what causes BAD wheel hop in reverse

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challenger57

cuda57
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york, pa.
I've had this issue of wheel hopping in reverse after doing a auto to 4spd conversion. I can not back up any incline because the rear hops up and down terribly. Now i did do a gear change in the 3rd member that I did myself for the first time. I had other people who have done gear changes look at my setup and they said it looked good. I have no problems going forward, no whine no grind, just can not backup. Checked all springs, mounts, shackles everything looks good. Everything is the same parts as it was when it was a auto. I had a nephew hang out the pass side door to look under the car and he said the front of the rear is tipping down about an inch when trying to backup. Sounds like alot to me. The tranny is an OD tranny. Could the leaf springs be too weak to handle the torque of a clutch setup as oppossed to an auto that has some slippage. Any help appriciated. Thanks Mark
 
well, i would think that if he can actually "see" the pinion titling down as you back up, then i would believe that as you start to back up, something in there is binding, and as you continue, it releases,or "jumps" back up, causeing that sudden "pop" back up
 
Well, you're in PA so point it up a hill and let it roll backwards down the hill. Maybe you can feel it acting up, and with engine off you may be able to hear it.
 
Check the perches and make sure one or both haven't popped loose or bent. Check your u-bolts and make sure they are tight. Also make sure the spring clamps are in place.
 
Drive shaft is new and cut to proper length, thought about e-brake hang up, no hang up even tried applying e-brake just to see if brake binding, no luck there. I will try the drift backwards method to listen for binding. Spring clamps are secure but I will double check u-bolt tightness and perches.
 
What type of OD trans did you put in? I'd be willing to bet it screwed up the driveshaft/u-joint angle.
 
This is actually pretty common, I've even seen it in bone stock trucks when trying to backup a load or a trailer. Part of the problem is the springs are made to work in the forward direction, not the reverse. Yes the pinion is going to point down in reverse, up in the forward position. The fix Chrysler had for some of these was to adjust the pinion angle with wedged shims under the spring perches but that's probably not all of your problem, You need new springs and then adjust the pinion angle for approx. 2 -4 degrees nose down with the weight on the vehicle.

Other than that I guess you could put traction bars on it backwards. :)
 
It might not be the rearend - you mention an auto to 4-spd conversion. Could be the clutch grabbing. I had a truck with a grabbing clutch that would buck pretty hard - but only in reverse & compound low. In the truck I could get it to back up smoothly by reving higher than needed and really feathering (slipping) the clutch in slowly.

That said - could be any of the things mentioned.
 
Did you take the clamps off the front of the spring ?

It's normal for the diff to want to wind down in reverse.

The problem should lay in the springs
 
Correct me if I am wrong, this car is a 65 cuda, shouldn't the pass side springs be diff from the driver side. When I look a pics of new springs it looks like the stack of springs are shifted more forward on the main leaf on the pass side. Could this have been done to prevent the kind of prob I am having. My current springs are the same on both sides. The previous owner had a 8 3/4 rear from a 71 duster put in it. They may have used the duster springs also-don't know!. If I ride with 2 passengers in the back seat I bottom out on the pinion snubber that is adjusted about 1 1/2 inch below the floor. My shocks are QA1 adjustables so all my bounce is in the springs. Now to me this would indicate weak springs. This week end I will be i Ohio and am going to make a stop at summit. I might consider getting a set of the XHD springs. I know I will have to make a spacer for the driver side to even out the ride height. Something I have noticed, knowone makes traction bars for mopars, just the slide a link. What gives. Keep giving suggestions Thanks
 
challenger57 said:
Correct me if I am wrong, this car is a 65 cuda, shouldn't the pass side springs be diff from the driver side. When I look a pics of new springs it looks like the stack of springs are shifted more forward on the main leaf on the pass side. Could this have been done to prevent the kind of prob I am having.
Click to expand...


It wouldn't matter if you have 19 leaves further forward, when in reverse the rear winds up the opposite way. . .

So it will fan the front spring section and not the rear. . .

ARE the clamps on the front section of spring?

Traction bars aren't going to help in reverse. . . . .

Mopars don't need traction bars or snubbers
 
What type of shocks do you have on the car. I've seen air shocks do this combined with weak springs to get the car lifted up a little. I had a car do this with a cracked bell housing. He was running a aluminum bell with out the inspection cover which also strengthens the bell.
 
I think what is causing it is you flooring it in reverse :)

Sorry couldn't resist.

Check the bands on you leaf springs particularly the ones in front of the wheels.

You are not running air shocks are you ?
 
NO AIR SHOCKS, as I mentioned QA1 12 way adjustables, also I never mentioned anything about FLOORING it in reverse, I actually have to slip the clutch even on flat ground. All bands are rapped around the leafs. The OD tranny is a mopar cast iron piece. The thought about traction bars was just a thought for better forward hookup.
 
I had a cracked ring gear once that caused that, but it was more of a once a revolution pop than wheel hop and it was only in reverse.

The rear-end did not last long after that.
 
I saw this on a car once and it turned out that a couple of the leafs on one side were broke. The cracked leafs were between good ones so the cracks were hard to see.
 
My son has a 2005 Dodge diesel 6 spd. He bought it new . I did alot of performance upgrades to it and the standard clutch could not handle the horse power and torque increase.. It would slip under a hard pull. I purchased a South Bend Con FE Ceramic clutch. $1500.00. wasn't cheap. It ddoes excactly what you are describing with your car. When backing up with our race trailer on a slight incline it would wheel hop unless you would rev the engine and ride the clutch.

After one season of towing with it i and racing it. he ripped the center out of the disc, I called South bend and explained this to them. They replaced the whole set up for free. There was a recall on the disc, The center was weak and couldn't take the clutch Chatter. It was more noticable in reverse because of the lower gear. I still have the same issue with the new clutch but it is built stronger and made to take that abuse. They explained the ceramic disc grabs hard and causes center of the disc to bounce against the springs .

I am only mentioning this because you said if you rev it and ride the clutch it doesn't do it.. Your problem may be in the disc weak springs from a cheaper clutch or low slip from a race clutch. South bend told me I couldn't have the best of both worlds. I still ride the clutch in reverse when backing up.

One thing though, when my son rides this clutch pulling out in third wiith the motor turned up racing it. Even though you smoke the clutch on the start it does not slip when it is engaged. Its in for almost three years now. It still does the reverse hop but we're used to it. If you let the clutch out fast with the motor reved up in a higher gear it kills the motor. The stock clutch would just go up in smoke.

Could be the disc, Just a thought? The Leaf springs are not weak on our 3500 dodge and it does what you are describing. The stock clutch did not do this, Like I said not saying this is deffinately your problem but again something to check into. Steve
 
What you are feeling is the rearend twisting down and the leafs bouncing it back up, over and over again. Anything that can cause the drivetrain to start bouncing. Its most likely the first two but here are some other causes

1.incorrect pinion angle-adjust pinion angle with shims to 4
2.weak factory springs- switch to xhd or super stock springs for better forward traction and less bounce
3.clutch that has a weak center section and/or springs to connect the hub to the disc (cheap parts store clutches) also a performance clutch that grabs very hard due to a increased pressure plate clamping force
4.Loose or worn trans mount-even some cheap rubber trans mounts move to much IMO I would switch to a poly mount
5.low gearing makes this problem more noticable
6.warped flywheel
7.flooring it [-X
 
Update on reverse wheel hop---Well I replaced the leaf springs with XHD springs from Mancini and I STILL have the same problem. I guess next step is to pull the tranny and check the clutch, after that I think it is grenade time!!!
 
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