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m37 frame strength

Posted: Thu Oct 12, 2017 3:48 am
by 52PLOWERWAGON
would a stock m37 frame handle the excessive amount of torque a 6bt cummins puts out ?
or would I need to add more crossmembers to it and plate it ?

I have an engine lined up for the m , it shall be revived ....................... again, but this time with no nonsense

Re: m37 frame strength

Posted: Thu Oct 12, 2017 6:39 am
by W_A_Watson_II
All depends on how you use it. A Stock frame will crack under any engine when used for extreme off road when flexing.

Re: m37 frame strength

Posted: Thu Oct 12, 2017 12:54 pm
by RMS
2x on that !

the military cheeped out when they welded the xmember to the top frame rail flange. wc's and ffpw's were bolted

Re: m37 frame strength

Posted: Sat Oct 14, 2017 1:19 pm
by m-37Bruce
If you can do it, you certainly should, weight plus torque could make things move more than their supposed to.

Re: m37 frame strength

Posted: Mon Oct 16, 2017 8:41 pm
by PoW
I ran mine hard for over 250K miles on & off road, never had a frame problem.

In those 30 years, I went through 13 sets of rear ring/pinion: the power of my Detroit ate the Formate treated teeth through to razor blades. So will your Cummins W/overdrive @ 65 mph

Btw, that was with complete NOS drop-ins (back when you could buy them).

I recommend setting up a Dana 80 in 4.89:1 with M37 hubs for the rear.

PoW

Re: m37 frame strength

Posted: Tue Oct 17, 2017 7:19 am
by Kaegi
PoW wrote:I ran mine hard for over 250K miles on & off road, never had a frame problem.

In those 30 years, I went through 13 sets of rear ring/pinion: the power of my Detroit ate the Formate treated teeth through to razor blades. So will your Cummins W/overdrive @ 65 mph

Btw, that was with complete NOS drop-ins (back when you could buy them).

I recommend setting up a Dana 80 in 4.89:1 with M37 hubs for the rear.

PoW
I am surprised to read that you fried the teeth. maybe the new production gears are tougher? I have never had one fail but mine were mostly flatheads with cams and raised compression. 1 v8 truck. all of mine were 5.83s

Re: m37 frame strength

Posted: Tue Oct 17, 2017 7:28 am
by 52PLOWERWAGON
most likely I would run axles from an m135 deuce so hopefully i'll not have axle issues

Re: m37 frame strength

Posted: Tue Oct 17, 2017 9:22 am
by 06boblee
PoW wrote:I ran mine hard for over 250K miles on & off road, never had a frame problem.



I recommend setting up a Dana 80 in 4.89:1 with M37 hubs for the rear.

PoW
Are you talking about a custom built Dana 80- or will the M37 hubs fit one?? Will the M37 hub fit any other axle without mods?

Re: m37 frame strength

Posted: Tue Oct 17, 2017 9:14 pm
by PoW
That would be custom. Nobody makes off the shelf things that I need.

All the rears I ruined were from running around 70 with standard gear lube. Pulling heavy trailers, that sort of thing.

Those old gearsets just weren't meant to spin that fast, no time to cool before contact again.

Synthetics might help, but I'm not doing that drill this time.

PoW

Re: m37 frame strength

Posted: Tue Oct 17, 2017 9:24 pm
by PoW
52PLOWERWAGON wrote:most likely I would run axles from an m135 deuce so hopefully i'll not have axle issues
Theys too wide..will look really odd. Even lower speeds, too.

You can cut them, reweld for proper distance, but getting someone with a forge to upset the axle shaft ends, then re-spline is hard to do.

PoW

Re: m37 frame strength

Posted: Tue Oct 17, 2017 10:05 pm
by RMS
2xs on the diffs cant take the heat
PoW wrote:I ran mine hard for over 250K miles on & off road, never had a frame problem.

PoW
majority of the trucks ive seen, have a crack on the top flange of the drivers side frame rail at a large undercut(on the end of the weld) were the xmember is joined.

the truck pictured below has had 6 cracks on the 4 welds that attach the x members. ....and im still running a flat head. :P

Re: m37 frame strength

Posted: Wed Oct 18, 2017 6:20 am
by PoW
That problem usually stems from loose steering components coupled with lumpy or out-of-balance tires.

PoW

Re: m37 frame strength

Posted: Wed Oct 18, 2017 7:36 pm
by 06boblee
Is it the crossmember that cracks, or the frame rail? The crossmember goes all the way under the frame rail- would putting a bolt thru them help?

Re: m37 frame strength

Posted: Thu Oct 19, 2017 6:10 am
by rickf
Bolted only frames don't crack because the bolts (or rivets) allow for some movement between the frame and cross member. When the cross member is welded there is no movement and something has to give and it is 90% of the time the frame rail next to the weld. Putting bolts in a welded cross member will do no good unless you eliminate the weld.

Re: m37 frame strength

Posted: Thu Oct 19, 2017 5:07 pm
by 06boblee
rickf wrote:Bolted only frames don't crack because the bolts (or rivets) allow for some movement between the frame and cross member. When the cross member is welded there is no movement and something has to give and it is 90% of the time the frame rail next to the weld. Putting bolts in a welded cross member will do no good unless you eliminate the weld.
So- if the weld fails on the frame rail, wouldn't a bolt thru the rail and the crossmember maintain strength (after the weld fails?).