Z71 Transfer Case Control

Y2KZR2 · January 18, 2002

Hello all. I followed Zane down here from the Corvetteforum because I have a truck question.

I will soon be buying a Z71. I drove two different trucks last Saturday. One had the push-button transfer case and the other had the floor lever. My 2000 ZR2 is pushbutton too but I actually liked the lever. Anyone else here have the lever on the tunnel and are there any advantages for either?

Also, does anyone know when the 2003's will be available for order?

Thanks all,

Randy

chevy4x4trucks · January 18, 2002

I've got the lever on mine. 1st advantage is it's cheper. 2nd is that less electronics normally mean less problems. Either way makes no difference. Some people don't know when to use 4wd so the computer does it for them. You can even have bucket seats and a floor console w/ a little bit of modifying.

Welcome to the forum.

MountaineerTom · January 18, 2002

Some people don't know when to use 4wd so the computer does it for them.

That's only when you have Auto-Trac engaged. When your in either 2WD, 4HI, or 4LO, you stay in that mode until you change to another.

I have the push buttons and have not had any problems with it.

Welcome to the site.

01z71 · January 18, 2002

I have a friend who had a '95 Dodge Ram with the manual pull bar lever. It was always making grinding noises going in and one time (He was already stuck) but could not pull it into 4wd.

I leased a '98 z-71 an now have purchased a '01 z-71 and have the electronic buttons on both. I have never had any problems with the electronics and would recommend it to anyone. It's just easier in my opinion. I know alot of people that swear by the manual lever though.

Shaners · January 18, 2002

Correct me if I'm wrong, but even if you have the lever, there are electronics that engage the front drive shafts.

So if you have the extra money, then I'd go ahead and get the pushbutton 4wd and enjoy the convenience of pushing the button along with the extra floor space for the occaisional third passenger upfront.

CityTruck · January 18, 2002

In my case I'm getting a regular cab and I'm married with one child. The car seat has to go in the passenger seat (seat anchors are there) so my wife will have to ride in the middle. The floor lever would make the center seat just a bit less comfortable (especially since the tunnel and cupholders are already in the way). Plus I really like the autotrac that engages the front wheels automatically when the rear wheels slip. Just my opinion though.

Kansas Kid · January 19, 2002

First I have some questions for you. How reliable do you want your 4wd system to be, and how long do you plan on keeping the truck?

If I was in your situation, and actually found a truck with the lever shift transfer case, I would buy that truck without hesitation. I wouldn't even consider buying a truck with the push button setup. Why you might ask. The lever shift transfer case is much more reliable then the push-button transfer case. You pull on that lever, the transfer case is engaged. Second reason being that the push-button transfer cases are very expensive to repair once out of warrenty. And more then likely, it will need repaired once out of warrenty. I know alot of people really love their autotrac setups and don't like to hear bad things about them. But the people who work on these trucks have given this setup its own little name....

Y2KZR2 · January 19, 2002

That's what I was getting at. Like I said, I had the pushbutton system in my 2000 and had it in my 1998 ZR2 as well. It worked fine but I always wondered about durability anyway. I intend to keep the new truck 4+ years unless there is an unbeatable deal down the line. Engaging by pulling the lever felt different than by pushing a button. You could really feel it pop in and not just the clunk from underneath like the button gives you. They certainly are accomplishing the same task. I guess you'd call it "feedback" of sorts.

Thanks for the replies!

Randy

Shaners · January 19, 2002

I've had several 4wd trucks, and the only one I ever had trouble with was my S-10 (it had the lever). All the other trucks were pushbutton and I never had any trouble.

I think you are safe with whatever system you decide. Some people like the "macho" lever sticking out of the floor, and some could care less about it. Either way, both systems have about the same reliability...

MountaineerTom · January 19, 2002

The way I see it, the push buttons themselves would be just as reliable as any other electronics on the truck. (Radio, a/c / heat controls, locks, windows, etc.) Just a matter of preference I guess. I'm happy with my push buttons, and I'd be just as happy with the lever. Doesn't matter to me.

Now I've probably jinxed myself, and all of those will go out on me.

Stepside Z · January 19, 2002

I have and prefer the lever. I think it is more durable overall and reliable in cold weather. Now if we could just get some manule hubs I would really be happy.

