Okay guys, I'm here trying to help my neighbor. He has an early 90's F150 with a 302 and I believe it's an automatic, I forgot to check that. Anyway, he knows I do mechanical work so he asked me to look at his truck. The driver side rear wheel does not spin when in forward gear. The wheel stays put while the passenger side spins; however, in reverse, both wheels spin no problem and he can move the truck.

I'm fairly sure this is a differential issue, which I told him. I'm also not big on going into differentials. Regardless, I'd like to give him a bit of a better answer. He thought it was the parking brake not releasing, but I don't think that's the problem when the wheel spins fine in reverse. I have a feeling it has something to do with a limited slip differential.

Thanks for the help guys.

 

I'm not quite sure what you are saying here. Are you on a dry surface and the truck will move in reverse but not forward? If the passenger side spins and the truck won't move forward, do you have the rear end jacked up?

 

On second thought, if the rear wheels are on the ground on a dry surface and the passenger side spins, and the truck won't move forward you probably have a brake problem. Did he have the parking brake on and released it? Those parking brake cables will bind up and not release, but I don't know if they will to that extent.

 

The truck is on flat, dry ground and the parking brake is released. Put the truck in a forward gear and only the right rear tire moves. The truck stays put, the right tire spins (he's parked on grass).

With the truck in reverse, it looks to move just fine, didn't look like it struggled at all. Both tires were rolling. It's just that with the ease that the truck (and both rear wheels) move in reverse, I'm doubting the parking brake on just one drum is stuck, but I could be wrong. In case I am, what should I look for with the parking brake cable? I've never had one get stuck before, should I take the drum off?

 

I would try to take then drum off. If the parking brake is stuck it will be nearly impossible to get the drum off without somehow releasing the parking brake. If the drum comes right off you will know the brake is not stuck. Maybe try taking the drum off first thing, or try turning the wheel by hand after jacking it up to see what happens.

 

Drum brakes work better going forward than reversing - they're self actuating. So a stuck e cable (or other parts) on the left could cause that. Pull it off the grass on to pavement would be a start.