Front Driveline after 6.5" lift

Hey all, so this is what it looked like roughly six months ago:



Roofrack perfectly follows the angles of the body


I bought it in september completely stock. its a '91, 4.0 HO, automatic, D30 disco/D35, 126K, and awesome! The first thing i built was the roof rack. I needed to build something but hadn't settled on a plan yet.

I then started lurking forums like a cyber thief. Mainly this one and Jeepforum. So, this is what i did:
'86 waggy D44s front and rear. Fully rebuilt, nothing was reused.
Warn premium hubs.
Electric fan override power switch.
4.56s
SYE
Aussies front and rear.
IRO 6.5 long arm kit.
Tom Woods in the rear.
JKS swaybar quick discos.
315/75/16s (~35")

How she looks today:


I ran out of things to drive on to test the actual flex


So now to the problem. As you all know the front driveline already has the cardan joint. when driving around with the hubs unlocked she drives like a dream. lock the hubs in and the damn thing feels like its going to shake apart (i mean really badly) above 40MPH. I cant really change the pinion angle to point it toward the TC becuase then i get into some bad caster. I already had to adjust the top mount to get more caster so the thing behave with some respectable road manners. I would appreciate some input, opinions, other options etc... The way i see it i have 4 options.

1. take the front out, cut the knuckles off and turn them so that i can point the pinion at the TC. this is by far the least desirable option as this is my DD. It is also arguably the most difficult and would tax my abilities.

2. Lower the TC by the one inch that the IRO crossmemeber facilitates. Also, adjust the caster forward to try and find a happy medium between vibration and handling. I just don't think this will solve the problem. But, i could probably do this in an hour or so just to see.

3. Get a double cardan driveline for the front, meaning two cardan joints. One on the axle and one on the TC. This is my most preferred options, i am hoping someone on here has used a double cardan driveline before and has good things to say about them. ??

4. Suck it up, only use 4 wheel drive below 35MPH and deal with turning the hubs in and out every time i want to go faster. Main problem with this is i dont even have to be in 4 wheel drive, i just have to have the hubs locked and the vibration is terrible.

Any thoughts?

General wisdom is to compromise the caster angle and pinion angle until the vibes go away. If you have hubs, unless you are doing go-fast in the dirt, why would you lock the hubs unless you were offroad and probably not going faster than 35?

Well you should have started with a HP44 instead! but really why do you need them locked for driving around? and if it is because you do go fast and need 4x4 well then maybe you do need a HP axle..

X3 on why locking for the road?? That's the benefit of locking hubs, is it not?

Driving with the hubs locked on dry pavement is not a good thing with an NP231. If your tires are the least bit different in air pressure or wear, the driveline will bind. Turning will be difficult at best. In short unless you are running an NP242, never drive in 4wd on dry pavement.

And we assume he's not running the 242 as he mentioned the SYE.

do you have to go that fast in 4wd ever? if it snows here and i have to use 4wd im going slow, otherwise im in 2wd

SolarBell said:

General wisdom is to compromise the caster angle and pinion angle until the vibes go away. If you have hubs, unless you are doing go-fast in the dirt, why would you lock the hubs unless you were offroad and probably not going faster than 35?

Click to expand...

This is basically option 2.

whitexj98 said:

Well you should have started with a HP44 instead! but really why do you need them locked for driving around? and if it is because you do go fast and need 4x4 well then maybe you do need a HP axle..

Click to expand...

I should have yes, but this is what i was able to find when i was looking. I was impatient at the time and obviously i am paying for it now.

DeftwillP said:

And we assume he's not running the 242 as he mentioned the SYE.

Click to expand...

Correct, it is a 231.

XJ longhouse said:

do you have to go that fast in 4wd ever? if it snows here and i have to use 4wd im going slow, otherwise im in 2wd

Click to expand...

Some of the trails around here have nice (smooth) straight stretches that go for miles inbetween the "fun" parts of the trail. It would be nice to go out wheeling, lock the hubs in once on the trail and be able to switch from 2x to 4x as necessary without having to lock and unlock the hubs mulitple times. That is really what i am trying to get.

So has no one used a double cardan joint driveline that is willing to chime in?

Thanks.

how about rebuilding your damned driveshaft? most OEM front driveshafts that i have seen were worn out, but because they have very little angle on them you don't see vibes from them. lift the rig and its like world war 3 down there.

I have 8" lift and do 75 mph with the front hubs locked (in 2wd of course) with no vibes. driveshaft is from JE Reel and about two years old.

cal said:

how about rebuilding your damned driveshaft? most OEM front driveshafts that i have seen were worn out, but because they have very little angle on them you don't see vibes from them. lift the rig and its like world war 3 down there.

I have 8" lift and do 75 mph with the front hubs locked (in 2wd of course) with no vibes. driveshaft is from JE Reel and about two years old.

Click to expand...

The D44 was longer than the D30 so i had to have the shaft shortened. It was checked out at the same time. It should be in good condition.

You ever rotate your knuckles? Are you running a lot or a little caster?

Thanks.