Hi guys,

I've got an 89 F250 7.3 IDI 4X4 single rear wheel that is the worst off road vehicle I've ever had.

I hunt, fish, and farm a bit and I can't count on two hands how many times I've had this truck stuck. If it's wet at ALL it'll get stuck, even on level ground in wet grass.

I've been researching, and pulled my axle code (C5) and was shocked to learn I have a limited slip diff instead of an open. I'm guessing my preload is so low on this truck rated for towing that the LS just doesn't work?

Or could the diff need rebuilding, and clutch plates need replacing?

Or do I need to drop in an Auburn or Detroit or other posi or LS or a locker?

Understand that the truck is probably worth $1500, I'd rather not spend 1K on a detroit locker, but I'd love to upgrade the off road traction a bit.

Advice?

 

I'd replace the clutch plates, Change fluid and make sure to add the ford lsd additive. I've got an 89 idi with the C5 code axle. Plan on eventually doing the clutch plates. Good tires help alot too.

 

If you have a 4x4 and you are getting stuck, I'd look at whether or not the front axle is doing anything....

One of the problems these trucks have is all the weight is up front. If you have an empty bed, there is very little weight on the rear tires and thus very little traction. I used to notice the same thing with my '88, but as soon as I popped it into 4x4, I had no trouble.

Given that, yes the clutches are worn out on your limited slip. That's normal for a truck of that age.

 

Interesting, we have a couple open diff ranch trucks that do great in the mud. Mine with the posi is even better. Odds are its shot, they dont work all that great after 20-30k miles, especially if its done alot of towing on windy roads. Good news is theyre cheap. Also, goes without saying that tires make as much or more difference than 4wd itself. I go places now in 2wd with my new cooper ST maxx's that i couldnt before with my mostly bald M55s in 4wd.

 

It's an expensive option, but from the research I've done the Detroit Truetrac limited slip is probably my best bet.

The truetrac plus a master diff rebuild kit will run 1k in parts without labor, but it'll give me a gear driven limited slip without clutch plates to replace, and the rebuild kit means that axle is good for another 20 years...

I intend to keep this truck, so it's probably worth investing in. 185k miles now, motor is good for a long time.

 

I would say drop a lunchbox locker in there but for a TracLok you'll need to replace the carrier. May as well go with a proper locker, either Detroit or Yukon. Run the TrueTrac up front, it's not a true locker and may need brake application to distribute power to both wheels.

 

Thats only in zero traction conditions. Same as any other limited slip, the more torque you can put to the ground, the harder it will lock. The truetrac is smoother and more aggressive than a clutch type by far, and lasts the life of the axle. But in zero traction, such as ice, there is not enough traction to cause the friction in the posi to lock it. For a DD, i think its the best of all worlds, traction when you need it, doesnt care about towing or being loaded heavy, behaves like an open diff when driving in winter conditions (not to be confused with stuck). If you do get in a situation where it wont lock and you need it to, you just ride the brake a sec and it will lock, it "tricks" it into thinking it has traction. A clutch type, and especially a locker, are suicide on slick roads.

I dont have them yet, but im really looking forward to puting truetracs both in my 92, and my 69 Fairlane

 

first thing i would suggest is different tires.
my 88 would also get stuck on wet grass in 4 wheel drive. then i put aggressive off road tires on it and it has not gotten stuck since.

 

Unloaded in 2 wheel drive my truck is hopeless, it's either spinning or hopping so bad you have to stop. You have to keep in mind you are essentially pushing a lot of weight in the front with a drive axle that has very little weight over top of it. To make matters worse the leaf springs are incredibly prone to axle wrap. In 4 wheel drive the truck will go about any where it will physically fit, although the narrow tires don't behave well in soft sand or deep mud.

I would first make sure that your 4 wheel drive is functioning properly. Other than it being a pain to have to lock the hubs you shouldn't be getting stuck that often if it is.

 

I've never driven a TracLok that was anything but smooth. I guess if you install an extra disc or shim it really tight it might be less inclined to disengage. I've never bothered, for my stuff if it's a heavy vehicle or gets abuse it gets a real locker.

I've never had a problem driving TracLoks on ice, it's more or less like driving an open diff (unless maybe you shimmed it real tight?). Lunchboxes and detroits require a bit of common sense, but again I've never had any issues driving them on ice. Your experiences may vary if it has been in light short wheelbase vehicles... But in heavy long wheelbase trucks and full size cars I've never found anything suicidal or even eyebrow raising.

 

Lincoln, and miller make great lockers if your not going to drive on the street much.