4x4 Problem

smoky1480 · #1 10-13-2005, 03:13 PM

I have a 2000 Blazer with on-the-fly 4x4. Awhile back while driving at about 50 mph (in 2 hi) I reached for something in the passenger seat. In doing so I accidentally hit the 4x4 button. It went in alright but with a fair amount of noise. I stopped fully and switched back to 2-hi. It did not want to but with a loud clunk it did go into 2-hi. Later I tried it again. From a full stop I pressed 4-hi and it went in smoothly...but does not shift gears...just seems to stay in low. I switched back to 2-hi. It went back in with the same clunk. Next I reset the computer and tried the same experiment again. Same result. Anybody have any suggestions?

firepaw · #2 10-13-2005, 05:33 PM

Smokey - I recently had a similar problem with the wifes '98. Thanks to the guys here, the problem is gone. I didn't buy the suggestion right away, like a dummy.

Check your TIRES. Yup, I said tires. If the front and back tires don't match in wear you'll get that "loud clunk" when the front diff finally disengages, especially on dry pavement.

Search the site a bit and you will probably find the thread. I put some new tires on and the problem disappeared. Think of it this way - the drive systen tries to turn the front and back wheels at the same speed. If the tires are of different sizes due to wear, the front and back wheels are actually trying to travel two different distances with the same RPM.
You can see how the load on the front diff would be different than that of the back. When that right front axle tries to disengage theres actually a lot pressure on the gears.

Check those tires, really. After that clunk is cured look into the shifting problem, if its still there.

T

smoky1480 · #3 10-14-2005, 07:41 AM

Thanks...what you say does apply because the front tires are much newer than rear ones. I wonder if that has anything to do with shifting gears. does not seem logical. I am scared I screwed up my 4 x4 but I hope I will be able to fix it with this groups' help.

BlazerLT · #4 10-15-2005, 01:06 AM

Quote:

Originally Posted by smoky1480

Thanks...what you say does apply because the front tires are much newer than rear ones. I wonder if that has anything to do with shifting gears. does not seem logical. I am scared I screwed up my 4 x4 but I hope I will be able to fix it with this groups' help.

Yes, the banging is from the tires not being the same size.

Always replace 4x4 tires in a set of 4. They all have to match.

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