So who here's experienced in how the 4x4 works on 88-98 silverados ... I decided to park my front wheels on a curb at work the other day and they slipped over and into the grass a little. My rear wheels were on ice and the fronts were behind the curb somewhat ... try as I might 4x4 couldn't get me out. So a co-worker pulled me out .....

Question. Silverados with 4x4 and NO z71 package, they should have automatic locking hubs, right? Seems like I've never experienced this. In the snow down my street, I can get the wheels spinning on ice just like a 2wd truck and I'll go no where. I'm guessing maybe I don't have locking hubs? My truck has the floor shifter for the 4x4.

Also I changed the fluid in my differentials during the summer and only suctioned it out... so I've never set my eyes on my differentials. With that in mind, I spun my wheels when it was up on jack stands and they appeared to spin in a normal open differential way. Meaning, each wheel spins in opposite directions. I don't think I've ever had both wheels lock ... So I never added any posi additive.

So, does my '96 K1500 floor shifter have locking hubs or not? Sure doesn't seem like it does.

 

I can't speak for 88 to 98 but my 07.5 has a limited slip front axle and a locking G80 rear axle. Which means when I shift into 4x4 I'am actually powering one rear wheel and one front wheel.
Until I start to spin. Then the G80 rear axle will lock into possi making it a 3x4 drive

 

No you do not have locking hubs. Your hubs are splined directly to the CV halfshafts that go into the front differential assembly. The halfshafts turn all the time. There is a shift collar that dis-engages the RH(long)axle shaft in the housing. Sometimes the actuator does not have enough force to engage this collar with out being able to move or rock the truck slightly. Or the actuator could be bad altogether.

In2Trux, I am 99.99995% positive you do not have a limited slip differential in the front of your truck. It is just a open diff. I am not aware of any factory GM IFS truck that had any form of factory traction aid in the front axle.

 

For the lack of a better name... I was calling my front IFS a limited slip cause it would switch from left to right were ever and witch ever wheel could spin easiest.

 

So in reality, my 4x4 is really 3x4 unless I get some extreme wheel slippage and the collar locks in the other RF axle? Then at that point I have open differentials in the front and rear of the truck? I went through my RPO codes last night and looks like I have a 3.42 rear ratio, but I didn't see anything about posi or anything else of the sort.

Is there any way to manually activate/enhance this front axle lock in? Would a bad actuator throw a code in a module somewhere? How can I check this actuator?

 

The only way you will get 3 wheel drive is if you have the option G80, locking rear differential and have it in "4wd". The collar needs to be engaged to get front axle assist but is an open differential so will only power 1 wheel.

Over the years there has been several different types of manual axle engagement devices offered. What is available today I don't know.

To check front axle engagement one way is to shift into 4wd and jack the RF tire of the ground and try and spin it. If the tire turns the axle isn't locked in. Also try and turn the front driveshaft, it should not turn as the transfer case should be engaged.

The older GMT400s had a front actuator that used a heating element and expanding gas inside of some bellows to engage the front axle collar. That unit was prone to leaks and poor performance in cold weather. There is a newer "fast actuator" for the trucks as an upgrade, it was standard from the factory but I forget when it came out.

There are two, two wire connectors going to the front axle actuator. One is for the actuator and the other is for the indicator. Check for power and ground at both. My 2000 classic has the fast actuator and I have never had any issues with it. No it will not throw any codes, especially in a manual transfer case model.

 

Hmm I'll have to try that. I'm pretty sure my 4x4 works pretty good, but I really didn't know about the front axle lock in thing. What's really the point of that? is it to make sure the diff isn't constantly spinning? The CV axles are always spinning, so this is just to isolate the differential when the truck is in 2wd mode, right?

Now I say my 4x4 works good is because I get in some really deep snow, throw it in 4x4 and have amazing traction after. I mean the thing's a beast in the snow.

 

There is a cylinoid on the front axle that engages the hubs, and it is a common problem for it to go out. I had to put 2 on my dads 98 and it had less then 100,000 miles on it.

 

I have lockers front and rear on mine. If it is in 4wd all four tires spin, although only three spin when in auto four wheel.

 

Did you add the front locker?
What kind is it, ARB, E-locker?