M37 Front Cross-member Mods

[MasterYota]

Has anyone had any luck with modifying or creating a new front crossmember in the M37's? I'd like to build a newer flat crossmember so that I can move the front diff forward a little to better sit the tires in the fenderwell. I'm installing a Dana 60 in the front with high-steer so I'll need the room for the steering linkage to clear regardless of where the diff is located (stock or forward)...

I'm just wondering if anyone has any pictures, or material recomendations, or just general thoughts on the matter. Its going to happen one way or another, but I'd rather not repeat anyone elses misadventures in the process.

I don't have access to the search feature on the forum, so if anyone could post a link, or pictures to thier idea's/suggestions that would be great...

Thanks in advance.

[Charles Talbert]

I'm not saying you can't make this happen without issues, we have done many mods to M37's; but have always endeavored to steer clear of messing with the integrity of things like frame members. The folks at Dodge did a fabulous job designing the M37 frame as it performs like no other in severe off road applications. I've put in many hours designing other systems around it, I've never felt bad after any decision I've called in order to leave it original as far as the way it was. We have done minor additions to strengthen areas for heavy application trucks, but have not pushed it further than that. This is just my opinion, I don't care to reinvent the wheel when working with something that works as well as an M37 frame system does. They got it right the first time.

[MasterYota]

True enough Charles. I'm simply looking for more space for the steering linkage to travel in. Now that the tie rod and drag link will be infront of the axle, rather than behind and beside, I need to do something. The only options I have are to either lift the truck higher (I'd rather not) or adjust the front crossmember accordingly. I prefer cross-over steering to push-pull as it has less bind when the axle articulates.

My thought was to build a new flat crossmember and delete the massive dip in the original unit thus giving room for the linkage to operate without interference. I was leaning towards some 4x2 square tubing with flanges to bolt between the frame rails again. Plated and welded together they should provide the same or better strength. I'd rather not re-engineer the whole frame, but in this regard, my choices are limited.

I plan to hang the axle first, so that that I can mount the steering box and linkages accordingly to see exactly what needs to be done to the crossmember. I hope that good planning will prevent regrets once the hot wrench comes out!

[Gordon Maney]

Take pictures; it feels like there is an article in this....

[MasterYota]

Take pictures; it feels like there is an article in this....

Will do Gordon. I plan on taking alot of pictures during the buildup. If you spot anything of interest, just ask, and I'll send them to you with a writeup...

[Bruce in BC]

Here is one mod that might work .

http://www.powerwagonadvertiser.com/...t=5521&page=21
I am running a dana 60 in my Carryall . Yes it is cross steer and I just got it to fit . Running a saginaw box in front of the rad , like many jeeps might be worth considering . There are shots of the steering set up buried in the thread too .

Bruce

[MasterYota]

Thanks Bruce - judging from the pictures it looks like you just cut the rivets, pulled the crossmember out, and narrowed it up as needed - right? Did you cut the face off with a big bandsaw or by zip cut? Any issues with shortening it? Or removing it from the frame for surgery?

Thanks for the help - its much appreciated!

[Bruce in BC]

yep that is pretty much what I did .

Drilled out the rivets and tapped the cross member out by smacking it on one side more than the other . I used a plasma cutter and then cleaned up the edges with a grinder . Originally I left both flanges in place but I had to remove the rear one to get clearance for the steering link . Before you get started I would recommend that the motor , axle and steering box position is established first . Much easier doing it with all the parts in place and you can tweak things a bit . You may find that building a new cross member is easier than sectioning the old one .
Oh joy , I am off to a search & rescue practice .
run by a very intense woman
bruce

[lebowski]

MasterYota, are you going to run the D60 full width or trimmed 3" on the long side? Sounds interesting.

[maineSS]

Bruce-

I see you're running a reversed spring shackle- I assume it wasn't stock on the Carryall. Supposedly it helps soften the hit when you hit bumps quite noticeably- does it work that way for you? These axles are a lot of unsprung weight- every little thing helps...

[MasterYota]

MasterYota, are you going to run the D60 full width or trimmed 3" on the long side? Sounds interesting.

I'm going to run it full width. I have a set of H1 Hummer double beadlock wheels with 7" of backspace that I will use to pull the tires back under the fenders. I'm using a SRW D60 front with a 2" wheel spacer to ensure that the wheels will clear the steering linkage, but not stick out too far.

The SRW front with the 2" spacer gives me a 73" track width. Which would be the same as using the dually front hubs, and narrowing the housing 3". I think this route is cheaper, easier and less work. With this setup, according to my math, a 15" wide tire will stick out about an inch or so past the fender. My plans are to run a 38-42" tall tire. I may also end up using a narrower spacer depending on how the wheels clear the linkage.

I'll build new spring hangers outboard of the frame to match the D60 perch width. Stock GM spring hangers look as they might also work as mounts. I'm just getting ready to roll the truck into the garage to start taking measurements and begin the day-dreaming...

[lebowski]

I too had thoughts of the Humvee rims with the D60. I think the rims will retain the military look on the M37 and suit it well. I also agree your approach of using a stock width axle is more cost effective than cutting 3" off the long side. Good point on the front crossmember, something I was not aware of if going to crossover steering with the M37 frame combo. I have push/pull on my GM 1ton with frt D60. It's old school, but it seems to be ok with the limited travel suspension I have and terrrain. What type of terrain is your suspension going to be built for?

Regarding the spring hangers, there was some pics on the net where someone did this. He hung a D44 instead of a D60 though. I remember seeing it on the other board that is now gone. I"ll see if I can find the link. Please do keep us informed and updated with pics - it's something I would like to follow.

[Bruce in BC]

Reversed shackle ........

I have not got a clue how it will work on the carryall . I am still building the thing . I am running a similiar set up on my trash truck and it seems to work fine .

[maineSS]

One of the reasons folks go with modern axles is to drive at modern speeds- but hitting a bump at high speeds with 1940-style suspensions can put you in the opposite lane. Flipping the shackle allows the spring to start compressing before the chassis takes the hit- like pulling a wheelbarrow over a bump vs pushing it. I'd thought about trying it with my PW, but it's a lot of work, and I was curious to see if the benefits are worth it in real life. Radial tires did help compared to bias-ply, but the bump situation could use more work.

[MasterYota]

One of the reasons folks go with modern axles is to drive at modern speeds- but hitting a bump at high speeds with 1940-style suspensions can put you in the opposite lane. Flipping the shackle allows the spring to start compressing before the chassis takes the hit- like pulling a wheelbarrow over a bump vs pushing it. I'd thought about trying it with my PW, but it's a lot of work, and I was curious to see if the benefits are worth it in real life. Radial tires did help compared to bias-ply, but the bump situation could use more work.

Ahh....the bump... In my last M37 there was an "X" carved in the insulation foam in the artic top directly above the driver. I couldn't figure out why it was there until I hit a speed bump in a parking lot a little faster than I wanted. That spot is exactly where the drivers head contacts the roof with enough enough force to make you drive slower or install seat belts!