can sagging rear cause death wobble/vibes?

Last few times I've driven the heep (all stock drivetrain, 4.0/AW4/231/D30/D35) I've felt what feels like the descriptions I've heard of DW, but it's not that bad and seems to be a higher frequency than what I'd expect of something called "wobble." Basically I'll be driving along at about 60-70 MPH and I'll start feeling a vibration in the steering wheel, and if I lift off the gas it'll get real bad and won't go away until I slow below 40ish or so. Doesn't happen all the time only every now and then. Feels like bad tires but you'd think it'd either happen all the time or only when the tires are cold and square. (My tires are questionable though - good tread but cheap.)

Should I take it to a good shop and ask them to road force balance my fronts and check my bushings (I can't see a problem) or should I replace the rear springs first and see what happens? I need to do the springs anyway, I am probably going to order them this weekend.

I'd like to get this sorted as I have found myself driving it more lately as I've been needing to move stuff around and also it's nicer now that I've fixed a couple other things that were bothering me.

No, but bad balance and worn front end can. Death wobble is when the front end resonates, a sloppy joint allows this to happen. The degree to which this occurs depends on a lot of things. I'm betting your front suspension bushings are as original as the leaf springs. Track bar, control arms, ball joints, and steering are all suspect.

Definitely get that Road Force balance done, go from there.

Well I drove it two long runs yesterday. One with my toolbox and other tools (probably grossly overloaded.). First run - massive vibes @ 60ish. 2nd run - slight vibration but kicked ass at 75+ the whole way.

When you experience death wobble, you WILL know it. You will likely have to go home and clean your shorts.

How many miles since the tires were professionally balanced. They do go out of balance as the wear,
Ron

Not that many - maybe 7k tops. Tires still look brand new, but I'm not sure that they aren't a part of the problem.

Digger87xj said:

When you experience death wobble, you WILL know it. You will likely have to go home and clean your shorts.

Click to expand...

x2 you will have no choice other than to pull over instantly, not sure if you are talking about driveline vibes or DW.

Update: been just riding to the shop with the owner and the XJ slept there all week. FINALLY got a chance to rack it, balance the tires (old school spin balance, not road force) and pack up my tools. Drove home last night on the Beltway, got it up to around 65-70 no problem. Still a little vibe but one of the fronts was visibly square, wish I had $$ for some Michelins. Still bitter that I let a brand new set of AT2s go with my POS F*rd pickup because at the time I didn't know anyone that had a tire machine that would let me have shop privileges, would have cost about $240 to swap tires between two vehicles.