M1078 Brakes

[cavetech]

Does an M1078 have spring brakes like a civilian vehicle?

I may not be asking this correctly.

If you lose air pressure in either brake system do the brakes come on to prevent a runaway vehicle?

Thanks, Steve

 

[Derrickl112]

.

 

[cavetech]

Yes.

Wow, that was quick!

Thanks

 

[DiverDarrell]

If you don't have air pressure, you don't get to go anywhere. Standard wedge air brake system.

 

[cavetech]

If you don't have air pressure, you don't get to go anywhere. Standard wedge air brake system.

Yes, should be a safety feature, lose air pressure and brakes come on.

OK, I'm going for some remaining questions:
1.The M1078 doesn't have a switch for High/Low range that I have found. So it doesn,t have two ranges?
2. When in 4 wheel drive do all 4 wheels grab because both differentials aren't limited slip?
3. With all 4 wheel driving the steering should get difficult because the front differential should be limited slip?
4. I am just confused about this type of truck's type of 4 wheel drive.

 

[coachgeo]

HOPE THIS HELPS Answers included below .

.....

.The M1078 doesn't have a switch for High/Low range that I have found. So it doesn't,t have two ranges?

Yes and No.
No- as in there is no two selectable ranges, but that is because it is not needed. This truck has a different transmission/T-case design than a typical transfercase setup. Its design does not need a separate "Hi-Low lever or button to gain access to all the gear ratios except the Granny Gear. Unfortunately; just to confuse everyone the Granny gear is called "First Gear".

Yes- because all the available ratios are pretty much the same in both designs. Granted Granny/First on this truck is ONLY available by push button selecting it when in offroad mode.

Here is how I look at it. Would be interested in others thoughts in here. With first gear like a Granny Low gear.... then Second gear would be an equivalent to the lowest typical gear ratio on an average 4wd truck's LOW setting. Third thru fifth on FMTV's are closer to your more typical ratios found in a 4wd HI setting.

FWIW... Second Gear thru 7th gear physically reside inside the Allison Transmission and Granny/First Gear (available only in Off road Mode) physically resides inside the AWD T-case.

2. When in 4 wheel drive do all 4 wheels grab because both differentials aren't limited slip?

All wheels grab till one slips like any axle with a differential. There is no limited slip or locker. There is some slip designed into the AWD transfer case too in order to keep things from binding

3. With all 4 wheel driving the steering should get difficult because the front differential should be limited slip?

????? 999.99% front differentials in a 4wd system have no limited slip or locker

4. I am just confused about this type of truck's type of 4 wheel drive.

It is a FULL TIME ALL WHEEL DRIVE not 4wd. There is two modes. Highway and Offroad. Again, First gear is ONLY available in this mode.

In these AWD FMTV trucks AWD is always on and in normal in highway mode clutches inside the TCase move 30% of power to front axle and 70 to the rear for total of 100% . Now what happens is in Off-road mode is selected? via Computer, things get manipulated inside the AWD transfercase. It causes clutches to bind harder which in turn causes the output to the front and rear axle to now be 50% of power each for total of 100%. . This is same as a typical 4wd transfercase split of power.

PS- A Detroit is Available for rear. NEVER put a Locker in front axle of an AWD vehicle unless it is selectable and then use it VERY Rarely if ever.

 

[sargentwolf]

To access first gear you have to select it. On the transmission controller, while stopped, hit MODE, then arrow down until it shows 1. Your now locked in first gear.

 

[DiverDarrell]

When in Mode and in first gear, power output is locked 50/50 front and rear. Normal driving the transmission range is gears 2-7, when you want low gear you have to stop, and down shift on the key pad. Then 1st gear is selected and locked there until you shift out. 7sp tranny with a granny low first is another way to look at it.

 

[DiverDarrell]

As far as power to wheels. Each wheel has power to it until one loses traction. Due to the open diff the spinning tire steals all the power. A way to transfer some of the power from the spinning wheel to the one with traction is to apply some brakes, and gas at the same time.this forces power back to both wheels and you have to drive thru the brakes. Poor mans locker. I have used it more times than I can remember to get loaded 2 & 3 axle trucks out of muddy fields.