Mod Coming--Slee Differential Drop: (1 Viewer)

[ShottsUZJ100]

This is a mod that was designed originally by Doron Strassman (Cruiser99) of Tucson, AZ. In my opinion it is ESSENTIAL that it be done on ANY lifted IFS 100. This mod accomplishes 2 things:

1. It allows for a one-inch suspension lift with no effect on stock CV-angles and/or up and down travels, therefore prolonging life to the joints and/or boots.

2. For those who will change the CV angles in order to gain even more lift, it allows for an extra inch lift at the same CV angle in comparison to not doing the mod. In other words, even at my lift height of 2.75-inches (1.25-inch T-Bar twist, 0.5 inch stiffer T-Bar upgrade and 1-inch Diff Drop) my CV-angles are only increased to the 1.25 inch over stock angle. I get another 1/2 inch by the new T-Bars and another inch by the diff drop. Plus, my down travel is increased back one-inch toward stock which improves my ride. In fact, without this mod, at my lift height, I'd have little down travel and that's not good.

No matter how you lift your 100 you benefit by doing this mod. Now, with Slee's "no cutting option" (under $200), it's a MUST DO FOR ALL! I have 80K of VERY HARD off-roading miles on my 100, most with 35's and almost 3-inches lift up front and an occassional locked front locker.......CV joints still good.

I began this thread for 2 reasons:

1. To again thank Doron for coming up with this design and sharing it with me so I could run 35's for all this time.

2. To direct everyone to a source for a CRITICAL bolt-on upgrade....Slee Off-Road. Hopefully Christo will sell a bunch of these!

 

[ShottsUZJ100]

AUGIE ASKED: This does not make any sense. The drop crosmember only alter the position of the diff with no effect what so ever to the suspension. I highly doubt the crosmember got anything to do with the lift.

Did you get any noise from the differential hitting the crossmember? The way you do it is by lowering the bracket but reducing the clearance between the diff to the crossmember. The rubber mount would flex a little bit and it migh cause the diff to hit the crossmember.

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AUGIE: When you lift the front end you crank/turn the T-bars which extends the A-arms down and that lifts the truck. Doing this reduces your suspensions DOWN travel and increases it's UP travel from it's "idle" position. If you crank, or lift the front too much, then you have little or no down travel left over. That's bad. Shocks bottom out over rocks and holes, your on-road cornering is more dangerous as you can lift wheels from the ground because there's no droop, and basically your ride stinks. Lastly, the more you reduce your DOWN travel the more force it takes to reach your UP travel limit because you have to twist those T-bars much more than normal in order to reach the limit of the suspension.

By lowering the diff an inch (max without MAJOR other mods), you regain that inch in down travel because you've reduced your CV joint angles toward the stock position. You can use this inch to either:

*Improve on your ride and CV-joint angle.
*Increase lift by an inch.

There is no noise, no risks, everything rides as new and untouched if kept to that one-inch lowering design. I chose to re-tune my lift to almost 3-inches so I could fit 35's. I'd guess most would stick to a 2-inch lift overall, do the diff mod to keep everything as close to stock as possible, and still run 33's. (???)

 

[ShottsUZJ100]

Yes Christo, OVERALL travel is the same, though how much UP and how much DOWN travel you have is effected and that really can drastically change your entire ride. You didn't have to deal with this much on your LX because of those shocks. As you know though on a 100, if you go to 3-inches, even wth the diff mod, you have little down travel (droop) left.

 

[sleeoffroad]

Yes, but the downtravel is limited by the shocks and not the diff. Even if you remove the shock, the limiting factor is going to be the steering and the ball joints in the A arms.

So lowering the diff is not going to change that. The CV's are not hanging uo the suspension.

 

[ShottsUZJ100]

Yes, I know the shocks limit the down travel....though the straighter your A-arms are the more down FROM vehicle resting height they have to go before they bottom.

Doron proved this to me. When he had his T-bars cranked to a 3-inch lift, his shocks were bottoming out non-stop in the dirt. He lessened his lift by about an inch and he gained a much better ride because the wheel/shock/whatever had more droop and therefore the wheels were kept on the ground much more. Make sense?

Signed,
Bad In English

 

[Landpimp]

OK, but droping the crossmember and diff BY ITSELF(no cranking torsion bars or anything else), will not give any lift...........correct?

