Weirdprob.- sliding off throttle (1 Viewer)

[skidooman]

So I have an odd problem, or what I think is an odd problem, maybe its just an AWD SUV issue, but I don't think so. I am not new to snow or offroad driving, I have been behind the wheel of something since I was about 5. I am not a professional driver, but I do have some skill, so its not just me being a derp.
A little background on the vehicle. 96, 224 miles, not triple locked, 4" slee springs, Bilstein shocks, worn out suspension bushings, 315/75R16 Cooper STT pro tires, stock gears, Dobinson rear adj track bar, new ujoints all the way around.
Now my issue...
If I am in the snow, or higher speed in a loose terrain(gravel) and off the throttle, the rear end tries to come around on me. I can steer into it and get on the throttle and it will straighten out, but if I am not paying attention it can get spooky in a hurry. It feels like I am pulling the ebrake like we used to in HS in our s***box fwd cars. I have checked the linkage on my ebrake(which I never use), they are against the stops on the open direction. I haven't pulled them apart yet though, could they be applying pressure even with linkage not pulling on them?? When I have had the rear end off the ground rotating tires and such I have spun them and they don't feel like they are binding in any way. I do get s*** mileage, around 11.5+- which seems pretty normal from what I have read. I don't have any odd noises or bad driving manners, except the one in question.
Has anyone dealt with the same or something similar? Maybe a direction to look? I am at a loss, and

it is bad enough I wont drive it on the highway in the snow and I wont let my wife drive it in the snow at all, so any help would be appreciated.​

 

[ppc]

What do you mean by "off throttle"? Is this immediately as you come off the throlle experiencing engine braking or coasting?

Have you tried locking or unlocking the CDL in those conditions? Have you determined if the viscous coupler is working properly?

 

[richardlillard1]

What kind of shape are the upper control arm bushings? It’s been my experience that the truck tends to drive very squierrly if the rear uppers are shot.

 

[voodu3]

You might look into raising your rear panhard bracket. I got one from @Delta VS and the rearend stability is much improved.

 

[FJBen]

What caster correction do you have?
How about the toe settings on alignment?
the worn suspension bushings can definitely cause weird things to happen when power transfers on and off.
Also which bilsteins? Are they valved correctly for the 80?
do you have sway bars or did you take those off?

 

[skidooman]

What do you mean by "off throttle"? Is this immediately as you come off the throlle experiencing engine braking or coasting?

Have you tried locking or unlocking the CDL in those conditions? Have you determined if the viscous coupler is working properly?

Anytime my foot is off the throttle, whether I just pull it off or if I've been coasting, such as going down a hill.

What kind of shape are the upper control arm bushings? It’s been my experience that the truck tends to drive very squierrly if the rear uppers are shot.

They're all fairly worn, except the rear pan hard and the front control arms.

You might look into raising your rear panhard bracket. I got one from @Delta VS and the rearend stability is much improved.

I've seen their bracket, and all the great reviews on it. Great timing, they released it about a month after I bought my dobinson adj rear.

 

[skidooman]

What caster correction do you have?
How about the toe settings on alignment?
the worn suspension bushings can definitely cause weird things to happen when power transfers on and off.
Also which bilsteins? Are they valved correctly for the 80?
do you have sway bars or did you take those off?

I bought this thing 3 years ago, and these things were on it when I got it. Owner had 0 clue about any of it, he had only had it about a year. Caster correction is the yellow OME bushings. I don't know which bilsteins or what the valving is. I can try to get some part numbers off them. I have never had it on a rack, other than the issue stated above this thing drives beautifully. Like 80mph with one finger on the wheel. Tires aren't wearing funny either.

 

[BILT4ME]

I bought this thing 3 years ago, and these things were on it when I got it. Owner had 0 clue about any of it, he had only had it about a year. Caster correction is the yellow OME bushings. I don't know which bilsteins or what the valving is. I can try to get some part numbers off them. I have never had it on a rack, other than the issue stated above this thing drives beautifully. Like 80mph with one finger on the wheel. Tires aren't wearing funny either.

Does this have a part time 2WD kit in it and locking front hubs?

Otherwise, the only other thing would be the bushings in the rear control arms.

 

[LandLocked93]

Rear proportioning valve is activating in lift-throttle situations? A 4" lift coupled with worn out susp bushes...sure.

 

[voodu3]

Anytime my foot is off the throttle, whether I just pull it off or if I've been coasting, such as going down a hill.



They're all fairly worn, except the rear pan hard and the front control arms.



I've seen their bracket, and all the great reviews on it. Great timing, they released it about a month after I bought my dobinson adj rear.

