I've got a '79 f150 4x4, man. hubs, 4sp, pretty basic. It originally had a 300ci, but the previous owner had a 302 built and put in. New front-end parts, bushings, susp lift, everything looked good underneath except a thick crust of oil under the bed from the last engine, a lot of obvious fire damage to the cab and engine compartment and the plastic laminated door tag (indicating a 'remanufactured' vehicle). I bought it cheap, as a project truck and expected problems to pop up but everything looked sound. It had been sitting for 5 years in a back yard; the result of a divorce, and before driving it home I put a set of tires on, changed the oil, checked the diff oil levels, bushings, joint play and changed the antifreeze. It ran great, handled well with no noise anywhere.
Drove it 20 miles with no problems at all, and got it 2 blocks from home and the rear end went. No power to the rear wheels at all, drive shaft turns fine no bearing or other grinding noise so I suspect a broken gear.
Now comes the fun part: had it towed the last 3 blocks, and dropped in the yard. I'm swapping the entire rear axle since I got a good deal on a matching ratio axle, LS I'm told but don't believe, and need to get the truck to a more work-friendly environment, the same place the donor truck is sitting. Had to remove one of the long-tube headers and replace it with an old manifold to get the front drive shaft back in (the last owner valued the exhaust system over 4wd, apparently) and I used the front wheels only to move it around in the yard with no problems.
My question is, assuming all of the front end parts are new, as they look and as the person that sold the truck says they are, would it be safe to drive it with the front wheels only to a friend's garage, 6 miles away?
Said friend says he knew a guy that drove his truck like that for 4 years, and he never had any problems, and had a similar setup; he also said it should be OK if I didn't get on it too much. This guy is an experienced mechanic but I can't help but wonder if he was thinking that IF I screwed up the front end that he might be able to sell me the front end out of the donor truck as well.
I know it's possible, but it seems to me that the front half of the drive train was designed to assist, not to move the entire weight of the truck.
Any thoughts, chastisings, corrections, hints, ect, anybody?

 

you should be fine for 6 miles, I broke a rear yoke on a dodge I had and drove around in FWD for a week until I picked up a replacement

 

ive done it for a couple days and it worked fine, just dont go doin to many clutch dumps and she should hold up fine

 

As tempting as it is to dump the clutch while watching the front tires burn, I doubt I'll be doing any of that. I was actually planning on laying into the secondaries a little bit right before (literally, seconds before) the rear end went so I'm a little gun-shy about that kind of thing at the moment.

 

It should be fine, theres no reason it should hurt anything. I had to drive mine about 20 miles on the front wheels when my front yoke on the rear shaft broke and launched the drive shaft out. Handles a little different especially around corners.

 

Took it out and drove it up and down the road a couple times this evening, re-greased the u-joints, no clunking or anything no excessive play. Doesn't handle too bad, I did expect some serious pulling when I did a u-turn, but it really wasn't that bad. THe wheel didn't return to straight when I sped up, but that's nothing. I've got a '65 Fairlane in which I've tightened the steering worm gear so much it's wheels won't return to center on their own, just a little more cranking on the steering wheel is needed, I can handle that for a few miles.
One thing did bother me, though. One of the people that helped the last owner rebuild the power and drive train is an old buddy of mine. I called him yesterday trying to track down another steering gearbox that was supposed to have been given to me with the truck, and he mentioned the only time the truck had been used in 4wd was when they tested it... in a grocery store parking lot. But I guess if that damaged anything I would have noticed by now. Thanks for the help, once again, guys.

 

Yeah, your fine especially for that low milage. I've had my bronco running FWD only for a few months, several hundred miles on it at highway speeds, no problems.

And ya, on your first couple high speed corners, or even in traffic corners, do be careful, it is a odd feeling in these trucks even if your used to FWD cars.. not bad, just a bit different.

G.

 

I drove my '75 highboy daily for two weeks on the front end until I let the clutch out a little to fast. Having all of my power diverted to the front axle snapped a stub shaft in half. Bad time to have an open differential.

 

I dumped the clutch once in my '97 Dodge/Cummins (with a mildly "turned up" engine) when I tried to pull out into heavy traffic and my Gear Vendors overdrive let go with a bang. It was installed behind the transfer case, so it was for rear-wheel drive only. I could hear no grinding of parts, but I had no power to the rear driveshaft. I shifted into 4wd and drove that truck for about a week to and from work (65 mile commute each way on I-5!) until I could take it into a shop. It was the only vehicle I owned at the time, so I had no choice except to rent a car. Anyway, I had no problems using front-wheel drive only with a high-torque diesel. However, I did take it easy.
Andy

 

it'll be fine

 

Iwas pulling a 25FT trailer with 1,000 gallons of water on board, and 11 drill rods. (water well drilling family) I lost the pinion. So, I locked in the front end and came home 35 miles. Oh yeah, it was a 84 F-250 with 237,000 miles.

 

I'm assuming the F250 front ends are beefier than the f150's are. I've got a 2wd '86 F250, and the front suspension on that truck is unreal. King pins instead of ball joints, damn-near indestructible. I assume they added some girth to the 3/4 ton 4x4 front driveshafts, u-joints, ball joints, yolks, and wheel joints that would make it stand up to more stress, but I haven't had the opportunity to closely examine one. I'd love to find a 4wd front end out of a 250 and make my '86 F250 into a 4x4.
I take my 2wd F250 off-road, and put it through hell pretty regularly, have been for the last 5 years. So far, it's missing a front fender, bumper, shattered grill, missing rear bumper, buckled and smashed side door, and the passenger side post on the cab is crumpled so badly that I have to push the back of the cab to get the passenger door to close. ALl of this is from hitting slick patches of mud with the wrong tires... except for the rear bumper, that was someone else's fault. But as far as the drivetrain and suspension, it's stood up to anything I've thrown at it... just keeps on going... with 334,000 miles. I'm thinking that when I finally get this F150 back on the road, or off it, that I'm going to have to be a little more careful with it than I have been with the F250. I'm in NW Florida, and we have a lot of soft sugary sand, slick clay mud, and rutted packed clay roads that result in unintentional jumps if you don't pay close attention to shadows and different shades of the clay.

 

Well, it took longer than expected to get the rear axle replaced. Took about a year, in fact. Drove on the front end for 6 months, with no problems, except that there was so much play in the steering (tilt steering linkages were worn out, pitman arm loose) that above 35mph trying to gently veer from lane to lane was impossible. But the front end did fine. THe rear end didn't. The right rear axle had snapped right at the wheel bearing and that wheel was loose. In the 6 months or so I drove it, it did OK, but when backing up hte drivers' side rear wheel liked to twist around and bind up. Eventually the axle bearing went and the drivers' side wheel flew off while driving. I was only going 20mph when it happened, coming to a stop but still not a fun experience. Thanks for the info, everybody.