 

[ShottsUZJ100]

Correct......no lift is gained by doing the mod. Even modest lifts (1-2 inches) effect drive quality on a torsion bar IFS front end. Doing this mod puts things back to (or closer to) stock postiioning. There is every reason to do this mod and none against it (well, you wouldn't want to do it to a non-lifted truck).

 

[ryanjl]

Correct......no lift is gained by doing the mod.

even at my lift height of 2.75-inches (1.25-inch T-Bar twist, 0.5 inch stiffer T-Bar upgrade and 1-inch Diff Drop)

These two quotes don't quite jive, then. Is there something I'm missing?


I understand how the dropped diff is necessary both for CV angles and to return the wheels (in their stagnant position) more toward the center of their travel, but I don't see how you used the 1" diff drop in calculating your total lift.

The only thing I can think of is that by dropping the diff, the torsion bars are free to exert a little more downforce, thus allowing them to create more lift. But that's just pulled out of my arse.

 

[ShottsUZJ100]

You're right-on SHOCKER! One gains the lift by cranking the T-bars. At about 2-inches you've got very little down-travel left because the A-arms are pointing down and the shock is too far extended. The rides suckaroos (and can be dangerous if you drive like me on-road). So yes...then by dropping the diff, you're back a ways toward stock so you can then re-crank those T-bars for even more lift.

AUGIE: This is what I meant by travel being effected. The more you lift the 100 by cranking the T-Bars, the lower your A-arm goes and the more the shock extends itself. The longer the shock is extended to arrive at your lift hieght, the less it has left for down travel, to soak up bumps, and keep the wheels on the ground. Then, going the other way, the more your shock is extended at your static lift height, the farther it has to travel upward before you reach that limit. This makes the T-bar OVERtwist itself and that last bit is at a VERY high spring rate therefore fighting full flex. Not good on the bar and doesn't flex as "easy" in the twisties.

 

[sleeoffroad]

You're right-on SHOCKER! One gains the lift by cranking the T-bars. At about 2-inches you've got very little down-travel left because the A-arms are pointing down and the shock is too far extended.

This part is right,

So yes...then by dropping the diff, you're back a ways toward stock so you can then re-crank those T-bars for even more lift.

This is not right in terms of travel. Dropping the diff does not change the position of the suspension parts one bit. All it does is drop the third member down and reduce the angles of the side shafts from the third member to the hub.

AUGIE: This is what I meant by travel being effected. The more you lift the 100 by cranking the T-Bars, the lower your A-arm goes and the more the shock extends itself. The longer the shock is extended to arrive at your lift hieght, the less it has left for down travel, to soak up bumps, and keep the wheels on the ground.

Then, going the other way, the more your shock is extended at your static lift height, the farther it has to travel upward before you reach that limit. This makes the T-bar OVERtwist itself and that last bit is at a VERY high spring rate therefore fighting full flex. Not good on the bar and doesn't flex as "easy" in the twisties.

The Torsion bar mounts in the front is not attached to the diff part at all. Refer back to the pictures in the other tread.

 

[clownmidget]

Christo, with all this "lift" action on the 100/470 looks like you'll need to add an "IFS for dummies" section to your site...

 

[ShottsUZJ100]

Christo: You win! I just looked under my 100 and remembered what Doron told me before. Yes, the T-Bar position determines how much lift vs up/down travel ratio you get. Dropping the diff improves CV angles though does not change the up to down travel amounts. Yes. Got it. Still have to do it for CV integrity and extra lift.

 

[Augie]

Yes. Got it. Still have to do it for CV integrity and extra lift.

No you still dont get it

 

[ShottsUZJ100]

Ya, I got it. The "extra lift" statement holds true. You go up almost 3-inches like myself without dropping the diff and you're asking for trouble. J

 

[Jim_Chow]

What's wrong with merely doing a 1" body lift up front and tapering the lift blocks so a spring lift can be used in the rear? Yeah, you need to watch the radiator fan and end up w/ a gap between the bullbar and body, but it's only 1 inch, and you don't affect the front cv angles.

--Jim

 

[ShottsUZJ100]

On a Jeep maybe James. Not on a mega$$$ truck. (Unless I go 6-inch body lift and 40-inchers )