded hole centered as best you can.
  3. Weld in place, and let everything cool fully. (you don’t have to go nuts, three good spot welds spaced are usually enough)
  4. After it cools, thread in a good quality bolt with some crease or oil on the threads
  5. Start turning and let the screw press out your blind bearing.

This of course requires a welder, but many of the tools I looked at cost as much as a cheap HF welder. Go buy the welder, you will be happy you purchased it rather than a fancy one time use blind bearing removal tool.

Trackmaster bulldozer Transmission rebuild 01 – Dissasembly and cleaning

Take a good look at the photo below, Let it all soak in… Yes this is the state of the transmission when I took it apart. Makes you want to cry a wee little bit huh? But this worked, albiet loudly, it still ran even in this state.

3 speed bulldozer transmission on Trackmaster crawler loader dozer
Interior of the three speed transmission on a Trackmaster bulldozer

Yes and that’s not the worst part of this whole dissassembly process. In the imortal words of the late great Billy Mays, “but wait there’s more!”

Broken Shift fork on a Dfab engineering Trackmaster crawler dozer loader
Broken shift fork Trackmaster 3 speed bulldozer tranmission

The only thing actually broken or wrong, outside of filthy, nasty yuck and a blown up bearing is that one of the shift forks is broken and gone. I’ll have to make a replacement. Thankfully the transmission is a symetrical design and I can use the existing one to aid in making the replacement. There are no parts for these lil dozers, so I’ll have to cast or machine my own new shift fork.

A bit about what I know about this transmission after taking it apart and studying it. The design is a three speed standard splined shaft transmission using sliding standard spur gears. A very simple and robust design, with nothing broken and no unbearable wear or damage despite it’s condition. Shafts, splines, sprockets, snap rings are all SAE. Only the bearings are metric. The three reductions of the tranmision are 1.5:1, 4.5:1, and 18.5:1. These are counted manually by turning the input shaft and counting after rebuild.

The main output shaft is 13/16″ for the sprocket. The bearing on the main shaft is a standard 6305 with bearing dimensions 25x62x17mm Deep Groove Ball Bearing. All of the other bearings are the same and are 6203 Bearings with dimensions 17x40x12mm. There is one oil seal on the output shaft it is an old out of production part Chicago Rawhide Oil Seal 8774, but a modern replacement exists if you can’t find the original. The modern replacement oil seal I found was a SKF 8796 LDS & Small Bore Seal, R Lip Code, CRW1 Style, Inch, 0.875″ Shaft Diameter, 1.624″ Bore Diameter, 0.25″ Width . I ordered this, and then found an original NOS part on Ebay and ordered that as well. they both have the same dimensions and basic design.

destroyed bearing in 3 speed transmission input shaft
A destroyed bearing on the input shaft of a 3 speed dozer transmission

I’m going to just share the rest of the photos as a Gallery of the dissassembly of the 3 speed transmission in my Trackmaster dozer. Mine is a later model Trackmaster, with the hydraulic motor rather than a direct drive off of the motor. You are welcome to click through and look at them all. Dissassembly was relatively easy, with nothing being super siezed in place or broken other than the shift fork.

In the next post I’ll show some reassembly photos and talk a bit about the trick used to pull a blind bearing, cleaning advice for this kind of filth, and more.

If someone stumbles across this page with any information about these Dfab Engineering Trackmaster Dozers Crawlers, I’d love to know more. I’d be happy to host manuals and or parts catalogs here on my blog if you have them and are willing to share them with me. Please leave me a comment or email me at my website name on Gmail (no dot com there). I don’t check often, but I eventually will get back to you to host the information. Thanks!

Dfab Bulldozer Restoration PArt 5: Transmission and Hydraulic motor

#60 chain drive off of the 3 speed transmission on my Dfab Engineering Trackmaster Dozer

The first thing I wanted to do, was work on the transmission. Now from these photos you can see pretty clearly that there is a lot of grime, grease and gunk in the belly of this beast. I started by removing with steel scrapers as much of this as I could possibly remove. I took almost 4 gallons in 1 quart containers out by scraper. It was nasty oily gunk mixed with mud and leaves.

yes, nasty cigarette butts in the gunk that is several inches deep on tiny dozer.

Another angle of the transmission, and more of the nasty

close up of the transmission. Notice the top isn’t sealed/closed.

Now part of this restoration project was knowing that the transmission was broken. It’s stuck in it’s mid gear (didn’t know which gear it was at the time) which provides roughly 4.5:1 input: output reduction. The other two speeds are about 1.5:1, and 18.5:1. The low gear in this transmission at 18:5:1 must be feircely slow, because the middle gear is not fast. Anyways, Note the top isn’t attached, and seeing the condition of everything else I feared this would be beyond salvage.

there are three connections to the hydraulic motor, two -10 SAE male JIC and one -4 male JIC (case drain I believe), along with 4 bolts in sliding slots (to allow tensioning of the chain)

Removal of the transmission required some funky bending of my arm to get at all of the nuts. There are 4 all metal lock nuts used to hold down the transmission. The bolts are welded to steel flat (will add a photo eventually) and slide in slots for tensioning of the chain. There was likely a chain guard at some point, there are spots that look like welded steel taps broke off in the correct locations for a chain guard. Additionally there are three connections to the hydraulic motor, two -10 SAE male JIC and one -4 male JIC (case drain I believe).

After loosening the transmission you can pull the chain off. I piled mine over on the rear drive assembly.
While this is heavy, it’s not impossible to manage. I lifted it out by hand, I’d guess it weighs in with the motor attached at 150 lbs

The transmission lifts out relatively easily after disconnecting it from the chasis and hydraulic systems. I used some hydraulic JIC caps and plugs I ordered as a kit to close off the system on the tractor side. This will ensure it doesn’t get any contamination in the fluid causing wear or damage in the future.

In the main shop, ready for some serious TLC

The removed hydraulic motor and transmission assembly. In the next post I’ll show photos of the dissassembly and problems discovered on this part of the Trackmaster crawler.

If someone stumbles across this page with any information about these Dfab Engineering Trackmaster Dozers Crawlers, I’d love to know more. I’d be happy to host manuals and or parts catalogs here on my blog if you have them and are willing to share them with me. Please leave me a comment or email me at my website name on Gmail (no dot com there). I don’t check often, but I eventually will get back to you to host the information. Thanks!