rear axle shifts

[95TwinTT]

i heard if you take the front drive shaft off (4wd) you will get better ges milage.

it kinda make sense one less thing for the trans to turn the tranfer case when not in use.

i will do it next year and see what happens

With these trucks, the front shaft does not move unless the four wheel drive is engaged. It is disconected at the transfer case on one side and the axle on the other end. There is no power drain from having it in the truck. The only way it would save fuel is from the weight savings which would be not be that much considering the truck weighs 5600 to 6000 pounds.

On older models it would be true where the shaft is spinning all the time the truck is moving.

 

[96ProCompTahoe]

wait, the front end spins all the time in these trucks since it doesn't have manual or auto hubs on it like other suv's and trucks have. granted i can't say i've ever been under my truck when im driving it, but i thought it spun all the time. haha

i have heard the drop the front drive shaft and it gives you a mile or so on your miles per gallon from a couple people. and i've seen the kit to put manual hubs on them to save the gallon or two. (kits freakin expensive BTW)

 

[95TwinTT]

wait, the front end spins all the time in these trucks since it doesn't have manual or auto hubs on it like other suv's and trucks have. granted i can't say i've ever been under my truck when im driving it, but i thought it spun all the time. haha

i have heard the drop the front drive shaft and it gives you a mile or so on your miles per gallon from a couple people. and i've seen the kit to put manual hubs on them to save the gallon or two. (kits freakin expensive BTW)

There is a device hanging on your front axle, on the passenger side of the diff. It ingages and disingages the front wheels when put into four wheel drive. At the same time, the transfer case is shifted with the manual lever.

Earlier models use vacuum to shift the front axle, while later models use electric actuators. There are electric replacements for the vacuum models when they go bad.

So back to the drive shaft, it does not turn unless you have the 4 wheel drive engaged. :thumbsup:

 

[qlc1964]

what i did to confirm this is i straped myself under the truck and had my wife drive down the street at 35 mph and it was spinning .(SIKE):lol:

but i did spray painted a spot on the u joint and went for a drive and it wasn't

in the same spot.
OR i can put a glob of grease on the drive shaft and drive it to see how
the gease comes off. if the grease is on the under side of the truck
you could say it is turning ? the 95 have a lever on the transfer case like the

gear shift to the trans

 

[95TwinTT]

what i did to confirm this is i straped myself under the truck and had my wife drive down the street at 35 mph and it was spinning .(SIKE):lol:

but i did spray painted a spot on the u joint and went for a drive and it wasn't

in the same spot.
OR i can put a glob of grease on the drive shaft and drive it to see how
the gease comes off. if the grease is on the under side of the truck
you could say it is turning ? the 95 have a lever on the transfer case like the

gear shift to the trans

If your front shaft is turning while you are not in 4 wheel drive, you have a problem. The axle shift device is not working. I had to replace mine once at about 35,000 miles. It is not difficult to change. The vacuum operated ones are not very dependable. I suspect vacuum leaks as the truck ages are the problem. The electric ones are the best.

It has been a couple of years since I did it and I had also done one on a S-10 blazer. One of them I converted from vacuum to electric, but I can't remember which one.

I recommend checking these things out on a hoist rather than riding down the road haning under the truck. :yesnod:

 

[mygreen98]

this problem is not the bearing in the transfer case. i change mine and same problem as mentioned in the thread. bump/thump in rear when stop and take off. while changing t-case bearing i checked all ujoints(removed cups and checked needle bearings and grease), greased spline for rear shaft. same problem. i checked the rearend, found lots of play in the pinion shaft. this seems to be the problem. hope this info helps

 

[happyyank]

Problem Fixed

I'm going to guess you are feeling the drive shaft sticking and then releasing on the spline, where it goes into the rear of the transfer case.

When you come to a stop, the banjo housing wraps up slightly moving the drive shaft. It is held in place with the brakes. As soon as you release the brakes, the spline can slide back to the cruise position.

If it is sticking, it will make a soft clunking noise and you of course can feel it too. It may not do it each time you stop. Easy fix, just pull the drive shaft off and put a little grease on the spline.

Thank you for the great info ...I pulled the drive shaft today and greased the spline. All is well... The clunk is finally gone...:yesnod::yesnod::yesnod:

 

[bacon612]

this problem is not the bearing in the transfer case. i change mine and same problem as mentioned in the thread. bump/thump in rear when stop and take off. while changing t-case bearing i checked all ujoints(removed cups and checked needle bearings and grease), greased spline for rear shaft. same problem. i checked the rearend, found lots of play in the pinion shaft. this seems to be the problem. hope this info helps

I am having this problem as well. I just replaced my u joints and greased the spline. About a week or 200 miles later the bump bump and noise is back when stopping and starting from a stop. So I have 2 questions:

1) Would it be possible that i just need to re-grease the spline? If so, why does it need more grease so soon?

2) How were you able to tell if there was play in the pinion shaft? I am hoping there is nothing wrong with my rear end.

Thanks for any imput. This forum is awesome!

 

[happyyank]

I am having this problem as well. I just replaced my u joints and greased the spline. About a week or 200 miles later the bump bump and noise is back when stopping and starting from a stop. So I have 2 questions:

1) Would it be possible that i just need to re-grease the spline? If so, why does it need more grease so soon?

2) How were you able to tell if there was play in the pinion shaft? I am hoping there is nothing wrong with my rear end.

Thanks for any imput. This forum is awesome!

I' ve put about 700 miles on mine and haven't had to regrease it yet. i did put a very heavy coat of grease on it though....As far as the second question i have no idea but would also like to know the answer...

 

[mygreen98]

with truck off ground and in neutral, move rear driveshaft back and forth. you can then feel the play in the rear. if you can move it back a nd forth alot without feeling any resistance in the shaft, you have excessive play in the rear.

 

[wabwab]

I want to do this to save my sanity... but does anyone have any pictures or diagrams?

I suppose I could use a Hayes book to look up how to replace U-joints... just to get me going in the right direction...

 

[718frankb]

check out youtube theres some vids on there that are helpfull