96 Yukon 4X4 Binding Issues:

[Gregorylights]

Need some help with my 96 Yukon and the 4X4.

The truck just rolled over 200k Highway Miles and with Winter coming I'm worried about the 4X4.

The truck has Auto Shift Push Button 4X4 and when I push it into 4HI it take a few pushes to lock into place but once it is engaged and the truck is placed into Drive it will Bind the front end up and wheel hop while driving forward it has a lot of torque but just wants to Bind everything up.

Once I go to shift into 2WD the truck does not wanna come out of 4HI and the Indicator Light will say 2WD and the Front axle will still stay Engaged.. After pushing the button a few times and shifting into reverse it will finally come out of 4x4 and be fine..

I am needing to know what to look for and what parts could cause this so we can get it into the shop and fix it before winter..

Also Note: Truck has 3in Torsion Key Lift With 3In Rear axle Blocks:

Thanks

 

[SunlitComet]

you will get some real minor binding on dry payment but not a enough to bind everything up real bad to hop a lot. ensure your front and rear tire diameters and axles ratios match up. also you should be able to go to 2wd to 4hi at any speed you only need to be in nuetral and creeping at 1-3mph for in and out of 4lo. if tires and axle gears match i would look into diagnosing the tcase as the issue primarily. you could check for any tcase codes to help a bit. 1996 have limited electronic diagnosis for the tcase system tho. it is mainly for controller and shift motor diagnosis really.

 

[Gregorylights]

If I were to shift it into 4HI while going down the road at 20mph it would be like pushing in the parking break at 20mph.. Could this be caused by maybe bad Binding CV shafts or Bad U Joints in the front axle??

 

[clownracer]

if it worked fine the last time you used it and you haven't changed tires or anything else drain your front diff and make sure that there is fluid in it and that its not full of metal chunks

 

[SunlitComet]

i think you better get the wheels off the ground and check some stuff.make sure vehicle is in 2wd and tranny in park. you should be able turn each front wheel individually and smoothly with no noise and no rotational movement of the front driveshaft when doing so. conversly the front driveshaft should turn freely by hand with no noise and no rotational movement of the wheel or axle shaft assemblies. the rear drive shaft should be locked in place and turning either rear wheel should turn freely and turn the other in the opposite direction. start with that. if you have any issues at all note what happened come back here with the details.

 

[Gregorylights]

The wheels turned fine the truck has all new front end parts with new Pitman arm, Idler arm, ball Joints, tie rods and the Wheels bearings seem fine... Idk about CV shaft the boots are fine and have no tears.. But the U joints in the front shaft seem original and I'm gonna swap diff fluid tonight..

 

[SunlitComet]

if all parts mentioned turn as suggested the you must have a mismatched gear tire size or something wrong in the tcase or front gearbox tho you do not seem to indicate a gearbox issue. yet.

 

[Gregorylights]

Ok so changed front diff fluid dident find any Shavings or anything and seemed to be fine but the fluid looked to have some miles.. So switched it with Royal Purple 75-90wt
After doing that I tried the 4x4 and was gonna see what we got.. I push it into 4HI and it flashed for about 30 sec and shifted into 4HI.. After that I put the truck in drive and proceeded to pull forward and it seemed like new for about 200feet and started to seem like a grinding noise like the Drive shaft might be binding up with a bad U joint or there is a gear issue.. As I'm aware there has never been a gear change in this truck but might just have to take it to the tranny shop and have them check it out.. The new Fluid seemed to help a little bit.. So Friday I'm gonna try changing the U Joint in the Front Shaft.. See if it makes it better if not I guess it's gonna be to the shop to check out gears..

 

[RedCrush]

I would suggest not engaging 4 hi or 4 low while rolling. come to a complete stop, put the trans in nuetral, select 4 h or low and wait till the button stops flashing and stays solid then put it in drive. let me know how that works out.

 

[SunlitComet]

on the contrary 4hi to 2hi can be done at any speed. and for 4lo the while the transmission needs to be in nuetral it it recommended that you coast 2-3 mph to ensure an easy and fast tcase shift.

---------- Post added at 04:02 AM ---------- Previous post was at 03:51 AM ----------

Ok so changed front diff fluid dident find any Shavings or anything and seemed to be fine but the fluid looked to have some miles.. So switched it with Royal Purple 75-90wt
After doing that I tried the 4x4 and was gonna see what we got.. I push it into 4HI and it flashed for about 30 sec and shifted into 4HI.. After that I put the truck in drive and proceeded to pull forward and it seemed like new for about 200feet and started to seem like a grinding noise like the Drive shaft might be binding up with a bad U joint or there is a gear issue.. As I'm aware there has never been a gear change in this truck but might just have to take it to the tranny shop and have them check it out.. The new Fluid seemed to help a little bit.. So Friday I'm gonna try changing the U Joint in the Front Shaft.. See if it makes it better if not I guess it's gonna be to the shop to check out gears..

before you put in more parts that are not know for sure to be needed yet, i got another question for you. when you go into 4hi and this problem starts, do you go out of it right away and it stops entirely. if so, without moving, can you engage again and travel so many feet and be fine till say another 200 feet? this is important.