M977 HEMTT Acquisition

[HASSON1911]

Hey guys as you can see i need a little help with labeling and what all the switches do.I'm not quite sure the route i want to go to label these they are a little weird to duplicate, but anyways its some eye candy for you boys, its actually a lot simpler operation than i was expecting.

 

[Stalwart]

Congrats, welcome to the HEMTT club. Are you planning a full restoration of just patch as it needs to be serviceable?

 

[HASSON1911]

More than likely with continuing medic school a patch as I go, I do plan a full restoration as an end game plan that will be able to speed up after school. One thing I didnt know and I dont know how many other people know but that these engines are turbo AND supercharged.

Awesome truck by the way I wish I could get a hold of a cargo cover for reasonable price also I plan on painting her back to a 3 camo scheme!!!

 

[Stalwart]

The supercharger isn't really used as such, it provides little boost, it is simply an air pump to scavenge the cylinders of exhaust gasses and all 4 valves in the head are for exhaust. I was able to get the new (NOS) cover for $200 shipped and the bows from a guy here on SS. I had new bed sides made out of aluminum but unlike the stock HEMTT, I can lower one of my sides with the cover on. Plus my sides are cab height . . . oh, and I have the 5 speed transmission. Has your transmission been changed back to ATF from the std. motor oil?

 

[JohnnyBM931A2]

Thanks for the pics guys.. Awesome stuff

 

[HASSON1911]

The supercharger isn't really used as such, it provides little boost, it is simply an air pump to scavenge the cylinders of exhaust gasses and all 4 valves in the head are for exhaust. I was able to get the new (NOS) cover for $200 shipped and the bows from a guy here on SS. I had new bed sides made out of aluminum but unlike the stock HEMTT, I can lower one of my sides with the cover on. Plus my sides are cab height . . . oh, and I have the 5 speed transmission. Has your transmission been changed back to ATF from the std. motor oil?

Very nice and score on that deal, I just thought it was quite interesting they decided to do both kinda unheard of superchargers in Military vehicles i thought but times are changing. Once I order all the filters all fluids will be changed I'm also adding a coolant filter system to. I looked at the fluids and deemed it safe to do just a quick operational check and drive her a little before i left back for school. I fully assume its motor oil in the tranny and subsequently i believed I felt some slippage when the truck was trying to up-shift. So no more driving until fluids are changed, and the secondary air is restored to a more permanent fix. Also nice score on the 5 speed mine is the 4 speed.

Also, how are you liking that HEMAT? Curious if I should pick one up.

 

[Stalwart]

It was a crying shame the Army wanted to stock one less lubricant and put motor oil in the transmissions! When mine came out it was shot and the prior owner decided that if he had to pay for a full rebuild, it might as well be a 5 speed. I've heard the lifetime of the transmissions with motor oil was often much less than a year. Once clutches start slipping they are TOAST very quickly. With the narrow power band of the Driptroit I wish I had a 6-7 speed. I can't even imagine a 4 speed, every shift I just barely fall out of the power band. Of course, I live in a VERY hilly area, it might not make a difference where you live. Set up right, you can take your hands off the wheel at 60 and the truck will just go straight until you hit something.

As Wreckerman said, you will hit the roof with your head if you encounter a bump in the road at speed. I'm not talking about a curb, I'm talking a badly worn expansion joint on the freeway. Even the A3's and A4's with air suspension, from what I've been told, aren't much better. One thing however, you'll never overload it, I've been told by someone versed on the axles and components you'd have to get near 130,000 lbs before the axles meet their rated max weight, same for the tires . . . I run mine a 50 PSI rear and 60 front to take a bit of the bounce out of it. Oh, and yes, the longest MUST be torqued to insane values or installed by a tire shop. You need 600 lb.ft on the fronts and about 525 in the rear. If you don't do that and stretch the studs, a wheel will back off completely in a couple of miles. A long handled 1/2" breaker bar WILL NOT WORK!

My interior isn't quite stock

 

[lindsey97]

I think that Detroit engines equipped with superchargers have been used in military vehicles and boats dating back to WW2.

 

[Stalwart]

Detroit 2 stroke Diesels will not run without the supercharger, it is part of the induction system. If you let off the fuel cutoff at just right time, the engine will run backwards.

 

[emmado22]

The "canvas" sounds like a great idea, but put one on and take it off once, you will never want to do it again. We had the bows and canvas, but never used them as they were a PITA....

 

[Stalwart]

My modifications allows my wife and I to go from fully enclosed to topless with the bows stowed in 4-5 minutes EASY! It is less than 10 min to completely put up the top and have it ready to roll down the road. Stock, this is NOT the case, PITA! I even made bow stowage rack for my custom 1 piece bows and header for the center right bed side door to fold down with the bows up.

