Looking at 1st deuce, how to tell if sprag works?

[Jinx]

Please excuse the noob question.

I'm going to look at a deuce for sale this Sunday. It has a sprag front differential, which I've read can be trouble prone. How can I tell if it's working properly? I assume there is no lever to engage 6x6 mode like there is with the air shift trucks. It' just always in 6x6 mode. Is this correct?

When testing 4x4 truck you can engage 4 wheel drive and drive the truck in circles. It's very easy to tell if 4x4 works or not because the truck handles differently. The front tires try to pull the direction you are turning, while the rear tires try to push forward. Would a similar approach work when testing a deuce?

 

[JohnnyReb]

Owned 2 sprag trucks and never was happy with them. Even if the system is working today, it may not work tomorrow.

Some guys like the sprag because it is more original to the trucks. If you are seriously looking for offroad use, I recommend that you stick with the air shift.

Just my 2 cents....

 

[doghead]

If the price is right, you can always change it out and have an air shift tcase.

 

[dm22630]

I HATE sprag. With my airshift trucks I can back up wet hills, and the sprag trucks wont back up them when they are dry. I can not tell you how much of a difference it is....

Sprag sucks.....only get one if you are getting a deal you cant refuse.

 

[JasonS]

The sprag is in the transfer case. Keep in mind that the sprag clutch relies on friction to engage. This friction is also continually wearing out the sprag segments. After decades of use, it is not surprising that most are not working optimally. The forward direction is the one that is always worn out. Reverse ALWAYS worked for me. This suggests that a sprag transfer case with good sprag clutches would work fine.

 

[Jinx]

Thanks for the info guys. I'm going to look at the truck this Sunday. The asking price is $2K. If I like it, I'll offer less of course. There are some other leads I've gotten here on the site as well and don't want to be too hasty in my purchase.

Maybe it would make more sense to save up a bit for a better truck.

 

[bbf]

have a deuce and my 5 ton have had no problems with them

 

[Barrman]

My '52 Gasser has the sprag and it works great. I like it. Or, at least I did until I got the air shift multifuel. No more worries about creeping backward when starting on an incline, no more worries about coasting to a stop and no more pulling the front hubs to flat tow.

To answer you question about testing a sprag. Find something solid to push or pull against with soft soil around it. Get the rear wheels spinning in low range and see if the fronts start to spin as well. There is an adjustment that can be done. However, you really can't tell during a test drive and quick crawl under the truck if the clutches or bad or just out of adjustment. Use the going price of an airshift, $1000 or so, as a barganing tool.

 

[Jinx]

Great advice Barrman. Thank you very much.

 

[rivired]

hey i noticed your near seattle..might wanna take a look at the tenino trucks..i jsut got one and wrote about the others..

http://www.steelsoldiers.com/showthread.php?t=30977

 

[Irv]

sprag is in all of them, including airshift

The front end of early mil deuces were engaged by a rod coming out of the top of the transmission. When you were in forward direction, the rod would set the front sprag (there are front and back sprags in that one assembly) to engage if slippage occurred. If you were in reverse, then the rod commanded the reverse sprag to engage if there was slippage. This is not the same as simply engaging the front end. The sprag, once engaged, will only transfer torque if there is a difference in the rotation of the front and rear drivelines. The airshift mod did not affect the sprag. It only replaced the control rod. Now, valves in the top of the transmission route air to an air solenoid on the transfer case to engage the front or rear sprag, again looking for slippage. Many times, a failing sprag is just a matter of adjusting the length of that control rod with the adjusting section provided. To see if sprags are working, jack up one front corner of the truck. Put tranny in granny. The wheel will rotate only one direction. Put tranny in reverse and repeat. Wheel should only rotate the opposite way, now. If it free-wheels, the sprag is either bad or the control rod needs adjusting. Bottom line: Converting to air-shift does not take the sprag out of the equation. It only affects how you communicate with it.

 

[JasonS]

The front end of early mil deuces were engaged by a rod coming out of the top of the transmission. When you were in forward direction, the rod would set the front sprag (there are front and back sprags in that one assembly) to engage if slippage occurred. If you were in reverse, then the rod commanded the reverse sprag to engage if there was slippage. This is not the same as simply engaging the front end. The sprag, once engaged, will only transfer torque if there is a difference in the rotation of the front and rear drivelines. The airshift mod did not affect the sprag. It only replaced the control rod. Now, valves in the top of the transmission route air to an air solenoid on the transfer case to engage the front or rear sprag, again looking for slippage. Many times, a failing sprag is just a matter of adjusting the length of that control rod with the adjusting section provided. To see if sprags are working, jack up one front corner of the truck. Put tranny in granny. The wheel will rotate only one direction. Put tranny in reverse and repeat. Wheel should only rotate the opposite way, now. If it free-wheels, the sprag is either bad or the control rod needs adjusting. Bottom line: Converting to air-shift does not take the sprag out of the equation. It only affects how you communicate with it.

It is not sufficient to jack up one wheel and give it a spin. Under load, a marginal sprag will still slip (in my experience). While there may be a kit to convert a sprag to an "air engagement" the air shift transfer case being discussed does not have a sprag.

 

[Jinx]

hey i noticed your near seattle..might wanna take a look at the tenino trucks..i jsut got one and wrote about the others..

http://www.steelsoldiers.com/showthread.php?t=30977

I gave the guy in Tenino a call this morning. He didn't answer his cell. I left my number. I f he calls back within an hour I can look at his trucks today. If he doesn't, I couldn't look at them until next Sunday. (I only get one day off a week)

 

[gringeltaube]

......................................................... the air shift transfer case being discussed does not have a sprag.

Ahhh....to bad you said this! I'm really confused now and hoping to have Irv give us a good lesson explaining where exactly the sprags were to find in the T-136-27 front output section. Or maybe they had to place them somewhere inside the main housing????? Anyways they sure are well hidden........

Is there a manual or so.....?

G.

 

[Barrman]

The 5 ton transfer case is air actuated as far as telling the Sprag which direction the truck is going. More specifically, the air is only used for reverse. At least in the 5 tons I have been around you can only hear it thunk-Hiissss when you put it in reverse.

The M35 air shift transfer case can be best described as working like a regular truck t-case. You flip the switch on the dash and the front axle is mechanically linked to the rear no matter which direction you are going.

 

[Jinx]

I gave the guy in Tenino a call this morning. He didn't answer his cell. I left my number. I f he calls back within an hour I can look at his trucks today. If he doesn't, I couldn't look at them until next Sunday. (I only get one day off a week)

Update:

He called back and I checked out his trucks. Really like the one with the "D" motor. It drives great, minus the soft brakes and nonfunctional speedometer. Unfortunately the guy wouldn't even entertain offers on the truck and I didn't have enough to pay full price.