THE BIGPUNN · January 19, 2002

i prefer the pushbutton. never owned the manual shift. my friend has a '01 ram, and when he shifts, he has to completely stop and gets all this grinding sound, supposed to be okay. pushbutton is also easier for your old lady, and you can tell her just to use autotrac on bad roads, instead of explaining the whole thing to her.

TxDoc · January 20, 2002

Just some more opinions:

There are major differences in the shift mechanisms and internal operation of the manual and AutoTrac transfer-cases. The front axle engagement (center axle disconnect) is the same on both trucks.

When you select 4WD on the manual system by moving the lever, a switch will energize the front axle actuator causing the axle to engage. The movement of the lever shifts the transfer-case providing power to the front drive shaft. There is no way to engage the front axle without engaging the transfer-case. The shifting of the axle can have a slight delay.

When you select 4-HI (not Auto) in an AutoTrac equipped truck, the same basic process takes place except the transfer-case is shifting through an electrical actuator. Once again there can be a delay. But, when you select Auto the front axle engages and the transfer case remains in 2WD (the hubs locked and the transfer-case in 2WD). Once it is in Auto, if the system detects wheel slippage the transfer-case will apply power to the front drive shaft placing it in 4WD. Also when you are in Auto, if you decide you want to be in 4WD, you simply press the 4-HI button and the transfer case will engage without having to wait for the axle engagement because the axle is already hooked up.

The way the two cases shift internally is different. The AutoTrac system is shifting on the fly so it needs to somewhat gradually apply power to the front drive shaft. It uses a multi-disk clutch similar to clutch packs found in an automatic transmission. Where the manual case uses a sliding clutch like you would see in a manual transmission

(from Dougmac)

I read your previous posts on this issue and I understand your concern about the electronic shift servomotor and speed sensors being in a location where they are exposed to the elements.

If you order a manual shift system you still have the servomotor that engages the front axle under the truck in the muck. If you have an automatic transmission, you have an output speed sensor on it. They all have antilock brakes, so they have four wheel speed sensors mounted at each wheel end. And a bigger concern is the $1500.00 antilock brake controller that is mounted on the frame next to the transfer case.

If you plan on submerging the undercarriages of any new truck, you are guaranteed to have problems with them AutoTrac or not. Not to mention, water damage to wheel bearings, CV joints, U-Joints, transfer-case, and differentials.

Push button or manual lever does not effect the speed of 4x4 engagement on the newer chevy trucks. The older (i.e. my 93)used a solenoid to lock the front diff, which was very slow, especially when cold. The lever is only engaging the transfer case, the solenoid in turn is locking the front diff. A few years ago (I forget the year), GM started to use a motorized enagement device that engages the front diff very quickly, with push button or lever. The older style can actually be upgrade for about $100-odd dollars in parts.

(Dougmac)

I stand corrected there are two wheel speed sensors in the muck not four. The front axle "Electric Motor Actuator" (term from the service manual) is in fact a servomotor. From Webster's Dictionary.... "servomotor" a power-driven mechanism that supplements a primary control operated by a comparatively feeble force (as in a servomechanism). The device that shift the transfer case is also a "servomotor".

Now that we have that out of the way, maybe you can understand my point. There are many electronic and mechanical components under these trucks that can be damaged if the vehicle is not treated with some degree of care. If you eliminate the transfer-case sensors and "servomotor". You have not changed the fact that there are equally sensitive parts still under there.

(Dougmac)

Remember that push button and "auto-trac" are two different systems. Regular push button is the same as manual lever, only it cleans up the floor and is a little more convenient. AutoTrac, which is not available on the HD's with Allison, keeps the front diff locked when turned on, but no power is applied to the front until slip is detected at the rear. When slip is detected, the system kicks in power immediatley to the front diff, which is already "locked". It is extremely fast and works well. I just used it last night at the bottom of my driveway, which is ice covered. I barely detected the slip in my rear wheels and the front kicked in instantly

(from LeeKim)

MountaineerTom · January 20, 2002

Are those quotes from the people who are listed in parenthesis?

TxDoc · January 20, 2002

Yes, Tom. Wanted to give them credit for their info. I don't think I have heard of anyone having any problems with the AutoTrac. I never had any problems with my InstaTrac, either.