Cletrac Tractor Discussion => Military Cletracs => Topic started by: Gordon_M on June 08, 2011, 11:41:35 AM

Title: Not your average military Cletrac
Post by: Gordon_M on June 08, 2011, 11:41:35 AM


Thanks to Matt Rimmer for pointing me at this site.  My T-36 Iron Fireman is supposed to have a Cletrac model MG differential, but the control levers and ratchets don't look anything like Matt's.

Anyone here ever run across another T-36 or know anything about them?

Gordon McMillan

central Scotland

Title: Re: Not your average military Cletrac
Post by: Ol Paint on June 17, 2011, 06:37:42 PM
The only thing I know about them is what was published in Fred Crimson's U.S. Military Tracked Vehicles.  See scans from pages 224 & 225, below.  Unfortunately, no interior views.




Title: Re: Not your average military Cletrac - another one
Post by: Gordon_M on July 10, 2011, 06:05:53 AM
It turns out that another T-36 with the Cletrac diff is in Polson, Montana, at Gil Mangel's Miracle of America Museum.

Gil is stuck with the restoration of it, as someone took the drive ends off the differential and they got lost.  I still think that the drive outpus from the T-36 diff are pretty much the same as the MG1 and MG2 units, so anyone in the US with a broken differential and a pair of drive ends they are never going to use?


That image is the drive ends on my T-36.  The Parts List does say it is an MG-type differential, so I'm hoping someone here can help.


Title: Re: Not your average military Cletrac
Post by: wanderingwillys on August 29, 2011, 10:14:01 PM
What pieces are they missing? The actual drive flanges or the extension housing - I may be able to help depending on the condition of mine when I pull it down - one of my MG-1's has a cracked final drive spacer block and I am likely going to get a parts vehicle to replace the damaged parts - anything from the cracked unit may be available based on inspection results


Title: Looking for info
Post by: Gordon_M on August 19, 2012, 07:35:19 AM
Thanks Matt, I don't think standard bits would help - unless they happen to look like that image above.  I think Gil is short of those conical housings and the driveshaft / sprockets.

On another point, I've pulled the cab and drivers compartment off mine to reveal the differential  I can see a fill / level elbow right front and what could be a level plug slightly lower down at the rear;


There are plugs at the same locations and heights on the other side, without the fill elbow;


... and I think the plug at the top left is just an end cap covering the end of the operating lever shaft.

Since all the remaining T-36s that have speedometers seem to show less than 200 miles, I'm assuming the diff will be fine and just need topped up.  On the assumption that the diff is internally the same as the MG military unit, how much of what lube do I put in the fill elbow?  Do I take a rear plug out and just fill it with gear oil at the front elbow till it comes out the, back, then stick the plug back in?

I have no military manual info for the MG differential, and dont want to do something extra-stupid like put oil in a port that is access for brake band adjustment, or whatever.


Title: Re: Not your average military Cletrac
Post by: Blake Malkamaki on August 19, 2012, 12:37:23 PM
As far as I know, all the Cletrac Controlled Differential Steering units use 50 wt non-detergent motor oil. Some people have used a gear oil of similar weight and composition; just don't use hypoid type oils or oils with extreme pressure additives. Whatever you use, you don't want anything that will increase the lubricity over motor oil, nor anything that will harm brass or bronze bushings.


Title: Re: Not your average military Cletrac
Post by: Gordon_M on August 21, 2012, 11:58:06 AM
Thanks Blake, always good to know.  I can find something locally that will do.

So, just pour it in the fill elbow then?  Take out the rear plug for a level, or just use the fill elbow?

Thanks again.


Title: Re: Not your average military Cletrac
Post by: Blake Malkamaki on August 21, 2012, 06:53:53 PM
I don't know anything about the machine you have, so I can't speak specifically about it. However, I've attached a cutaway of a Cletrac model A crawler, where I shaded in blue the levels of oil in the transmission, the steering housing and the final drives. As you can see, you don't want the steering components completely submerged in oil. I can't tell by  your pictures where the oil levels would be on yours, but you may want to search for another level plug somewhere.


On the Cletrac tractor the oil is constantly being pumped from the final drives up to the transmission, where it runs over a series of dams and flows down to the next chamber, eventually getting back to the final drives.


Title: Re: Not your average military Cletrac
Post by: Gordon_M on September 01, 2012, 03:26:48 AM
Thanks Blake, I'll use caution then, probably leave it as it is till I have to use it.

I reckon I'm more liable to damage it by over filling that running it low, since the average mileage on the other three I've found is under 200 miles from new.

Got a Parts List, but no manual, unfortunately.


Title: Re: Not your average military Cletrac
Post by: Lowspeedlife on January 29, 2014, 08:29:45 PM

Hi Gordon, this is a pic of an M2 high speed crawler differential. This one is in Ohio. I have another pic that looks like most of the suspension & the tracks are there too!