DatGuyC's hmmwv project thread

[DatGuyC]

I've got some projects I'm working on with my truck and figured people might not only be interested in the stuff I'm doing but could offer expertise I don't have. The main project right now is swapping in a cummins 12 valve from a 1995 ram 3500 and using the dodge 47rh transmission. This thread will kinda be a dumping ground of stuff I've done and what I plan on doing in the future. A place to put ideas out there and get feedback, good or bad. This is a side project and I'm in no rush so the progress will be slow but I hope to really get into it when it warms up outside. I usually have several different projects going on at the same time so it might get jumbled up but whatever, that's how I work. If you see anything you want more information on then feel free to ask, this is a learning thread for everyone.

So far completed:
Refreshed the cummins with lots of new parts
Rebuilt the 47rh to be stronger than stock
Swapped inputs on the np242 so it mates with the 47rhs 23 spline output shaft
2" body lift on the hmmwv
swapped the garbage stock brake switch for a more normal automotive one
reverse lights
Ibis tek light bar with more robust 1/8 steel brackets
front high-back seats
H1 trailer hitch
4 man divider
interior lights
24 bolt wheels/tires
A2 Airlift bumper
Rhino tire carrier
All new soft top kit
Halogen headlights with replaceable 100 watt bulbs, they are a lot better than the sealed beams
Rubber matt on the tunnel
other stuff that I dont remember haha

Current projects as of the beginning of this thread:
Rear blockout bar to cover the gap left by the 2" body lift
Adding rear AUX fuel tank
Electric speedometer swap
rear fender AC condensers

I've taken a lot of pictures over the years so as I find them I might make posts about that little project. For the first pictures I'm going to have a before and after just to see how far its come. The first picture is when it first got delivered off the rollback, the last one was taken this summer and is pretty much how it sits now.

 

[Flyingvan911]

Nice!

 

[DatGuyC]

I've been talking with skrilex about adapting the np242 to the back of the 47rh since we both want to keep the AWD on our cummins swaps. The stock input for the np242 has 32 splines and the output shaft for the 47rh has 23 splines. Luckily there are tons of gears that swap around on these transfer cases so there is usually one that will work. For my late model 242 (4 bolts on the output housing) I needed an input gear for a 94+ jeep np231/241. This has the later cut gear teeth with the narrow bearing.

Comparing the stock 32 spline input to the 23 spline jeep input







On the back of the 47rh





He had some questions about the needle bearing that goes inside the input gear and if it can be removed/replaced. I didn't know so I went and looked at the old stock input and sure enough it can be pushed out. There doesn't seem to be any lip or anything that would stop the bearing at a certain depth when being installed, so I dont know how its decided on how far it should be seated. The part number on the bearing is: DB-95856






According to this thread, the input gear lengths are different for the 47RH and 47RE, so keep that in mind if you have the RE.

http://www.cumminsforum.com/forum/98-5-02-powertrain/1634530-94-95-47rh-241dhd-47re.html

 

[Skrilex]

So does it seem like a clocking ring will be required to get correct positioning? I must have a RE overdrive unit because if I had a similar length t case gear in 23 spline as you do there I’d need to cut it down to get it mated to my overdrive. Hopefully this overdrive doesn’t have a problem mating to my 2wd a618. But, if a clocking ring is required I could make it out of 1/2” material and the gear would be perfect length then.

 

[DatGuyC]

So does it seem like a clocking ring will be required to get correct positioning? I must have a RE overdrive unit because if I had a similar length t case gear in 23 spline as you do there I’d need to cut it down to get it mated to my overdrive. Hopefully this overdrive doesn’t have a problem mating to my 2wd a618. But, if a clocking ring is required I could make it out of 1/2” material and the gear would be perfect length then.

I think we need to see what you actually have in the truck first. A 47RE 4wd overdrive unit will not work on a 47RH body. If you go under the truck there should be a yellow plug on the transmission like in the picture. If it has 3 pins its a RH, I think the RE has like 8.



As for the clocking ring, I don't think its necessary. Both transmissions have the TC drop on the same side.

 

[SCM35A2]

Nice projects!

 

[Skrilex]

I think we need to see what you actually have in the truck first. A 47RE 4wd overdrive unit will not work on a 47RH body. If you go under the truck there should be a yellow plug on the transmission like in the picture. If it has 3 pins its a RH, I think the RE has like 8.

View attachment 718445

As for the clocking ring, I don't think its necessary. Both transmissions have the TC drop on the same side.

