Drive shaft questions (1 Viewer)

[Rackety]

I've recently obtained this '72 40-series. It wasn't running when I got it. I've rectified that, and am now starting to chip away at the other issues necessary to get it back on the road.

I'm not terribly experienced with auto-mechanics so please feel free to correct any assumptions I've made or incorrect terminology I've used here. Learning as I go.

The truck has about 6" of overall lift.

Rear drive shaft: missing!
I have two replacements, neither are the correct length and will need to be modified. The rear suspension is spring-over-axle and when that was done the axle was rotated so the drive shaft flange is pointing towards the transfer case. A friend stopped by the other day and said he would add shims to rotate it back down to level. However I have read on this forum that others have added shims to rotate the flange toward the t-case...so confused. With the upward rotation I have currently the fluid port on the back of the pumpkin is angled kind of far down and would be difficult to fill, but other than that I would have thought the rotation toward the t-case was a good thing. Please advise!

Front drive shaft: present but too short?

 

[Rackety]

...continued

The front drive shaft seems (possibly) to be too short. It's hard to see from the photos, but I can clearly see the splines in the gap between the components. So the question here is - does this drive shaft need to be lengthened?

 

[charliemeyer007]

What engine/tranny/transfer is in it? There is a proper range of u joint articulation too much or too little causes problems. Not a SOA guy

 

[aztoyman]

Here's some good info. Driveline Geometry 101 - https://4xshaft.com/blogs/general-tech-info-articles/driveshaft-angles?srsltid=AfmBOoqPE-1WDKZ7pMG5VBVHfot8XP62Tm0HU77ZIfikDXv3VbJGBDwJ

The front is almost at the point of coming apart so it's not long enough.

 

[pb4ugo]

The way the rear pinion is pointed at the tcases rear output, you will need a double cardin joint driveshaft made for it. You'll should also raise the gear lube fill hole so it holds more fluid and will lubricate the pinion bearings. Your frt looks like it's setup with a rear shackles. You'll likely need a double cardin joint too. You will need a longer slip joint also. Tom Woods driveshafts website has good tutorials on driveshaft set ups.

 

[Rackety]

What engine/tranny/transfer is in it? There is a proper range of u joint articulation too much or too little causes problems. Not a SOA guy

Original F engine, 4-spd tranny (added later), t-case as yet unknown

 

[Rackety]

The way the rear pinion is pointed at the tcases rear output, you will need a double cardin joint driveshaft made for it. You'll should also raise the gear lube fill hole so it holds more fluid and will lubricate the pinion bearings. Your frt looks like it's setup with a rear shackles. You'll likely need a double cardin joint too. You will need a longer slip joint also. Tom Woods driveshafts website has good tutorials on driveshaft set ups.

raise the gear lube fill hole - just drill and tap a new one higher up?
thanks for the Tom Woods recommendation too

 

[Rackety]

Here's some good info. Driveline Geometry 101 - https://4xshaft.com/blogs/general-tech-info-articles/driveshaft-angles?srsltid=AfmBOoqPE-1WDKZ7pMG5VBVHfot8XP62Tm0HU77ZIfikDXv3VbJGBDwJ

The front is almost at the point of coming apart so it's not long enough.

thanks!

 

[peesalot]

Your pinion is rotated too far up IMO, as your friend suggested some 2 deg shims wouldnt hurt. I think I'd cut off the triple shock mounts as well.
That front shaft is too short, may work in rear. The driveline tube/slip should be about half way where it shows at the end of the slip yoke. FWIW the splines come out past that shield a bit but not much. I have seen guys run them like yours in the pic.

 

[pb4ugo]

Pardon my chicken scratch. You can cut a rectangle in the flat of the cover. Cut just below the fill hole and slightly wider than the hole and as high as you want the fill hole. Once the rectangle is cut out, flip it over and weld it back into the cover.

 

[charliemeyer007]

4 sp Tranny is longer than OEM 3sp. Maybe you have the 3sp's transfer with the adapter shaft/gear to work on the 4sp tranny. You get about 1/2 gear lower ration in 4L 1st gear.

 

[WarDamnEagle]

Lots of good suggestions but let me ask, do you want that much lift?

 

[pb4ugo]

I was just looking at those springs. Are they the old dreaded 3 leaf stiff ass 4" springs from back in the 80's?
If so, I'd scrap'm. If thats what they are they'll have no flex.

 

[peesalot]

Those springs are awful. Terrain Tamers or Dobinsons for the win.

 

[lcwizard]

Too many potential issues with this setup to assess here. It looks like you're in Alaska. Look up Mark Whatley in Wasilla
at Cruisers Only. He's got decades of experience with Cruisers and can give you a first hand evaluation.
Not positive but I think he goes by @Mark W on MUD

 

[Rackety]

Pardon my chicken scratch. You can cut a rectangle in the flat of the cover. Cut just below the fill hole and slightly wider than the hole and as high as you want the fill hole. Once the rectangle is cut out, flip it over and weld it back into the cover.

View attachment 3875735

great suggestion, thanks

 

[Rackety]

Lots of good suggestions but let me ask, do you want that much lift?

I certainly do not! It's on 39" tires right now but I will probably settle on 33s down the road.

I don't actually have any idea where to begin on lowering it though. I've added some pics of front suspension as well - feel free to suggest where to start on lowering this back down a bit (4" overall)? The front shackles are 5.5", the rear ones 4.5".

Front:

Rear:

Regarding the springs - no idea about their vintage. Is there a way to identify them?

Yes, I'm in Alaska. I'm familiar with Mark Whatley, by reputation anyway. Thanks for the recommendation.

 

[Rackety]

Also, here's the rig itself, for reference.

 

[WarDamnEagle]

I'm a little confused by the pictures. Is it spring under (the axles) in the front and spring over in the rear? If I was serious about making it drivable then I would probably settle on a 2" to 3" spring and shock kit (OME, Dobinson, etc.) and convert everything back to spring under......but that isn't necessarily cheap.

 

[Rackety]

@WarDamnEagle you're correct. Spring under in front, over in back. Shackles at the rear in both situations.

I'm pretty certain but just want to verify - do the suspension work (if I decide to go that route) before having drive shafts altered, right?