Auto 4WD question

[gmtech4]

With the truck in 2whl, only thing up front turning should be the halfshafts. My understanding is that with auto engaged, the axle, diff and driveline are all spinning. So basically everything that would be spinning in full 4whl is going, except there is no power to any of the front, until the truck decides to send it there. A drop in fuel mileage makes sense, as there's a lot more connected to the front wheels, which the rear wheels now have to push.

 

 

did you not read what i posted???

 

i dont post to read what i said later ,

 

in 4 auto there is NO front output of the transfer case untill the modules sense wheel slip and the encoder motor applies a clutch inside the t case almost instantly locking the chain and you have 4wd ....along with front actuator already engaged as i mentioned

 

you are wrong,when in 2 wd the front diff actuator is disconnected the left front cv shaft does turn and moves the spiders inside -NO input ,,,,right front is turning to the shaft collar only(no spider connection)

 

you almost got it right but worded it strange i think

[RockySierra]

The problem with using Auto 4WD on a frequent basis in snow is that it does wear out those clutches, your better off using full time 4WD when the roads call for it. I've heard of several occasions of this happening, and it's a $1000 or so repair. Just some food for thought for those of you who want to keep your truck for awhile.

[kstruckcountry]

With the truck in 2whl, only thing up front turning should be the halfshafts. My understanding is that with auto engaged, the axle, diff and driveline are all spinning. So basically everything that would be spinning in full 4whl is going, except there is no power to any of the front, until the truck decides to send it there. A drop in fuel mileage makes sense, as there's a lot more connected to the front wheels, which the rear wheels now have to push.

did you not read what i posted??? i dont post to read what i said later , in 4 auto there is NO front output of the transfer case untill the modules sense wheel slip and the encoder motor applies a clutch inside the t case almost instantly locking the chain and you have 4wd ....along with front actuator already engaged as i mentioned you are wrong,when in 2 wd the front diff actuator is disconnected the left front cv shaft does turn and moves the spiders inside -NO input ,,,,right front is turning to the shaft collar only(no spider connection) you almost got it right but worded it strange i think

 

Lol yeah, I shoulda stuck to just saying no power to the front

[gmtech4]

The problem with using Auto 4WD on a frequent basis in snow is that it does wear out those clutches, your better off using full time 4WD when the roads call for it. I've heard of several occasions of this happening, and it's a $1000 or so repair. Just some food for thought for those of you who want to keep your truck for awhile.

 

 

there have to be at least 7 or 9 fibers in that clutch pack,i was thinkin the same thing and about how far the (clutch apply fork) almost proper name lol has to travel to compress that clutch pack

 

i agree ,about what ^^^^ said

[j13smiley]

For any of the GMT-900 owners, you need one of these:  http://www.gm-trucks...l=&fromsearch=1

 

I have one and really like it.

 

 

this... i'm very happy with mine!

[jvbronco]

For any of the GMT-900 owners, you need one of these: http://www.gm-trucks...l=&fromsearch=1

 

I have one and really like it.

 

 

this... i'm very happy with mine!

 

 

The linked thread seems to be dead (no posts in a while).. does anyone have info on these light installs. I would be very interested.

[j13smiley]

here's the newer thread...

http://www.gm-trucks...2

 

here's chris' sales page... (new module is 100% plug and play, no more wire splicing like the install video part3 shows).

 

http://polymotoengin...m/4wdlight.html

[RockySierra]

It is an awesome product. I do have a small issue with mine with the light in the dash staying on for a few minutes after I shut the vehicle off (even if it is not in 4WD) and am going to be working with Chris on this. I already made him aware, just ran out of time a couple of months ago to further troubleshoot with him. Mine is the older one, I got about 2 years ago but installed it back in September.

[Z45]

The problem with using Auto 4WD on a frequent basis in snow is that it does wear out those clutches, your better off using full time 4WD when the roads call for it. I've heard of several occasions of this happening, and it's a $1000 or so repair. Just some food for thought for those of you who want to keep your truck for awhile.

 

 

Baloney, I been driving with AUTO 4wd vehicle for years and years and never wore anything out. I asked friend who is a GMC tech how many TC's he seen with worn out clutches and he said NONE.

 

AUTO is there for a purpose, use it and never mind worrying what happened to someone else, might happen to you.

[RockySierra]

You can say baloney all you want, son. Doesn't change the facts. Go to any good repituble repair ship, axle shop, 4X4 shop, and ask them about it and you'll hear all about it. Take into account this is happening on vehicles that have been on the road for awhile, not the newer ones that most dealerships work on.

[00Silverado4x4]

How long is awhile then? Mine is going on 6 years & 90k miles. Just changed front diff fluid last month. No problems to date.

[RockySierra]

Beats me? I'm just re-posting what trusted sources have mentioned regarding the auto 4WD systems on GM and some of the other manufacturers transfer case system. For my previous trucks that had the system, I hardly ever used auto4WD. If the conditions were bad enough, it was in 4WD. With my current truck (2500HD) there is no auto option, not that I would use it if there was. Not after what I've read about and have been told regarding the clutch system in the T-cases. The last thing I need to do is to spend upwards of $1300 having one replaced/repaired. I would assume that as long as you don't abuse your system and do maintain it, it will get you by.

[jvbronco]

Great, thanks!

[speeddemon_383]

The auto can be a dangerous thing to use IMO. Right after I got my truck(same day) I was driving on snowy roads....and going a little too fast for the conditions on a curvy road. I might also point out that I was used to my 03 SS which kicked ass on snowy roads but regardless I was still going to fast.

 

Anyhow I was going into a curve with my truck in auto 4wd and it just kept heading for the guardrail. I had to hit the gas so the back tires would break loose to make it kick in. After that I put it in 4hi and left it there. The only time I would use auto now is if I was in a situation with questionable traction at low speed but thats just me. My dad always told me to drive in 2wd so when you got stuck you could get out and turn around, it is a good point if you get stuck in 4WD your options for getting out are limited...

[gmtech4]

The auto can be a dangerous thing to use IMO. Right after I got my truck(same day) I was driving on snowy roads....and going a little too fast for the conditions on a curvy road. I might also point out that I was used to my 03 SS which kicked ass on snowy roads but regardless I was still going to fast.

 

Anyhow I was going into a curve with my truck in auto 4wd and it just kept heading for the guardrail. I had to hit the gas so the back tires would break loose to make it kick in. After that I put it in 4hi and left it there. The only time I would use auto now is if I was in a situation with questionable traction at low speed but thats just me. My dad always told me to drive in 2wd so when you got stuck you could get out and turn around, it is a good point if you get stuck in 4WD your options for getting out are limited...

 

 

you didnt know how auto worked then rite?

 

at least you learned something with your drawers full of poop lol and no harm to the truck

 

i have and love my 2wd truck in the winter empty,driving by my butt is awesome and worth learning imo