I just bought my first ford, a 86 Ford F150 with a never used 4x4 (one owner!) with ~120k on it. This truck has the EFI 302 and overdrive, and doesn't have 1pc front axle. Don't know much more about it than that.
I'm excited for my purchase. (maybe my 10th vehicle ever, and first 4x4) But I do have a question

The PROBLEM
First fixed the linkage, then man-locked hubs, then put into 4wd H in shifter. I started backing out of owner's driveway, It felt very sluggish, and once I started turning, the truck started jerking and tire-erking, I thought I had broke it! I switched all back to 2wd, and it kept jerking a few feet more before releasing.

Conclusion
I'm guessing this is normal from not having limited slip?
I'm also guessing that the continued tire-erking after I set back to 2wd was due to dry sticky parts somewhere.

The Question
Are my conclusions accurate?



Background
I know auto fundamentals from HS classes. I know very little about 4wd and would like to eventually get the 4wd working on this beast. Sadly, it doesn't have the 1pc front axle. This truck will NOT see alot of 4x4 time or money for such. I'll save that for a dedicated rig.

 

Four wheel drive vehicles usually don't allow for driving on dry pavement without jumping because all 4 wheels are locked together and don't allow for any slip which can take place in mud , snow or on ice. It sounds like the system is operating normally. If you don't need the 4WD , best to keep the hubs unlocked.

 

thanks! well, at least I know it works

 

That erking sound is the 4wd system working properly. You probably have locking differentials that engage when you put it in 4wd. I bet your front axle is a TTB (twin traction beam) setup, most likely with a dana 44.

Normal 4 wheel drive systems, when engaged into 4H (four high) or 4L (four low) send power through the transfer case [which is behind the transmission] to both the front and rear axles. Unless you have locking differentials (aka Lockers), you will have one tire spinning on both axles - that's open differentials. There are many different types of lockers, most popular in Fords [that I know of] is called Posi-Trac. That will send power from the motor to the tire that is spinning, so it can get traction on that tire. Sometimes it works; sometimes you just dig a hole.
By the sound of it, with the erking you're getting, you have true lockers that lock all four wheels together and make them [all four] spin at the same rate. Therefore you're dragging one tire when you go around corners on dry pavement. I'd avoid doing that too much.
As to the continued tire erking after setting it back into 2wd: Yes, the parts stick a little. It's not an "old truck" problem or anything. The parts just need to get the load off them before they can disengage. The quickest way I've figured out to do that is [if driving forward in 4wd] to set your system on 2wd and drive backwards for about 10-20 feet. That should take the load off the system so that it can disengage.

Hope that wasn't too confusing and helped you understand your 4wd a little better.

 

thanks for the priceless tips, Old4xford