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Discussion Starter · #1 ·
I just found this site and registered and posted my first post to introduce myself. I look forward to learning and sharing on this site.
This post is about a problem I am having with my 4x4 and was hoping someone might be able to help me figure out the issue. I have a 2004 1500 Silverado Z71 with the 4 position electric button shift. I noticed that I had lost my 4x4 when I got stuck taking my boat out of the water on wet grass. I did some initial checking and found that the transfer case had no fluid in it. I filled it and then found a leak from the pump ring. The small hole was patched so I could determine if the transfer case was done. I lifted the vehicle off the ground and went through the positions for 4x4 and the wheels seemed to engage in every position, but the front wheels would turn faster than the rear wheels. The front wheels don't seem to grab when the truck is on the ground. Not sure where to look next. I also changed out the front axle actuator with another used one, but both seem to be working fine. I also tried to stop the front wheels from turning when they were engage off the ground, but I couldn't stop them. Is it normal for the front wheels to turn faster than the rear ones when 4x4 is engaged? Any tips would be much appreciated. I do realize that I will have to re-address the transfer case leak in the near future.
Thanks, Jim
 

· Supr Moderator AutoTech SS-Guru Mbr Extraordinaire
2015 High Country Duramax
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If they are truly spinning faster, then I'd check the gear ratios in the front compared to the rear. For the fronts to be going faster, the front ratio would be higher (numerically lower) than the rear.

And example of this would be say the truck came with 3.42 and someone changed it to 4.10 but didn't do the front. Of course that's just an example.

The front and rear should be almost identical in speed though. You will be a little different between the two, but not much.
 

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Discussion Starter · #4 ·
Someone mentioned to me that it might have to do with limited slip in the differentials if the front and back are turning at different speeds. I am going to disconnect the rear drive shaft to see if the front drive will move the truck on its own. I am not the original owner, I have had it for about 1 1/2 years. Lots of km on the vehicle, but well maintained. If the front won't move the truck, I would consider it the transfer case is the problem.
Will it indicate the gear ratio on the diff somewhere?
Thanks for the responses!
 

· Supr Moderator AutoTech SS-Guru Mbr Extraordinaire
2015 High Country Duramax
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Unless someone put it in there, GM never put a limited slip in their trucks.

You might have the G80 locking diff in the rear though. There is not locker or limited slip made for the front so that's definitely an open diff.

To find the gear ratio the truck came with open your glove box and look at the sticker with all the 3 digit codes on it.

GU4= 3.08
GU5= 3.23
GU6= 3.42
GT4= 3.73
GT5= 4.10
G80= LOCKING DIFF

Now that's what it came with, tat doesn't mean that's what is in the truck. The only sure fire way to know is to take the cover off and count the teeth on the ring and pinion and divide the two. There should also be number stamped on the ring gear that will tell you.

The front is harder to do that since there isn't a cover per say.
 

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Discussion Starter · #6 ·
Okay, so I deducted that the transfer case didn't put out enough torque to drive the front while under load. I put a so called rebuilt transfer case I found on line in and had to use my existing encoder motor. There are no codes showing on the dash, but when the electronic shift is put in 4x4 hi it goes into Auto. The auto 4x4 works, just wondering if anyone has any ideas of why it bypasses the command for 4hi and goes into Auto?
Thanks
Jimmer
 

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Discussion Starter · #7 ·
Thought I should finish this up for those that might be reading it and looking for answers. The transfer case I put in eventually started working fine and has been good ever since. Maybe the computer just took time to reset and recognize the new transfer case.
Jimmer
 
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