I need some help getting my M37 on the road. Trans, brakes, steering

[WCRiot]

Hey guys,
I'm finally picking up that Chevy 350 powered M37 I posted about a while back. The seller had been out of town every weekend since i saw the truck in person. As a follow up the truck has:
Chevrolet 350 engine, Sm420 Transmission. I don't know the exact tire size but its not stock as the rims are custom made.

So what I know I want to do immediately, as I am trying to get the truck comfortably driveable this summer.
I need to find a different transmission that will bolt up to my Chevy small block and will work comfortably with the 2 speed transfer case, as I do NOT want to have the truck in 4wd mode all the time. What transmission do you recommend? Changing the differential gear ratios is an option, but its expensive to do. TH-400 is a 3 speed auto trans, which might work well. Maybe a 700-r4 but, I dont know much about these transmissions

I am going to buy Ray's Disc Brake kit for the front brakes, I may eventually buy the rear brake kit down the road.
Does anyone have more details on the isntallation of this disc brake kit? I'd like to see some detailed pictures or some step by step pictures.
What are you guys using for a master cylinder when you do the disc brakes?

I'd also like to add power steering to the truck, eventually. I have seen the snake river stuff, but I'd like to see some other options. And more details with some more pictures to help me understand what is required to make a power steering swap work.

 

[M543A2]

I have no experience with the disc brakes or power steering kits. I am puzzled however by your comment about needing s different transmission so you do not have to drive in 4 wheel drive all the time. Why does the SM420 force you to drive in 4x4, if that is what you are saying? 2x4 or 4x4 is decided in the transfer case.
When looking into automatics, you may have to consider the tail shaft length. The SM420 is a good transmission, and is short in length.

Regards Marti

 

[Capt.Marion]

g741.org ==> their forums should have a LOT more information, especially in the realm of transmissions and the disc brake questions.

 

[m376x6]

I find this forum has a lot more knowledge floating around than over at G741. That forum has an issue that prevents a lot of folks from participating in it.

What year is the M37, not 1965 by chance. I can offer you first hand knowledge of it if it is. I know of only one person so far to adapt a military NP420 to a SB Chevy. And I can't resist:



I believe Helitool has an active website, a simple search for Helitool should bring it up. They specialize in helicopters if I recall. But they offer a kit for disc brakes and all the instructions. Does your new to you truck have a winch setup? Best of luck. There are a lot of knowledgeable folks on here, they just don't post real often on M37's.

 

[WCRiot]

I have no experience with the disc brakes or power steering kits. I am puzzled however by your comment about needing s different transmission so you do not have to drive in 4 wheel drive all the time. Why does the SM420 force you to drive in 4x4, if that is what you are saying? 2x4 or 4x4 is decided in the transfer case.
When looking into automatics, you may have to consider the tail shaft length. The SM420 is a good transmission, and is short in length.

Regards Marti

Let me clarify this. The SM420 allows the truck to be in 2wd mode as much as I want. I use the transfer case to put the truck in 4wd hi and 4wd low, Just like everyone else.

My question was: I would like to retain this feature, meaning I would like to keep the transfer case. But the gearing of the SM420 transmission is way too short in my opinion and I would like to find something that would get me some more speed.

"m376x6"
I promise I will get some pictures posted soon. The truck is NOT a winch truck, but I am okay with If I feel like I need a winch, Ill put somethign more modern on. I'm no purist!

I'm on g7401 and like some of the work they do, but I get alot of long winded answers over there.

In terms of power steering: I have learned alot from the g7401 guys, but I would really like to see some instlaled pictures so I have an idea of how I should mount the steerin box. Also, Id like to see what some steering box choices are.
They told me a Toyota F20 or something like that, box would be best for the stock axle setup.

 

[deloit]

power wagon advertiser has some good m37 threads also.

 

[bubba_got_you]

how fast will it go? i would not run a m37 more than 65 mph (that should be fast enough and if you need to go faster than 65 you are in the wrong truck )

 

[WCRiot]

how fast will it go? i would not run a m37 more than 65 mph (that should be fast enough and if you need to go faster than 65 you are in the wrong truck )

65 sounds good!

 

[Eric's hifim37]

I agree with the 65 MPH max, I have driven mine @ 70 + and the wind noise from the flat windshield is horrible @ 60 - 65 much more pleasant, I do have V8, modern tires, disc brakes, power steering and all that jazz but after I built the truck and tried to drive it like a new Ram I had to face the reality it is a utiltiy vehicle and never will be able to match what we have to drive these days. For sure you better not have a soft top and drive over 45 your you will learn a lesson, I mostly drive mine to work locally and twice a year to Tower Park but I'm crusing it no more than 60, plus the truck seems to not feel so stressed out. I get to see if my sythetic oil works in the transfer case this run, so far it is looking like a winner. I am going to keep my temp gun handy and check temps at my stops to see how much cooler the transfer is running. My only thought is this time I am pulling a loaded trailer and my load on the truck will be the most I have ever tried before for such a distance so wish me luck !

Eric..

 

[Varyag]

I am running a 350 with a SM420 in my 67 FJ40 and 65 is not out of the question at all. I have 410 gearing in the pumpkins. I agree that is about as fast as you would ever want to take these old rigs.

 

[WCRiot]

I am running a 350 with a SM420 in my 67 FJ40 and 65 is not out of the question at all. I have 410 gearing in the pumpkins. I agree that is about as fast as you would ever want to take these old rigs.

In terms of gearing, the m37 is 5.83 stock. I can spend a boat load of money to change the gearing to 4.89 but thats still pretty far off from your 4.10 gears.

 

[bubba_got_you]

65 sounds good!

so what is the top speed as it sits?

 

[WCRiot]

so what is the top speed as it sits?

The truck doesnt have an RPM gauge so I am scared to see go too fast. I'm worried that I would be cruising in Redline or something like that.

I'm going to wire a tach up so I can see where I am with engine speed. But, the tach isn't working either, so I will need to fix that in order to figure out vehicle speed.

 

[bubba_got_you]

The truck doesnt have an RPM gauge so I am scared to see go too fast. I'm worried that I would be cruising in Redline or something like that.

I'm going to wire a tach up so I can see where I am with engine speed. But, the tach isn't working either, so I will need to fix that in order to figure out vehicle speed.

i would say do those things then we will look in to speed. it may do 65 just fine but you just don’t know it. also toss the mechanical fan and get a 16" electric fan. i just got 2 of them (they push or pull 2500cfm each) for my GMC and paid $72 for both shipped so they are not expensive and it will keep that motor nice and cool.

 

[WCRiot]

electric fan was on my list of things to do. I'm use to cars with bad cooling

 

[SasquatchSanta]

Concerning an alternate transmission "If" you don't have a winch and therefore don't need a PTO you can replace both your current transmission and transfer case by install a 350 automatic transmission complete with the standard automatic bolt on transfer case. To do so you will have to remove the rear axle assembly and flip it. The spring mounting brackets will have to be re-positioined on the opposite side of the housing and the old breather tube plugged and a new one installed on the other side of the housing. Then --- when you remove the differential housing (pumpkin) --- flip it 180 degrees and re-install it the new center discharge transfer case will then line up with the re-positioned (now centered) pumpkin.

This will give you a modern "and quiet" transmission and transfer case. I believe some of the 350 automatic transmissions are overdrives.

The only draw back is no emergency brake --- and no transfer case whine.

I'm looking at dong this modification only using a 205 transfer case with an emergency brake drum installed on the case.