You use it with your adjustable pan hard. It gets the angle back to stock.

 

[richardlillard1]

Replace the rear uppers.

 

[FJBen]

I bought this thing 3 years ago, and these things were on it when I got it. Owner had 0 clue about any of it, he had only had it about a year. Caster correction is the yellow OME bushings. I don't know which bilsteins or what the valving is. I can try to get some part numbers off them. I have never had it on a rack, other than the issue stated above this thing drives beautifully. Like 80mph with one finger on the wheel. Tires aren't wearing funny either.

So my vote is caster is bad being multiplied by other issues.
With 4” springs I’m betting you are negative on caster with just the bushings. That might not show up as a big deal on regular roads and everyday, but snow/ice loose traction it will show up much more.

couple that with work suspension bushings and possibly the wrong valved shocks and you have the recipe for squirrely handling.

inwould get it in the shop to measure caster or try at home first with an angle or digital level to see what you are at.

when I had Slee 4” springs, I ran his caster arms to get my caster into spec. I doubt bushings alone would be enough.

EDIT: my old 4” slee lift had -2.8 caster before any caster correction. after the arms, I had 4.4 positive and looking at my old posts on it, the Dartyness during braking disappeared after caster was corrected.

 

[landcrshr]

If I am in the snow, or higher speed in loose terrain(gravel) and off the throttle, the rear end tries to come around on me.

IME, you just need to slow down in the gravel, esp before the turns.

 

[BILT4ME]

IME, you just need to slow down in the gravel, esp before the turns.

No, no, no.

Before you enter the corner, you back out of the throttle, throw the rear out to put it into a slide, then steer right to go left, then drive it through the corner with the throttle.


Oh....sorry, I was thinking of AFTER the turbo......

 

[LandLocked93]

Oh....sorry, I was thinking of AFTER the turbo......

Hell yeah you were. lol

I can do what you propose on ice...that's about it.

 

[andyquoll]

How fast are you going when this happens? Is your front sway bar connected? Is the rear sway stiffer than stock?

I'm on 315 st maxx, 3.5" lift, delta panhard bracket. So, not too different from your setup. I do find that when mine breaks loose, whether coasting or on the throttle, it's the rear end that swings out. I quite prefer that to understeer but you definitely have to be ready for it.

That said, I have to be going pretty fast for conditions to get this to happen. The ST Maxx are the grippiest tire I've had short of dedicated snow tires, and I'm in the Colorado mountains so I see a ton of icy/snowy steep grades. Overall my 80 is one of the better vehicles I've had for snowy highway driving. I am totally comfortable letting the lady drive the 80 in bad weather and she has never reported any weird handling, although she does know how to handle oversteer.

 

[skidooman]

How fast are you going when this happens? Is your front sway bar connected? Is the rear sway stiffer than stock?

I'm on 315 st maxx, 3.5" lift, delta panhard bracket. So, not too different from your setup. I do find that when mine breaks loose, whether coasting or on the throttle, it's the rear end that swings out. I quite prefer that to understeer but you definitely have to be ready for it.

That said, I have to be going pretty fast for conditions to get this to happen. The ST Maxx are the grippiest tire I've had short of dedicated snow tires, and I'm in the Colorado mountains so I see a ton of icy/snowy steep grades. Overall my 80 is one of the better vehicles I've had for snowy highway driving. I am totally comfortable letting the lady drive the 80 in bad weather and she has never reported any weird handling, although she does know how to handle oversteer.

In the snow anything over about 20 and the rear would try to come around. No front sway and stock rear. If I'm on the throttle I get I understeer. This last weekend when I really noticed it in the gravel I was going about 35 when it tried to come around, as soon as i got back on the throttle, it started to push. I would also rather deal with over than understeer, but what I've got going on is excessive.

 

[skidooman]

Does this have a part time 2WD kit in it and locking front hubs?

Otherwise, the only other thing would be the bushings in the rear control arms.

No, stock drive train.

 

[1911garand]

Does this occur when your CDL is locked or unlocked? (do you have CDL button / 7-pn mod done?)

On my 1997 while driving on snow / ice, there is a drastic change in handling (while slowing down at speed) between CDL locked and unlocked.

 

[skidooman]

Does this occur when your CDL is locked or unlocked? (do you have CDL button / 7-pn mod done?)

On my 1997 while driving on snow / ice, there is a drastic change in handling (while slowing down at speed) between CDL locked and unlocked.

I do not have a CDL button yet. I have been looking for one without spending a fortune. I could use my hazard button for testing purposes I suppose.