Front Axle not engaging?

[Strategic Tactical]

Alright, I have searched in here for a couple of days and can't find this. My M35A2 does NOT have teh front axle switch on the bottom of the dash that you flip to engage it. I don't know what its called but want to find one and get it installed. What is the part called so I can begin the search?

 

[rebelqwes87]

You also have to have an air shift tcase for that to work. From what you are saying you have the sprag tcase.

 

[Strategic Tactical]

So which one is better to have?

 

[fsearls92]

They both work just fine. Both of my trucks had sprags in them, and I would get alot of wheel hop in the deep sand from it engaging and disengaging. So I switched both of them out to airshifts and they work alot better for my uses. Also it is easier to turn now with the airshift, since in 1st and reverse the sprag is always engaged in 6x6.

 

[JasonS]

since in 1st and reverse the sprag is always engaged in 6x6.

It is in 6x6 in all gears.

 

[fsearls92]

Not so, it is only in 6x6 in 1st and reverse and its locked in. The other gears, the rear tires have to slip 20% for the sprag to engage.

 

[KsM715]

Not so, it is only in 6x6 in 1st and reverse and its locked in. The other gears, the rear tires have to slip 20% for the sprag to engage.

Are you sure about that?
The deuce sprag case is not air opperated like the 5ton. The sprag case has no way of knowing what gear the trans is in in a deuce.

For the OP. If you want the air shift front axle you need an airshift t-case and the switch and assoc. airlines plumbed in.

There is an adjustment proceedure for the sprag t-case. With proper maint the sprag case works just fine.

 

[gimpyrobb]

I didn't think it was locked in, in any gear.
The airshift is nice, but you have to remember to turn it on. The sprag will engage when the rears slip automatically. The thing is, it needs to be adjusted right AND they can wear out.

 

[Reckless]

In my five ton you can hear the transfer case "air shift" putting the truck in first and reverse, but does not happen in any other gear unless it slips like fsearls said.

 

[fsearls92]

I am positive about how the sprag works, it has been explained to me in detail many times. The sprag is a good transfer case, but for my likings I was very happy switching both of my trucks to an airshift.

 

[gimpyrobb]

In my five ton you can hear the transfer case "air shift" putting the truck in first and reverse, but does not happen in any other gear unless it slips like fsearls said.

That is just selecting the forward or reverse sprag. There is 2 different ones in the Tcase. That is why you are told not to drift backward in a forward gear and don't drift forward in reverse.

 

[fsearls92]

There is a rod on the transmission that when you shift into reverse or first it pushes into the transfer case and engages 6x6. You can definitely tell that is in 6x6 in these gears.

 

[gimpyrobb]

My bad.

 

[JasonS]

There is a rod on the transmission that when you shift into reverse or first it pushes into the transfer case and engages 6x6. You can definitely tell that is in 6x6 in these gears.

It is in 6x6 in ALL gears. Read up on the operation of this transfer case or jack up a front tire and try it out. The transmission linkage only switches from the forward sprag to the reverse sprag. The forward sprag is engaged by default. This has been beat to death in many other threads. Read up.

 

[Tow4]

I didn't think it was locked in, in any gear.

It's hard to tell the transfer case is locked when the truck is on it's side.

 

[fsearls92]

Yeah, I have read it plenty of times and as I stated is how it works. It is very evident when in deep sand and you stick your head out the window you can tell if its going or not. Mud works just fine as well to be able to see how it works.

 

[JasonS]

Not so, it is only in 6x6 in 1st and reverse and its locked in. The other gears, the rear tires have to slip 20% for the sprag to engage.

You are wrong. It is not "locked in" in any gear. Read section 86 in TM9-1819B which describes how the single sprag and dual sprag work.

 

[searls84]

In my five ton you can hear the transfer case "air shift" putting the truck in first and reverse, but does not happen in any other gear unless it slips like fsearls said.

Absolutely correct! For a deuce the shift rail for first and reverse extends out the back of the transmission, that connects to the Tcase (sprag only) which then moves the shift fork for the overriding clutches to engage either the forward sprag or the reverse sprag. A five ton is air actuated vs linkage for a deuce.

For the OP, your title says front axle is not engaging, but the post reads as though you are concerned about having a switch... What's the actual problem? No 6x6? Or are you wanting know what transfer case you have?

 

[KsM715]

Absolutely correct! For a deuce the shift rail for first and reverse extends out the back of the transmission, that connects to the Tcase (sprag only) which then moves the shift fork for the overriding clutches to engage either the forward sprag or the reverse sprag. A five ton is air actuated vs linkage for a deuce.

For the OP, your title says front axle is not engaging, but the post reads as though you are concerned about having a switch... What's the actual problem? No 6x6? Or are you wanting know what transfer case you have?

But it is NOT locked in in first or reverse. It only moves the sprag clutch from forward to reverse and that is the part that "senses" the rears slipping and engages the front driveshaft. The front axle will only pull when the rears slip.

 

[searls84]

You are wrong. It is not "locked in" in any gear. Read section 86 in TM9-1819B which describes how the single sprag and dual sprag work.

Partner, you are the one who said it was "locked in" in ALL gears. Read the first sentence of post 14. Just because you can read the TM doesn't mean you understand it.