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Everything works except 4wd Low

JrBean

Full Member
Joined
Oct 3, 2014
Messages
24
Location
Charleston, IL
Hi! My 2006 Avalanche will no longer shift into 4wd low. All of the other modes work fine. I put the transmission in neutral while the truck is in one of the other settings. I allow the truck to roll  very slowly down the drive and press 4wd low. The light flashes and the  normal clunking sounds forward and rear can be heard. Then the light quits flashing and it returns to whatever mode it had been in before.

I'm not a mechanic. I just would like to know if this is a potential transmission starting to go bad, or if it sounds like something related only to 4wd low?

Dumb it down for me. :)
 
Try it going forward.
 
The good news is that 4-Wheel LO is not transmission related.

HI/LO is determined in the transfer case.

Out of curiosity, do you ever have a real need for the LO setting?
 
Nick@Night said:
The good news is that 4-Wheel Lo is not transmission related.

Hi/Lo is determined in the transfer case.

Out of curiosity, do you ever have a real need for the Lo setting?

That is good news, thanks!  Very rarely... which is why I asked.  I figure as long as 4hi works, and my transmission is till working good, I'm just going to ignore it.  I think in the two years of owning it, I've actually used 4lo one time, in the snow, when I was either stuck or trying to get someone else unstuck.  I'll have my mechanic give me his opinion on the problem/solution the next time I get it in there for some reason.

Thanks for your help!
 
That sounds like a good idea, because just as hard as it is to put it in 4Lo it is just as hard to get it out of 4Lo. After 13 years of ownership mine was only in 4Lo 1 time and that was because the control module went bad and it shifted into 4lo by itself.
 
I was running my 4-wheel modes through their paces, around Thanksgiving.

LO seemed to be slipping, so I changed the transfer case fluid over Christmas break.  Haven't tested LO, yet.  HI & Auto, smooth as glass.

 
And remember Don't use 4wd on dry pavement especially while turning........only off-road or in slippery conditions.
 
JrBean said:
Hi! My 2006 Avalanche will no longer shift into 4wd low. All of the other modes work fine. I put the transmission in neutral while the truck is in one of the other settings. I allow the truck to roll  very slowly down the drive and press 4wd low. The light flashes and the  normal clunking sounds forward and rear can be heard. Then the light quits flashing and it returns to whatever mode it had been in before.

I'm not a mechanic. I just would like to know if this is a potential transmission starting to go bad, or if it sounds like something related only to 4wd low?

Dumb it down for me. :)

  Do have an owners Manuel? If I remember you should be stopped place in neutral,
press 4low let engage, then start your travel. The electric controlled T-case and
front diff have safety feature built in. 
 
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