 

[HASSON1911]

It was a crying shame the Army wanted to stock one less lubricant and put motor oil in the transmissions! When mine came out it was shot and the prior owner decided that if he had to pay for a full rebuild, it might as well be a 5 speed. I've heard the lifetime of the transmissions with motor oil was often much less than a year. Once clutches start slipping they are TOAST very quickly. With the narrow power band of the Driptroit I wish I had a 6-7 speed. I can't even imagine a 4 speed, every shift I just barely fall out of the power band. Of course, I live in a VERY hilly area, it might not make a difference where you live. Set up right, you can take your hands off the wheel at 60 and the truck will just go straight until you hit something.

As Wreckerman said, you will hit the roof with your head if you encounter a bump in the road at speed. I'm not talking about a curb, I'm talking a badly worn expansion joint on the freeway. Even the A3's and A4's with air suspension, from what I've been told, aren't much better. One thing however, you'll never overload it, I've been told by someone versed on the axles and components you'd have to get near 130,000 lbs before the axles meet their rated max weight, same for the tires . . . I run mine a 50 PSI rear and 60 front to take a bit of the bounce out of it. Oh, and yes, the longest MUST be torqued to insane values or installed by a tire shop. You need 600 lb.ft on the fronts and about 525 in the rear. If you don't do that and stretch the studs, a wheel will back off completely in a couple of miles. A long handled 1/2" breaker bar WILL NOT WORK!

My interior isn't quite stock
View attachment 581720View attachment 581719View attachment 581721

You have such nice set up I wish we lived closer so I could come over and steal some of the concepts you have, I mainly wish I could see your cab and every angle as I do plan to follow something close to yours as far as cleanliness and function-ability goes. What did that rebuild cost you, im sitting at 22k miles and in the door is etched 2011 and miles 14k so with in the last 4 years it was operational(ish) for another 8k recent miles so if ran with motor oil im probably going to expect a trip to allison soon.. Right now I got my tires at 80psi per TM specs also keeping them there as itll be sitting for a while so if i didn't get the air leaks in the valve steam elbows completely sealed itll buy me a little more time tilll i get back to air them up.

 

[Alexsha]

My modifications allows my wife and I to go from fully enclosed to topless with the bows stowed in 4-5 minutes EASY!

Sounds like a good time...

 

[HASSON1911]

We got air! Spent the weekend partly fixing new air hoses, and finally got air in both primary and secondary, my question though is aren't the both supposed to fill to 120-125psi? I'm guessing bad regulator on the primary?

 

[akroessler]

awesome build my friend, quite jealous of your 977. was looking into getting one when funds are more readily available! look forward to seeing more of the build and pictures/videos as time progresses.

 

[Piper Cub]

Looks like a real fun truck, congrats! akroesler, howdy neighbor! Welcome from Palmdale (technically sitting in Flagstaff now but everything's in Palmdale).

 

[akroessler]

Looks like a real fun truck, congrats! akroesler, howdy neighbor! Welcome from Palmdale (technically sitting in Flagstaff now but everything's in Palmdale).

hey there! i work in Palmdale so im very familiar. what kind of trucks can we find out here??

 

[jjb]

Is the Jake break working? After I put a new engine in mine I left the Jake unhooked as it wasn't working right before. I want to hook it back up but I'm not sure where all of the wires go.

I have all of the manuals but the wire schematics are confusing.

So far I have replaced the motor, alternator, batteries and the PTO solenoid. I also removed the ether start system and added a block heater. Lots of work but these trucks are awesome.

 

[HASSON1911]

Is the Jake break working? After I put a new engine in mine I left the Jake unhooked as it wasn't working right before. I want to hook it back up but I'm not sure where all of the wires go.

I have all of the manuals but the wire schematics are confusing.

So far I have replaced the motor, alternator, batteries and the PTO solenoid. I also removed the ether start system and added a block heater. Lots of work but these trucks are awesome.

No clue yet I may try it to verify operability, but to be honest I have no reason to use it, I know they work and do a heck of a job but Ill never have a load to justify using it and the amount of pressure it puts on the engine is quite substantial and doesnt sit well with me as far as "just to use it'', I too am working on the dash area, luckily about 90% of the wiring is still functional including high idle for the crane!

 

[dk8019]

I've used my Jake a few times on the descents over the winding mountain passes between Cleveland, VA and Lebanon, VA. First truck I've driven with one, and man is it nice compared to riding the brakes. If I have one complaint about the HEMTT its that the air tanks very quickly drain with repetitive use of the braking system!