modern receiver hitch and M37

[John Mc]

I forgot to ask: other than the drop, are there things you've found that you wish were a bit different? Would you move the receiver fore or aft if you had the choice?

I agree that I'm not about to try to modify the hitch myself. Even our local welding guru has told me that his insurance does not want him welding on towing/hitch equipment. (He does custom work on tractors and logging equipment, so his skill is definitely up to it, but I can understand why the insurance co. would draw the line on hitch work.) However, since I'm shopping for aftermarket hitches anyway, I might as well shop for as close to an ideal set up as possible.

By the way - I understand you know Tim Holloway of Distinctive Restorations. I live a few miles from him. He's going to be doing some work on "Brutus" (my M37) shortly - we'll be rebuilding the transmission and transfer case, along with a few other things.

[Doc Dave]

I have not used it yet; the truck is not done.
So, I can't say how I like it in operation but I can't see it would be an issue.

Paul Mierop who lives about an hour from you and Tim, has information on his "you can do this" tutorial pages, from back when he built various power wagons. He also mentions a hitch he found that fit the civvie flatfender, so may fit the M37 well. His M37 is modified but has a lot of good stuff in the section on it. Look at the section on "Bumblebee" for the hitch.

check this out:
http://imageevent.com/moosecreekmaple

[John Mc]

Thanks for the additional info and leads.

[Doc Dave]

See this link from Paul's site:
i think it may be overkill to have the hitch flanges up to the top frame flanges, but that gets it up higher compared to the pintle. Harder to accomplish due to clearance with what I used, but with Paul's Draw Tite?

http://imageevent.com/moosecreekmapl...h83qk1.camel_s

[Doc Dave]

Extra info- I measured the vertical distance on my hitch from the bottom of the receiver up to the hitch flange, and it was 9". I think the hitch people refer to this dimension as the "rise".
just for grins, I looked at Draw-Tite's on line site for receiver hitches. They have a class 3 (similar rating as this one) with a 7" rise. If I experience difficulty with my hitch on the M37 as to clearance, I would consider the a Draw Tite one as I believe the receiver would be 2" closer to the truck frame.

[John Mc]

Doc Dave - Where are you finding the rise specifications on the Draw-Tite site? I've not been able to find them on the Draw-Tite website or on eTrailer, so most of my browsing has been eyeballing the pictures and trying to guess the rise.

[Doc Dave]

You have to click on tech specifications. See this link:

https://www.draw-tite.com/products/t...bv2qPLRmhm5NVU

I have not checked my frame width to see if this works ( I know it is pretty standard). But, as to rise or height, this one shows a "height" of only 7". So it would not hang down as far I think.

[John Mc]

The only specs I saw on there were "shipping dimensions". I was not sure how much to trust that for estimating the rise, although I guess the actual rise could not be bigger than that dimension.

[John Mc]

On my M37, all you need is about 3/4" drop from top of the hitch's mounting flange (where it bolts to the truck frame) to the top of the hitch crossbar in order to just miss the lowest point on the truck's rear cross member (the rounded drop under where the pintle hitch mounts). The pintle actually hangs down a bit lower, so you'll need to make sure the hitch cross bar is far enough forward (for example, under the rear cross member) so it does not interfere with the pintle. If the receiver tube mounts on the underside of the hitch cross bar, this will leave plenty of room for the pintle. (On some hitches, the receiver tube mounts at the same height as the cross bar, so with this style, you'd need a bit more drop so the receiver tube will also clear the pintle.)

I found a used hitch off a 2000 Jeep Cherokee with very little drop: about 1.75" - so only about 1" more than necessary. It fits with only a minor modifications: the outside of the mounting flange is a bit wider than the trucks frame, so you have to grind about 3/16" off the outside edge of the hitch's flanges for clearance around where the rear leaf spring mounts to the frame. Other than that, just drill appropriate holes in the frame for mounting. Drilling out the rivet that holds the truck's rear cross member to the frame makes a pretty good spot for the rear-most mounting hole on the receiver hitch. You might want to slide the hitch forward a bit, tucking it in a bit more under the rear cross member and avoid having to drill out the rivets. Etrailer does sell this hitch: Draw-Tite # 75054. The main downside is that the hitch is only rated for 3500# GTW / 350# TW. The guy who installed it for me had read me the weight distributing hitch rating of 5000#/500# - but I don't have any trailers with weight distributing hitches. I wanted more than 3500#, So I ended up pulling this hitch off.

eTrailer also sells another hitch to fit a Jeep Cherokee rated at 5000# GTW, the Curt 13084 It's hard to tell from the pictures, but it appears that the 5000# rated hitch may have slightly more drop. It might be a good choice for someone wanting to mount an unmodified hitch on their M37 with a higher weight rating than the Draw-Tite 75054.

