When I kick out of four high I have to shift into neutral to get the rear end to unlock. Is this because it’s a dually or is there so<?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" /><st1:PersonName>me</st1:PersonName> think that needs to sent to the dealer. With my 96 4x4 all I did was hit the 2 wheel button and go.

Huh? The rearend is engaged all the time. Did you mean the front differential?

I am thinking he means that it is engaging the locker somehow. This isn't normal as the rear end shouldn't lock up unless you start to slip and should automatically unlock itself. Engaging the 4wd shouldn't have any effect on its operation. If you meant what coyotekid thought, then it does take just a second to disengage the front end after you have been in 4wd, but it shouldn't be very long, maybe a full rotation of a tire. Anyway, if the rearend is acting strange i would have it looked at.

If the rear was locked all the ti<?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" /><st1:PersonName>me</st1:PersonName>s it would bind up or start jumping on every tight turn you made on black top. One wheel has to travel more then the other and that were you get the binding or jumping out of the other wheel. I saw that on so<st1:PersonName>me</st1:PersonName> other guy new GMC at a stop and grab the other day.

I was thinking it was the front at first. But it feels and looks like the rear to <st1:PersonName>me</st1:PersonName>. Driven from lose sand to hard packed dirt, making a turn the rear acts like it is binding up and I have to shift out of drive to disengage the binding. I am going to call the dealer about it today.

Thanks

Sorry, I think I understand what you mean now. It feels like the rearend is locking when in fact it should be "unlocked." I guess I just didn't understand you correctly.

Have you used any exotic lubes or additives in your rear diff. that could cause the G80 clutches to bind, etc.?

No, I only have about 4639 miles on it. So I am riding the warranty out right now. I'll be taking it to the dealer next week.
Thanks

If it is in four wheel drive it is normal to feel binding when you turn.... There is no differential between the front diff and the rear diff. So unless you are on a slippery surface the system will bind. It will even bind on grass. Every 4x4 I ever drove did this except for an all wheel drive van I owned. It had a differential between the front and rear axle, no binding. At least this is the way it has always worked for me.