I put a Detroit Locker in my 88 F250 4wd 460 and it seems to work pretty well, with the drawbacks being that it tends to want to go straight in curves on the highway when I am on the gas, and the wheelhop is bothersome. Sometimes with light spinning it is really smooth, but sometimes it gets quite violent and I am afraid that it will hamper my snow bustin' abilities this winter. Sort of the opposite effect of what I wanted. Any suggestions? Also, this is my first visit to this site, it seems better than the others I have seen. I will visit the offroad forum. Is it redundant to post in both forums? Thanks for answering.

 

The problems you stated are what is generally going to happen when you go to a locking differential on a truck that sees lots of pavement. That is exactly why I am adding a limited slip instead. You are not experiencing anything out of the ordinary, in my experiences anyway. As for the wheel hop, it is caused by the added traction the locker gives and may be curable by getting rear add-a-leafs which cost about $60 or getting rear F350 springs. Add-a-leafs increase spring rate and lift the truck 1-2 inches. I believe there are blocks in the back, so removing these will both lower the rear of the truck to normal, and will also help reduce spring wrap (which causes wheel hop). The blocks create greater tortional forces on the springs, making them twist into an S shape. I did this on my F150, and wheelhop is pretty much gone. The ride may be a little more harsh, but the ride in a truck is not too good to begin with. Hope this helps and be careful in the winter driving on roads that are half ice, half dry. The locker may cause your truck to suddenly and violently turn sharply. My father hit a pole years ago in a muscle car as a result of that.

 

Yea, most of the effects are common to what I saw in my 88 Mustang street/strip car. I spent the first half a season shutting down before 4th gear as the locker would hit one tire harder than the other and cause the car to squirt one direction first. I put in a spool and took care of it. So the tendancy to push in the corners doesn't surprise me. I figured that with an auto it would be fine, as in my 460 Capri. My question though ... why would a limited slip be any different? On slippery pavement I would think it wouldn't see the breakaway torque needed to overcome the clutch pack. Pretty much wheel hop is cured as you say by preventing axle twist - your suggestions are appreciated. I'd hate to do those things without a recommendation ($$!!) and not get the results. Does your F150 have a locker now, or is it open? Any ideas what year of F350 springs will fit, or is new the better way to go? My truck has had a pretty easy life, so the springs are hardly worn and I'd hate to put in a thrashed set of old F350's and not gain anything. Thanks again for your input.

Dennis

 

Dennis,
Unforunately, I am not speaking on experience on a Ford truck, mine is open. I initially had the same question about the limited slip, but I have driven a chevy van and truck with LS (my friend is a diehard chevy fan) and there were no problems in snow/icy roads, or on the wet roads. I also have another friend with a chevy pickup (1/2 ton) and a LS and the same thing. I guess that it is because the LS will let one wheel spin slower, as the locker will only let one wheel spin faster. I put 3/4 ton springs on my truck, but I had to buy them custom, F250 springs were longer. I think the F250/F350 from 80-96 are the same since they both should have the Ford 10.25 rear, but I would definately check that.

 

I forgot one thing. The spring change in my truck, the 2000 lbs rated springs and the block removed, did cure my problems with wheel hop. It may have been just removing the block, the springs lifted the truck about 3 inches, but I think the increased spring rate also helped. In case you were wondering, I bought my custom springs for $125 each, if I remember correctly. Obviously, I had to go custom because of the diff. axles.
Rob

 

It sounds reasonable that taking the block out would cure the problem, or at least could. I don't want to change the ride height though, so the 350 srings ought to take care of that. I'll check it out. It does have the Sterling 10.25 rear.

Thanks again,
Dennis

 

 

A few years ago I put new springs on my truck.( f-150) The spring shop told me that all rear springs on 150's to 350's were the same length and only differences were thee number of leafs and the thickness thereof. ( I put on f-250 springs on mine and that cured all axle wrap even when using lift blocks. )

 

Dennis,
When I lifted my truck (extra rear block), put 33" tires on, and went from 3.07 to 4.56 gears(open diff), I ended up with some major wheel hop. I did two things to help prevent it. First I made up a set of traction shocks that mount above the spring pack, they pretty much took care of the problem. Since I wanted a bit more lift, I also installed an add-a-leaf, and it took care of any remaining axlewrap.
The F150HD (five leaf) and the F250 springs are identical. The 250 gets its added height from a block. The F350 springs will not fit, I believe they are 2-1/2 inches wide, whereas the 150/250 springs are 3"(but thinner). Anyway, I was told by a very reliable source that they won't fit. I recently replaced the rear springs on an 89 F150 with ones from an F250...they are identical.
It seems your best bet would be to install the add-a-leafs and remove the factory block. Be sure not to remove the block that also serves as the bump-stop. Another option is traction bars such as the ones offered by Rancho or ProComp. They are a sure-fire way to cure the axlewrap problem, but will probably set you back more than $200 unless you can make your own. Also make sure your shocks are good, good heavy-duty shocks will also help.
Let us know how it turns out.

Later,
Jon
92 Flareside 4x4 351 E4OD.

 

Thanks for the good answers. I have installed a set of Rancho kicker shocks that mount on top of the axel utilizing the outside U-bolt to mount one bracket, and drilling two holes in the frame to mount the other. This kit got rid of about 75% of the wheel hop. I did not want to go with the solid bar style of "traction bars" because I didn't understand how they would be able to accommodate heavy loads in the truck. In theory they would need to change length as the truck body moves up and down relative to the axel or else they would be in a bind and possibly change the pinion angle. Anyway, I will try the extra spring. I know what the lift block is that you are talking about, but I don remember the bump stop. I'm checking for a bad head gasket right now, so when I go back out I'll look. Is there a good place to get the extra leaf for the spring? Thanks again for the help.

 

I agree that there is a pretty major geometry problem with the solid traction bars. As the suspension travels, they actually do cause the axle and springs to twist, changing the pinion angle. I would imagine that the minimal travel that is seen on a street driven truck would not cause any problems, except when the truck is loaded down as you stated. It's funny how they call them off-road traction bars when in fact they severly limit articulation. I've seen some bars that mount above the axle much like the kicker shocks, and I'd think they would allow more natural movement of the springs.
As for where to purchase the add-a-leafs, I got mine from JC-Whitney. Not my favorite parts supplier, but they were decent (Rough Country) and far cheaper than any other place I found ($55 I think). They lifted my truck about 2-1/2", but mine is a shorty flareside (fiberglass sides).
On the 1/2 ton trucks there is only one block and it has a long arm sticking out toward the center that comes in contact with the rubber bumper on the frame. I assumed the f250 has this plus another block. Not sure on that.

 

Yea, I looked and the block is also the bump stop. I will just have to look around for the extra leaf deal. I know it was an option on the 250 from the factory, I might look in the shop manual and see what it shows there. Interestingly enough, I washed my truck today, then pulled out onto the road in front of the car wash, stepped down on it and got the biggest shot of wheel hop since I put the kicker shocks on.

Thanks for the help,
Dennis