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Backwards Math - How Much Lift?


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Long story short. I think my MJ got monkeyed with too much through the several hands that have been on it through the years. The other day we went for a trip into town where I took a reasonable turn that caused some lean in the suspension and next thing we heard a nasty squeal as my rear end locked up and the driveshaft was found to be spat out from the tcase. Spring wrap may have had some involvement but no apparent damage seen.

This is what I know: SOA, 7 leafs in the pack and those are definitely not stock shackles. The front I think are 6.5inch springs with adjustable high clearance arms but even then I am just guessing.

Measuring and poor memory recalls its roughly 7-8inches from top of tire to bottom of factory flare at the front (left sits 1.75inch lower than right) and at back its something like 11-13inches from top of tire to bottom of factory flare (again sits 1.75inches lower on left).

It sat near 2.5 years since the last lift was done so some awkward settling may have occured....

How do I figure this out oh great MJ Gurus....

rejy6y5u.jpg

When the truck broke down good side profile on 285-75-16 mud kings. Cop thought it was a Toyota unknown according to the dispatch for tow truck. Driveshaft wired up looks like a dogs uknowwhat.... 

 

pe9e3ybu.jpg

Shackle definitely not stock

 

ugaby5aj.jpg

SOA D35 7-leaf pack unknown

 

ududeqeg.jpg

Just another shot of the rear suspension setup 

So to recap, how much lift do you think I have and what would have caused the truck to lock up the rear and spit out its drive-shaft

Thanks for your help folks :)

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I'm sure someone else will chime in with the stock measurements, but measure from the centerline of the wheel to the fender flare.  Measuring from the tire won't tell you anything, since the tires aren't a stock size.

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Your drive shaft is too short. It either needs to be lengthened by a shop for more slip yoke spline engagement, or you can replace the slip yoke with a longer GM yoke.

 

$_57.JPG

 

http://www.ebay.com/itm/GM-Turbo-350-Extra-Long-Racing-Slip-Yoke-700R4-7-5-1310-Style-Precision-369-/251547475996?pt=Motors_Car_Truck_Parts_Accessories&hash=item3a9165e01c&vxp=mtr

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That might be a great suggestion! So if I'm running ax4/NP207 what specs should I be looking for? Is the yoke you linked the correct one?

 

 

Your drive shaft is too short. It either needs to be lengthened by a shop for more slip yoke spline engagement, or you can replace the slip yoke with a longer GM yoke.

 

$_57.JPG

 

http://www.ebay.com/itm/GM-Turbo-350-Extra-Long-Racing-Slip-Yoke-700R4-7-5-1310-Style-Precision-369-/251547475996?pt=Motors_Car_Truck_Parts_Accessories&hash=item3a9165e01c&vxp=mtr

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This yoke works fine w. the 231 and 242 cases, but am not sure of the output shaft spline count on the 207. Did not notice you had an 86. Since the drive shaft is out, count the internal splines on the yoke.

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Just a note on your rear springs.

 

It looks like the originals are the main leaf, 4th from top, 6th from top (just above the over load)  and over load leaf. The other 3 in between are bastards out of one or more other vehicles.

 

The shackles are definitely not original and seem to be a few inches longer than the stock ones.

 

If the front is 6.5", the rear should look better with the bastards taken out.

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Thanks for identifying that for me :)

 

If the front is 6.5", the rear should look better with the bastards taken out.

Would it be better to swap back the shackles to a shorter length vs undoing the pack?

 

What's the advantage of each shackle vs leafs?

 

The pack is actually not clipped together it seems (going to have to fix that) so labour wise I guess it won't make a difference on which part of the rear to swap but strength wise maybe? What about hinge point?.... still trying to figure out what caused the drive shaft to pull out it wasn't the first run the truck had at that height.

 

 

Thanks

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Well at least I figured out what caused the rear to lock up and pull out the drive shaft. Apparently it was without lube..... but never any evidence of leaking so who knew to check?

 

Killed a beautiful D44 (posi?)... ha and I was thinking I had a 35 :(

 

vu7ure5e.jpg

 

Picking up an 8.8 tomorrow. Might think about rebuilding the 44 but too cheap.

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Taking the extra leafs out of the leaf, pack should drop it down some to where the drive shaft might stay in. Going back to stock shackles will change the pinion angle, and because of that, despite it dropping the rear down some, will actually pull the shaft out more than it already is.

 

Don't know how the length of the nose of an 8.8 with a 1310 adapter would measure compared to the nose of a D44. You will most likely need wheel spacers with the 8.8 to keep your tires away from the inside wall of the fenders. With the wide @$$ of our trucks, IMO even with the stock axle you need wheel spacers to make it look right.

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It spat out the shaft on the road. Pics ares on the driveway. I'm going to do a full fluids reset before driving it again.

 

My luck is as good as it is bad. The d44 can be rebuilt I only chewed the teeth of the crown and pinion gears and 3.55 are easy finds. I'll likely have to trade a truck detail case of brew and food for the install but I'm cool with that. And it's cheaper than setting up an 8.8 with new brakes etc

 

The shackles were put in after the axle was set up so the angles should improve if they are removed and balanced with 4.5" springs vs the 6.5" in front now.

 

Thoughts?

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