Today was the first snow so I locked the hubs and engaged 4 by 4 but the truck drove really rough. Is this normal? BTW it's a 90 F150

 

Rough how?

 

felt like it was holding back and jumpy ( smooth ride then lurch and jerk around). The engine is fine and I was shifting the right way as I always do. Beats me

 

has any work been done to your diffs? sounds like an indifferent ratio. tires sizes front and back the same?

my truck did exactly what your describing when i had a 3.55 front and a 3.08 rear. might wanna look into that.

 

Tires are the same size I think. I think stock diffs but my trucks been owned by a string of 17 year olds so I have no history on it. How do you tell your gear ratio?

 

You could check the tags on the axles, but that would only help if they were different, if the same it's still a possibility someone changed the ratio and put the original tag back on.

Best bet would be to jack one end up, spin the driveshaft while counting the tire revolutions, then repeat at the other end, and compare. They should be the same, or very close. Just over 3 tire revs would indicate 3.08, 3 1/2 would be 3.55, 4- 4.10, and so on.

 

Counting rotations will work but i think i would just pull the rear cover and count teeth. it will not hurt to change to fluid back there anyway. as for the front i would start tearing it apart because thats probably where your problem is. But being owned by a string of 17 year olds i would want to do all the maintance on the front end. I know how i treated my truck at 17 and it was not good. So tearing it all apart and changing fluids and u joints and such as needed will not hurt.

 

Another possibility would be the u-joints in the front axle or the inner bearing for the axle shaft inside the spindle being worn out. Those will cause the front end to act all wonky also. First thing to check tho is the gears and make sure you don't have a mismatch between the front and rear.

 

Is it more common when your turning? Is it heavy snow heavy, or just a little bit of light snow.

4x4 will tend to bind when turning, even if you are on snow, and especially if your on dry pavement.

 

i dont think u joints would cause a hop, a clunk and funky noises definately, never heard of them causing the whole truck to hop though.

best way is pull the cover on the rear and count teeth... ring gear teeth / pinion = ratio

the front thats a bit more of a pain in the ***, but at the same time you can see the axle shafts so unlock your hubs t-case in N and theres no need to jack it up just spin the front shaft and the axles will spin...it was previously mentioned how to do that, less accurate but it works.

the tag on my rear end said 3.55 pulled it counted the teeth and found they were 3.08... its very likely someone swapped (most likely the rear) diff. thinking better fuel economy or pulling power or whatever didnt think about the change in wheel speed causing binding between the front and rear. so the truck is either pulling itself appart of trying to make itself shorter.

or if you happened to be turning it would do that also even if the diffs are the same

 

It has a rebuilt front end and i just changed the fluid and all the teeth were fine

 

How much snow are you running in? You should never run 4x4 unless needed I will agree it helps track better but its still hard on the 4x4 components. If your back tires are spinning out and not getting traction you have some options.

1. put weight over rear axles helps to provide weight so the tires can grab onto the slippery snow better.

2. Get winter tires. Not always feesable with money and rims ect.

3. go easy on the accelerator the slower you start out the more time your tires can react to grip.

Now i Hope your not throwing the truck in 4x4 and trying to get road speed out of the truck. Thats how you mess your 4x4 up. You can only go about 20mph i believe with 4x4 engaged. Don't quote me on that but you cant go Normal 2 wheel drive speed.



Note: Im not trying to be rude because i don't know how your driving and just throwing tips out from what i've seen my friends and other people do. And just going by what i
'm told in the posts.

 

Pretty sure my visor says your good to 55 mph in four wheel drive. I know i have driven mine at highway speed in four wheel drive on bad roads without any issues. the only issue you should really have that is normal would be the jumping when at full turn in four wheel drive because of the angle on the u joints. You can count out any wheel bearing problems because it would act the same in two wheel drive if they were bad. My money is still on different gears.
One thing to consider my be bad hubs if the teeth are starting to get worn it could be jumping every so often, and in my opinion the stock hubs are junk.

 

Now i Hope your not throwing the truck in 4x4 and trying to get road speed out of the truck. Thats how you mess your 4x4 up. You can only go about 20mph i believe with 4x4 engaged. Don't quote me on that but you cant go Normal 2 wheel drive speed.

I go in and out of 4H at highway speeds as road the condition/lane condition changes. Running on dry pavement in 2h, hit a section of deeper snow covered road from blowing drifting I hit 4h, or when simply moving into a un plowed lane to pass slower traffic for example. Same passing on a two lane road in the slop, hit 4w before doing so, ovoid sudden wheel spin mid doing so!

Hubs locked running in 2h, let off throttle, pull lever back, back on throttle. Back to 2H same thing, off throttle, push lever forward, back on throttle.
You don't have to let off the throttle to go back to 2w however keep in mind it won't actually shift, will remain in 4w, until you do so.

 

Yep 2H to 4H setup for Highway speed... 4L is only good for slow speed!