Thanks for that. I’ll get under the truck and see tomorrow. The truck is very low so it’s hard to get under there lol. The paperwork says a618 though and the housings seem to cross over.

 

[Skrilex]

Okay i definitely have a 2 pin plug. So I either have a 47rh or a a618, or those are the same. Or they are the same except the bellhousing? Dang well are all the OD units the same 23 spline? At least I can continue with that side of the project lol.
I guess I was mislead or wishfully thinking this 46re unit would work.

 

[DatGuyC]

Okay i definitely have a 2 pin plug. So I either have a 47rh or a a618, or those are the same. Or they are the same except the bellhousing? Dang well are all the OD units the same 23 spline? At least I can continue with that side of the project lol.
I guess I was mislead or wishfully thinking this 46re unit would work.

As far as I know all 47rh/47re/48re are in the a618 family. If you only have a 2 pin plug you might have a 46rh since a 47rh has a 3 pin plug. Sounds like you still have the stock transmission?

"1991.5-1993:A518 (aka 46RH) 4-speed. Overdrive, no lockup."
http://www.cumminsforum.com/forum/g...transmission-lockup-non-lockup-converter.html

Looked on ebay and there seem to be 4x4 overdrive units available for about $500, or it might be worth it to you to upgrade to a 47rh for the extra strength and torque converter lockup. With the lower max rpm of the cummins you might want the lockup when cruising on the highway to keep rpms and heat down.

 

[Skrilex]

That might make sense. I have a rebuild sheet from a shop here that says it’s an a618 but that could be incorrect. I also thought I read that the diesels always had the 618 and the gas models used the 518.

 

[Skrilex]

Got a different input shaft today and third time is the charm. So the part I found to fit was Jeep TJ, np231, 97-02. My previous attempts were too short, or wrong bearing. Just wanted to add to this helpful thread.
Oh also the input shaft we want for this needs to be the 5-1/8” long with narrow bearing.

 

[AOR]

Hello DatGuyC's I am new to the HMMWV crowd. I would like to check out you HMMWV I am one town north of you in Burtonsville and I have a pile of Jeep transfer cases if you still need any parts. They used multiple lengths on the input gears on the 23 spline 231 Jeep transfer cases. The 32RH auto being the longest
Teraflex makes an adapter seal housing that may be able to be used in certain setups.

 

[DatGuyC]

I have my transfer case all put together so I should be good on parts. If you wanted to meet up one weekend I wouldn't mind swapping some hmmwv stories.

 

[JoeJrTheBarber]

Very nice machine ...

 

[AOR]

I have my transfer case all put together so I should be good on parts. If you wanted to meet up one weekend I wouldn't mind swapping some hmmwv stories.

Definitely I am always looking to network with local people. My background is Jeeps but I am learning about the HMMWV quickly. Would like to see that Cummins conversion we are currently working on an old 12 valve truck that came from out west

 

[Skrilex]

Buying cars from out west is smart. Here’s in Oregon it’s rains a lot but interestingly that preserves the cars. We don’t use road salt and we don’t have brutal sun so the cars out here are often rust free and in great shape.

My power pack is almost ready to toss in the frame.

 

[DatGuyC]

Definitely I am always looking to network with local people. My background is Jeeps but I am learning about the HMMWV quickly. Would like to see that Cummins conversion we are currently working on an old 12 valve truck that came from out west

Mines not converted yet, I just have most of the parts and am waiting till things settle down at home to start on it.

Buying cars from out west is smart. Here’s in Oregon it’s rains a lot but interestingly that preserves the cars. We don’t use road salt and we don’t have brutal sun so the cars out here are often rust free and in great shape.
My power pack is almost ready to toss in the frame.

What type of motor mounts are you using? I cant remember if you did a body lift or not.

 

[Skrilex]

I’m going to use the hmmwv mounts if possible. Wont know till I fit it I guess. I think that’s what steelsoldiers did. Looked like it worked out well.

What did you select for a fuel lift pump? I am lost in reviews and I’m not going to spend 600$ on some fancy thing, especially without perfect reviews. I don’t want to turn up past 250hp so I don’t need many many gph.

 

[DatGuyC]

I was just going to use the mechanical pump on the side on the engine, do you think you need a lift pump?

 

[Skrilex]

Several people swayed me to think the stock pump is not reliable and dangerous for the fuel system at any power level over stock, however, I’m starting to doubt that sentiment. I’m thinking going back to stock but also put a fuel pressure sensing device.