Chevrolet Repair: 4x4 Question, chevy s10 pickup, differential action

Question
I have a 93 chevy s10 pickup it has the tbi vortec. Well my question is this i went to slip the truck into 4hi well it seems to go into it acts ok until i try to move foward it kind of jerks and doesnt seem like i would be able to drive down the road. well it almost acts like its in 4 lo but i switch it into 4 low theres a diffrence i can tell it went into 4 lo. Well i am just assuming maybe i got used to my 4 wheel drive with my 94 blazer in how it acted or maybe the 4 wheel drive in the blazer i had never realy worked. i mean i thought u where supposed to be able to dirve in 4 hi i just didnt know if it was still meant for a certain range on mph.

Answer
Hi Dennis,
The good news is, it sounds like everything is engaging ok.

Your 4X4 is intended to be used in poor traction conditions, but not on dry road.
That is because there is going to be a small amount of wheel slipping, and on good dry pavement, that will be hard on parts and tires.
There is no differential action in your transfer case, like there is in a full time 4X4.
While turning corners etc., it will cause the wheels to all rotate at different speeds...very slightly different maybe, but different none the less.
In the mud and snow, it isn't noticable. But on pavement, it is.

Now, if your rear tires and front tires are noticably worn different, or happen to be different sizes, that difference in rotation speed will be more pronounced, and the slipping/binding will be worse.
That is assuming everything is normal.

You could also possibly have a problem with the front differential, but I doubt it will be with the CV joints or drive axles, since they turn all the time anyway, and you would have noticed the jerking before.

Here is a thought....If you bought the truck used, and never used the 4X4 till now....is there ANY chance a previous owner might have had the gear ratio changed on the rear end, but not the front?
Almost unheard of, but possible if he didn't use 4X4, and wanted to improve gas mileage.
That would pretty much lock it up when engaged.

There is also a possibility of a drive chain or gear problem inside the transfer case, or a bad "U"joint on the front driveshaft.

Van