Autotrac too tight

[Guest]

I'm a newbie so I hope I'm posting this in the right forum. My 99 Sierra 5.3 has 29,000 miles and until now you couldn't tell it was in Autotrac unless it was a tight turn on pavement. It always did as advertised and quietly until now. There is no difference that I can tell between Autotrac and 4WH on pavement. The dealer, without driving it, said they all do it and it is normal. Pulling out of a parking lot this morning the tires were chirping and the truck jerked around the corner. This isn't normal. Any ideas??  Thanks in advance.

[MountaineerTom]

First off, welcome to the site.  We hope you enjoy it.

 

I would go back to the dealer and request the technicial ride with you, that way you know if they hear/feel it or not.  I've had one ride with me a couple times and they were able to see the problem I had that they said they couldn not duplicate before.  If they give you any trouble, ask to see the service manager.  You could then always try a different dealer if you have one nearby.  I don't think that is normal.  Mine is nice and smooth when in Auto 4X4.

[Shaners]

It sounds to me that your Autotrac is staying "locked" in.  It should do what you say it does when locked in 4x4 high, but I don't think it should do it in Autotrac.  Ask the dealer if you could try a "new" truck in the same circumstances...  then you could compare...

 

BTW, welcome to the site...

[chevy4x4trucks]

Welcome to the forum.  Sounds to me like you are running in 4hi all the time.  That would give you a chirping noise and make corners very hard.  It's probably a computer fix.

[Zane]

Moving to light duty....  

[TxDoc]

I was wondering if you know if it is all 4 tires, for sure?

And, if you have a locking or limited slip rear diff, and how long it has been since you have changed the diff fluid?

[silverado man]

I have the same problem with mine it seems as if it is in 4hi the whole time.  I have the locking dif.

[Guest]

I'm now thinking that the truck hasn't been worked enough lately. Last winter was the last time it saw 4WD. Took it out on Kmart parking lot and did tight S's for a while and it is much, much better but not as loose as it was. Should there be any GM additive for the transfer case like is added to a limited slip rear? At 29k miles it shouldn't need any fluids anywhere.

[Shaners]

There was/is a TSB on the transfer case.  I had my '00 changed out to the new (I think it is blue" fluid).  I complained of noise/vibration in 4 high and they changed it and then changed it again after 500 miles.  It solved my problem with my 1500 Silverado...

[RyanbabZ71]

I try and run autotrac (auto or 4wd hi) at least once a month to keep the fluids flowing.  

 

Tonight was the first time in about a month that i used it.  It was raining out and when i left school i broke the rear tire loose so i figured why not.  Ran fine couldnt tell it was in auto.  

 

As for the blue fluid it didnt make any difference in how the 4wd ran when i had mine repalced last winter

[siume99]

Very interesting.  I might have the same thing going on with my 2001 Tahoe.  I was thinking it was my Firestone Wilderness LE's on the freshly blacktopped parking lot at work.  I only notice it when in a tight turn into a parking spot.  I never thought much of it.  

 

I never run in Autotrack, always 2HI.  The only time I run in Autotrack is when I want to mess around on a gravel road or mud slick.  Is there a dedicated fuse for the Autotrack?  If so would pulling it and reinacting the event be worthwhile?  I'm also used to a front wheel drive van that "pulled" me through turns.  I was also wondering with the tight angle of turn, that my rear wheels were pushing the fronts sideways a little.  If this were the case, would trying a tight turn backwards answer questions?  Same tire turning angle, but the fronts are now being "pulled" through the turn not "pushed."  I'd think this would help distinguish the malfunctioning Autotrack and just rubber grip.  

 

I'm just brainstorming right now.    I'll play with my truck tomorrow and see.

[Markeaux]

While Autotrac is engaged it is normal for some minor "stutter" or vibration to occur in the front end during tight turns.

[siume99]

Nice signature Markeaux!! :love:  :blush:   How do you like the AutoRide?

[Markeaux]

Thanks man!  I got the Autoride cuz I thought it might give the smoothest, supplest, ride possible - and it has not let me down!  However, if there is one negative it is that I would like to lower the rear to level it with the front (I do NOT want to raise the front) but there are no kits (well, so far anyway) that work with Aride ... it looks like the rear ride-height sensor legs might be able to be shortened or relocated to fool the system into thinking it needs to come down so I might give that a try.  Also, there was one guy who had like 50K mi on his Aride and said the ride firmed up terribly - maybe the shocks got locked into a firm mode or something - oh well there will probably be a price to be paid way down the line if I keep it.  As can be seen w/ my tire selection I am going for street/sport vs offroad -- and these tires are awesome in spirited driving in the hill country and at high speeds on the open road ... reminds me of the 98 Z28 that I traded in for this Hoe, well sorta LOL!  It is really cool that the Tow/Haul mode can firm up the shocks & keep the tranny in a lower gear longer which increases the handling+fun in the twisty bits.

 

I have had 4 other fullsize GM SUVs and 6 F-bodies plus some luxury cars and by far this is the best ever all-around vehicle.  But, now I need to get the TSB done to fix the rear window motors, neither will roll down now even if slamming the door (which was a quick fix for a while).