Hi guys

I have just bought a 1995 f150 with 4wd, a 351w and I believe the e4od trans.

When I put her in 4wd I get the wheels skipping and bouncing. This might be characteristic of a vehicle with locked diffs, but I thought they would all be open diffs, even with 4wd engaged? It also seems to be intermittent. There is a LSD on the rear axle if that makes any difference.

 

That's normal... I'll bet it is much worse when turning.... You should NOT be driving on a hard surface with 4WD engaged.

 

yup.
it is also possible that someone changed one of the differentials and did not match the gear ratios.

 

As TJC said, if you're getting the skipping when you drive in a straight line it's likely that a previous owner changed the gear ratio in one of the axles (or that your front and rear tires are different sizes). Assuming it's not the tires, you need to get the gear ratios the same, otherwise you can really only use the truck in 2wd.

if it only skips in corners, that's normal. And as White 97 XLT said, don't use 4wd on non-slippery surfaces.

And yes, shifting into 4wd doesn't lock the differentials. If they're open they stay open, if they are limited slip, they stay that. The skipping is because there is no differential between the front and rear driveshafts. when you go around corners the front end tracks wider than the read so the tires need to roll farther. With no differential in the transfer case you get the skipping. It's pretty hard on the driveline, so you don't want to let it do that much. That's why you should only use 4wd on slippery surfaces.

 

Thanks guys, I think that it's behaving according to what you describe. I was unaware that there would not be a diff in the transfer case. I have a LR defender at the moment with full time 4wd and it does not act like that except with the diffs locked.

The front tires are at about 75%, but the rear ones are essentially new, so that is likely the problem.