Hey half track guys - Steel Soldiers::Military Vehicles Supersite

Blythewoodjoe · 07-25-2009, 15:45

Quick question. Are the two axles in my M15A1 half track geared the same. In other words does the transfer case turn the rear axle for the tracks once for every turn for the front, wheeled axle. I have no drive train and was thinking about putting in something to make the front axle turn. I have lots of deuce transfer cases and modern engines.

Thanks,
Joe

NDT · 07-25-2009, 16:01

Nope not the same ratio. Are you having trouble finding a 160AX engine and transmission/transfer?

vj · 07-25-2009, 16:15

joe, you might be going the wrong way on this, i guess you got the tracks and boogies,, i would try to find the correct set up, i know you want to use what you got, , but if you got the bed and a lot of the h.t. , i would try to go the right way. post a picture of it, i can tell you more. i got 4 halftrack, and i work on them, wendell

Blythewoodjoe · 07-26-2009, 00:48

Well here's the story. I may never have the money to put a running stock engine and drive train in this half track. I plan to put an engine and trans in it and either hook it directly to the real axle or install a transfer case and possibly connect the front axle. If the axles are completely different gearing I will not even think about the transfer case.

I plan to BOLT everything into the half track in hopes that one day I can find or build a running stock engine and all the stuff needed to put it back to original. In the mean time I don't plan to let it sit in the yard rusting. I want to have it move on it's own power and I have several drive trains available at no cost to install. I know some folks find this offensive but it takes money to play with these things right and until my house is paid for I can't justify spending thousands of dollars on a stock engine. But I do want to see the old rust bucket move around the yard. I have tons of scrap trucks, a welder and rods.

So anyway, I assume most all wheel drive trucks have the same gears in the front and rear, but does a half track? And if not does anyone know what the ratio between the front and rear out puts on the transfer are.

Thanks,
Joe

rivired · 07-26-2009, 01:24

That would be a hard find..i never though about a T case with diff ratio outputs!..

Great to see u wanna get it movin tho and not rustin

Good Luck!

m.walker · 07-26-2009, 09:18

I would hazard to guess that maybe the t-case has the same outputs just the ratios are different because of a tire on the front and the wheel driving the tracks are different sizes . Put marks on the yokes to the drives , roll it one full turn of the front tire , count the revolutions of each yoke , if they're the same run any combo you like . Just put something in small enough that you don't have to cut out anything . I'd put in something small with an auto just to putt around in . In this day and age money is scarce for alot of us ! Let us know how it turns out .

halftrack · 07-26-2009, 09:37

You would be wasting your time and money. Just save and get the right setup from the get go or you will never be satisfied with the project.

lacoda56 · 07-26-2009, 09:40

The diameter of the drive sproket is quite a bit smaller than the dia. of the front tire, so I would think the t-case ratio would be too far off for any other than stock replacement. If you're not planning any serious mud runs or hill climbs, I don't think track drive only would be a problem. I know the purists will be on a rant, but it's yours and you should be able to do what you want. Way better than on a scrap ship to china!
By the way, the t-case and trans are a single unit. If yours works out, I have a junk M3 out back that I might try something similar with. Too many projects, not enough time!

spudwacker · 10-09-2009, 23:50

Just an observation from a farm boy and an off roader. Being that the drive sprocket is a different diameter than the front tire (as lacoda56 has stated) the diffs would have to have a different ratio to get the front tire and the drive sprocket to turn at the same road speed. The drive sprocket doesn't care if it is on a 20ft long track or a 100ft long track, all it cares about it how many revolutions the outside edge of the drive sprocket has to move for every revolution of the drive shaft.

Our AG tractors that have mechanical 4wd have one ratio for the front diff and another for the rear diff, the little tire in the front has to make more revolutions per distance traveled than the big tire in back; but the transfercase has the same ratio (otherwise expensive parts go boom) and that is why you have different ratios on the 2 diffs. So if you change tire size on the front of the halftrack, you have to figure out what the new ratio will be to maintian the same road speed of the drive sprocket/front tire.
I hope this helps.

ida34 · 10-10-2009, 00:33

I don't know half tracks but I would doubt the transfer case would be the mechanism to compensate for the different diameters of the drive sprocket and front tire. I think it much more likely that the both outputs of the transfer case both move at the same speed when the case is locked into all wheel drive. It would have been much easier to have different ratios in the front and rear diffs to make up the difference. If this is the case then you would be able to use a none original transfer case.