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I just finished installing a wc51 rear axle in my m37, not quite a bolt in, some fab and machining required but what a difference! Makes me wonder why everyone doesn't do this swap, almost no transfer case noise, better acceleration it feels like a newer truck. If anyone has any questions on how to do this feel free to ask, getting the emergency brake to work took a little creative thinking.
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r.e. wc rear
Matt,
I'm currently putting a d44 front and an Eaton 52 rear in my M37. How did you choose to connect the driveshaft to the tc output?
Thanks,
Mike -
driveshaft
T Bob I had an extra passenger side output flange for the transfer case. I redrilled the emergency brake drum so the two would bolt together. you can do this by putting the drum over the driveflange and inserting shim stock in 3 or 4 evenly spaced locations between the two, I think .030 was about right. Then use a transfer punch to mark the holes and drill them out with a letter u drill and tap to 7/16 / 14 nc. Work your way up from a smaller hole and check the diameter with a dial caliper before you tap them it should measure .368 inches. loose will cause problems. buy 4 7/16/14 by 1 1/2 inch long grade eight bolts doorman Lawson, L E no Chinese junk they have to be completely threaded, no shoulder. Install these in your modified e brake drum so that the bolt heads face the transfer case and the threaded portion faces the rear of the truck. I recommend Loctite 680 green on these. Now place the e brake drum over the driver's side transfer case output. Next the drive flange and loosely install the nut. you'll see that your e brake drum doesn't line up with the brake band. Center the drum in the brake band with the bolts through the drive flange and measure the distance between the two, you'll need four spacers for this I believe mine needed to be about 5/8 inch long I can't remember for sure, I made mine from some stock in the lathe. I used hardened nuts and lock washers to secure my driveshaft, Loctite's also a good idea. If this doesn't make much sense I can send you some pictures. hope it works out, Matt.Comment
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wc rear
What was your final driveshaft angle? Thinking about putting in a cv to eliminate vibration on mine. My tcase is moved rearward 4-5 in to accomodate a 318/727 combo.Comment
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angle
my angle was a little steep, cv is a good idea. I lowered the transfer case a half inch by slotting the 2 half inch holes in the driver's side mounting bracket in a milling machine, some patience and a file will work. I also used 4 degree shims from the local speed shop between the perches and the springs. you could also remove one or two leaves from your rear spring pack to slightly lower the truck, also may help the ride quality. I'm not sure if you can have a cv driveshaft with a slip yoke, kind of seems like it'll self destruct...have you considered a 2 piece shaft with a hanger bearing in the middle?Comment
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Cv
I'm having a cv ready output flange machined to replace the stock one, then a driveline company here is SC is making a new driveshaft. 1310 cv on the tc end and 1350 at the diff to fit the Eaton. My original mock up measurements showed close to 20 degrees ds angle....too much for stock I'm afraid. They already made me a 1350 intermediate shaft.Comment
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angle
The short wheelbase on these trucks is hard to work around, it would be much easier if they were the length of an m43. short of stretching the frame, I would think lowering the suspension to decrease the angle or lowering the t case seems like the best option. I wouldn't tilt or angle the t case, might adversely affect the oil distribution. Have you considered eliminating the intermediate shaft and marrying the 727 to the t case with just a u joint in between for more length? seems like it's possible.Comment
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Intermediate shaft
Looked at that since others have done it, but I wheel a little and have seen how flexy the frame is. Worried about putting the driveline in a bind during articulation. If I was starting over I would shorten the 727 and go with a married tcase, but since I've "started over" bout three times already I better stick with a plan...;)Comment
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cv
Got the CV shaft in...man, what a difference! Now I can start chasing down all the noises I couldn't hear before....have to put in a plug for Carolina Driveline in Spartanburg,SC...great guys to work with, especially Bret.Comment
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Noise
Matt
Now that I'm running centered seems like a rattle in the tcase at certain speeds. Maybe the idler gear not having anything to do? You experience anything similar? The old whine is gone though....
MikeComment
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rattle
no new noises since the conversion, my neighbor says he can't hear it form a quarter mile away anymore.Comment
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Matthew,Originally posted by Matthew Ziegler View Post
What about the situation with the centered rear not being in line with the normally positioned NP200's center output? I have installed a WC rear in my M37 build, and wondered about that not being a problem along with the driveshaft angle.Comment
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offset driveshaft
Dave, I did notice the t case output isn't perfectly centered, as long as the u joints aren't at too great an angle or binding It's a diagonal driveshaft angle rather than the typical vertical. How'd you adapt your driveshaft to the driver's side of the t case? I kind of reinvented the wheel on mine.Comment
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As I understand things, the NP200 type transfer case was also used on the WC 63 6X6 with two rear outputs to the two rear axles. So, there is a yoke that goes in the center of the parking brake assembly, over the rear driver output. A big nut fits on here, and allows you to drive off that output.
I believe I bought mine from VPW.
This makes it an easy mod.Comment
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flange
for some reason I tend not to see the easy solutions probably a cross between being mostly german and owning a lathe... That readily available flange would've saved at least a day and three trips to fastenall.Comment
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