4WD sluggish or binding
 

I have a 2000 4-door 4WD Blazer with 2-Hi, 4-Hi, 4-Lo and Auto 4WD at the switch.

This week I decided to check the 4WD system in preparation for winter but when switching to 4-Hi it felt like the transfer case engaged but was 'tight.'

It seemed to bog the engine a bit (while rolling, in gear) and would coast to a stop much faster than when in 2WD. The lights on the switches seemed to work as expected and would switch back to 2WD on request. I can get it to engage axles on demand but it just doesn't feel right. Other than feeling like I'm towing something heavy, it seemed fine.

I put it in 4-Hi and drove through a parking lot with my head out the window and it almost sounded like one wheel was skidding and not turning, but it was raining so there were many new noises coming from under the truck due to the water.

I've done a quick once-over checking fluid and hoses but there are no outward indications of problems. The fluid is light blue and clean.

Could this be something as simple as low fluid? I do have new tires on the back and worn ones on the front at the moment but they're the same size.

How much difference is there front to rear? This very well could be the source of your problem.

I *thought* they were, but you just made me look. I think I just learned something.

There are 235/70-15 on the front an 235/75-15 on the back. That might just be enough to make things chunky.

Well, I was gonna get them changed this week anyway. Maybe I'll make it tomorrow.

And yes, they're all at appropriate pressures. I need to get whatever mileage advantage I can get.

That is a LARGE difference in the outside diameter of the tires. Even a really worn out tire vs a new one of the same size is enough to cause some drivetrain binding.

DO NOT drive it in 4wd again until you get the sizes matched up.

Yeah, that all hit me at once. I guess I was too worried about other things to look at the obvious. I messed with it in 4WD for less than 50 feet so it should be fine.

I have another Blazer that has been ornery lately, wanting an intake gasket, a don't-remember-what sensor, thermostat, battery and coolant temp sensor. When the other one got funky with the 4WD I guess I just panicked.

Thanks for the info and pointer to the obvious. I'll be getting new tires in the next couple of days.

I am also having a similiar problem when I enagage the 4x4. i noticed mine to be very sluggish and while turning the inside rear wheel would skid?? All my tires are the exact same, any idea's? 1998 Jimmy 4dr 4x4 184k

Turning when in 4wd will always produce binding when you are on high traction surfaces. There is no center differential in a conventional 4wd vehicle.

If you are experiencing binding while driving straight with the 4wd engaged, then you ned to check what has already been listed. Look at tire pressure. If that checks out fine, then you may have a problem internal to the transfer case. You could diagnose that by removing the front driveshaft and engaging 4wd. Only drive with the front driveshaft out for a VERY limited time just to diagnose the problem. If the issue is still there, then the transfer case is at fault. If not, then you could have a bearing problem in the front diff.

At the other extreme, the gears may be different front to back.