Got The Shaft, Vibration Gone!

[319]

Well folks, i've had a nagging vibration in my M1028A1 for some time now. Vibration would start between 50 and 55 mph. Figured it was an out of balance drive shaft, but I never suspected it was the wrong drive shaft. After doing a search on drive shafts in the CUCV forums, I discovered my drive shaft was actually for an M1008. Took the correct measurements and my slip yoke to a local builder and they whipped one up in a day. The yoke did not slide far enough into the transfer case thus causing the vibration. Took it for a spin on the freeway tonight at speeds between 50 and 65 and not the slightest issue!
Oh, by the way, I now have a good used driveshaft for an M1008 for sale.

 

[doghead]

Other than length, are they the same?

Can you post the lengths for either?

 

[319]

Other than length, are they the same?

Can you post the lengths for either?

As far as I can tell, except for the length, they are the same .

Here is what I found in the forums:

Pick-ups/chassis (NOT M1009) w/ TH400 &:
NP205 57-1/8"- 57-3/8"
NP208 54-1/4

The shop had me measure from the face of the rear yoke to the rear face of the transfer case (60-3/8") and from there they deduced that the driveshaft should be 57-1/4" from centers of u-joint to u-joint. The diameter is 4".

This company ( Dynotech Driveshaft Custom Driveshafts, High Speed Balanced built to your specifications in Steel, Aluminum and Composite Materials ) does R&D and builds for several of the auto companies and also NASCAR teams.

 

[gimpyrobb]

MMMmmmm, that sure is a pretty DS!

 

[Dave Kay]

It's a thing of beauty! And thanks for that measurement--- I'm looking to find a DS in a local yard and get it done-up proper--- just needed to confirm that magic number!

BTW: are the U-joints 1350's? And if you don't mind--- what did that baby $et you back?

 

[rnd-motorsports]

Just went out a measuerd the shaft that came in my 1028 with the famus fork truck dent and its on the money with your finding at 54 1/4 center of joint to center of joint

 

[Dave Kay]

I have another question: My M1008's DS has a definate loud vibe over 50 mph and you can see the slight forklift damage--- but is it a really bad NO-NO to be driving around on a bent DS? Like, is it going to damage seals, berings, or whatever?

As best as I can measure, my DS is approx .90-PLUS runout ('bout the thickness of a nickle) and a builder told me anything over that needs re-tubing. But--- since he did a such crumby job on my civi 1-ton DS w/center bering, I don't think he knows squat--- anybody?

 

[rnd-motorsports]

The transfer hangs off the back of the transmission at the mount so the weight and length of the transfer Plus the out of balanced drive shaft the harmonics of the drive shaft being out of balance get multiplied the seals will have a shorter life but the case of the trans will be the week point and crack at some point! A new drive shaft is allot easier to change then a broken transmission.

 

[wallew]

NAH, it just costs money to rebuild it.

As long as you don't do any damage to the transfer case, you're good.

My DS was damaged on my M1028A2 and I drove it home with a vibration at about that speed (2k miles). The teeth on the yoke were chipped and one or two were partially missing. About $400 later, she's smooth as a babies butt. I have to pay attention to my speed now, because I just don't 'feel' it anymore.

 

[Cucvnut]

I get my Dshafts made for 160 a shift including 1350's

 

[Dave Kay]

I get my Dshafts made for 160 a shift including 1350's

NO--- 160? YOU DON'T SAY...? Balancing included?

(pssst... where at?)

PM me dude!

 

[WARWAG]

I have another question: My M1008's DS has a definate loud vibe over 50 mph and you can see the slight forklift damage--- but is it a really bad NO-NO to be driving around on a bent DS? Like, is it going to damage seals, berings, or whatever?

As best as I can measure, my DS is approx .90-PLUS runout ('bout the thickness of a nickle) and a builder told me anything over that needs re-tubing. But--- since he did a such crumby job on my civi 1-ton DS w/center bering, I don't think he knows squat--- anybody?

VERY Bad! Dont do that.
There was another member who cracked his transmission driving with a bent drive shaft.

 

[319]

MMMmmmm, that sure is a pretty DS!

I know! I thought about getting two, one for the truck and one for above my fireplace!