I'm thinking I'm going to order an aftermarket hitch and have it modified to reduce the amount of drop, so I lose as little ground clearance as possible. Is your 2001 Dodge Ram that you pulled the hitch off that fit your M37 a 6 1/2 foot bed, or an 8' bed? Apparently the two beds take a slightly different hitch. I'd like to start with one that is likely to fit mine, so I'll order an aftermarket that matches your bed size.

[Doc Dave]

Mine is 8’
I agree you would wan t at least a class 3 or 4; think that was stock on the modern pickup. In my diesel I put in a class 5 so I could pull a heavy trailer if I needed to.
please post pics of what you come up with

[John Mc]

I eventually ordered a Draw Tite #41536 receiver, It's rated at 6000# (or 10,000# with a weight distributing hitch). I won't be using a WD hitch with it, so 6000# it is. I will occasionally exceed 5000# (a small log forwarding trailer with a load of logs), however, that will be for short distances and lower speeds (about 5 miles @ 25 MPH or less)

Taking a cue from Doc Dave, I drilled out the rivets which mount the truck's rear cross-member to the frame and lined the rear-most holes in the hitch with the holes where the rivets were. The hitch mounting flange was a perfect match: no need to grind anything to make it fit. Here it is on the truck with just one bolt through the old rivet hole on each side):

hitch rear.jpg
The top of the hitch cross-member sits about 2.5" below the lowest point of the truck's rear cross-member (that little bulge below the pintle hitch), or about 3.2" below the truck frame. That's lower than I would like.


Hitch side.jpg
Hard to see in the picture above, but the front of the hitch cross-bar sits about 1/4" behind the rear of the truck's rear cross-member. That puts the receiver cross-tube roughly 3" further back than I would like.

Hitch Pintle detail.jpg
2.5" from lowest point of pintle to top of the hitch cross-bar. The receiver tube sits another 2.5" below that.

If someone were happy with this amount of drop, they could simply bolt the hitch on in this location. Just a few holes to drill. In fact, they could slide the hitch forward a bit to tuck the hitch cross member under the truck cross member, and drill the holes there, without drilling out the rivets holding the rear cross member

My plan is to cut the hitch cross member off and move it up a couple inches, and forward to sit under the truck's rear cross-member and leave just a bit of clearance between the two. There will still be plenty of clearance between the pintle and the receiver tube. The truck and hitch go in to the local fab shop tomorrow to make these changes. (I don't trust my welding enough to do that myself.)

I'll post some picture of it when the modifications are finished

[Doc Dave]

Thats an improvement over mine. I may end up doing what you did to get the lower "drop" height.
I could always sell me original hitch on eBay or CL.

[John Mc]

Thats an improvement over mine. I may end up doing what you did to get the lower "drop" height.
I could always sell me original hitch on eBay or CL.

If you are happy with the amount of drop on the hitch as shown, it's just a straight bolt-on process. If I were going that way, I would probably slide the whole thing forward 2 or 3" to tuck it under the truck's rear cross member. The only difficult part of the installation is going to be getting the front-most bolts installed on the receiver, due to the fact that you can't just reach up and drop the bolt in easily, since the frame and gas tank are so close together at that point. Fortunately, the hitch hardware includes carriage bolts, which have the little square under the head and some small rectangular "keeper plates" with a square hole on them, so it's just a matter of reaching in with something to drop the plate and bolt in place. The plate will then keep the bolt from turning when tightening the nut.

I want all the ground clearance I can get, since I regularly run this truck up and down some trails in the woods. The more clearance the better when driving through the erosion control waterbars. Because of the shape of the hitch's side plates, moving the cross bar up on it also requires moving it forward. I think I will end up right where I want to be after the hitch modification by using the truck's rear cross member rivet holes.

[John Mc]

Here is the modified hitch. (done by someone a whole lot better at welding than I am.) I don't have all the bolt holes drilled yet, but this is sitting in its final position. The hitch just barely misses the downward bulge in the rear cross-member on the truck. The crossbar on the hitch is just about aligned with the truck's rear cross-member fore & aft. Still a good bit of room around the pintle hitch.

Actual installation was easy: Drill out the rivet on each side mounting the truck's cross-member to the frame. Use the hitch as a guide to mark and drill the remaining two holes on each side (once marked, I removed the receiver for drilling). I drilled the holes at 9/16" to allow easy installation of the 1/2" mounting bolts included with the kit. The only tricky part was getting the bolts installed in the forward-most mounting hole on each side. The gas tank comes so close to the frame that getting the bolt in place is a bit tricky. The mounting bolts are carriage bolts. The hardware kit includes rectangular "washers" with square holes to capture the square part just under the head of the carriage bolt, the rectangular washers jam against the frame when tightening, so no problems tightening the bolts, despite being unable to reach the head of the bolt. I stacked the bolt in the rectangular washer and pushed it along with a bent coat hanger until the bolt lined up and dropped though the hole.

Hitch Mod1.jpg

Hitch Mod3.jpg

Hitch Mod4.jpg