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Rear shackle lift on MJ

2K views 7 replies 4 participants last post by  cj7xjmj 
#1 ·
I'm a newbie at this, so bear with me. I have a longbed Comanche with pathetically sagging SUA rear springs, and a possible home brew two or three inch lift in front (I just bought it and haven't sorted it all out yet).

I want to rebuild the back and get it safe again, but I also need about two or three inches of lift. I was thinking about pulling out the crappy leafs, and replacing them with newer Comanche leaves, adding an add-a-leaf, and a rear shackle.

I am only looking for about three inches of lift, some weight carrying capacity (Not F-350 country, just enough to be useful) and leaving it SUA until I can figure out how much of a lift I really want for it.

Has anyone done this? Are boomerang shackles any good? Does anyone make an add-a-leaf for this? What will this do to my driveshaft and pinion angle?

I'm not looking for a radical lift, just something to level it out and be safe.
 
#3 ·
Sorry, forgot to mention that the shakle will tilt the pinion up slightly and that should help with vibes. RRO (shakle place) also offers degreed shims fo rthe rear axle that will help the angle as well. I would say (off thetop of my head) that a set of 4* shims and the shakle will give you no vibes at 3-3.5" of lift. the D44 is supposed to have a shorter pinion than the 8.25 axle, so the DS will be longer and will also help decrease vibes.













 
#4 ·
You might want to check with other companies asking them if they have a suitable shckle that cn be used. I think the shackle I got which has an insane amount of lift (83/4)" eye to eye) came from a ford or a Toyota, i can not verify this, but I have been unable to locate it anywhere else.

AS for springs, good luck. as far as I can tell no one make a lift spring pack for the comanche. They all require the SOA conversion, or involve the use of shackles, blocks, or AAL.

Ballo, you are 100% right about the long shackles causing vibes. Thats why I had to do a SYE on my MJ. That was one of the best mods I ever did though :D


Patrick
 
#5 ·
hey stephen whast up !

i would go SOA if your comfortable with welding and pinion angle fiding, also if you go SOA will you need an SYE?
 
#6 ·
cj7xjmj said:
Ballo, you are 100% right about the long shackles causing vibes. Thats why I had to do a SYE on my MJ. That was one of the best mods I ever did though :D
Patrick
No, the long shakles will help the vibe situation becasue it will tilt the pinion up and improve the angles between the TC yoke and the pinion yoke.

The soa's are a great way to gain quite a bit of lift. About the only thing to worry about is axle wrap, but that is rarely a problem if the leaf packs are in good shape.
 
#7 ·
Thanks for the help. It sounds like the toughest part will be just finding new leafs.

Correct me if I'm wrong, but with the stock yokes and driveshafts, I basically want to keep the pinion angle and TC output parallel, right? I would only want the pinion shimmed in line with the driveshaft if I go with a CV type shaft (which will happen eventully when I've figured out my 5.5 lift down the road) right?
 
#8 ·
The t-case yoke and the pinion yoke shopuld be within a degrree or 2 using an angle finder. When I did my SOA my axle rotated towrds the pinion big time, and my pinion and driveshaft were just about straight, putting the top yoke in a slight bind, causing the vibes I was experiencing. I was told that I could have changed my yoke at the t-case to a YJ yoke and it would have eliminated part of my problems. I have been told that the YJ yoke is longer.



Patrick
 
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