This is my first 4x4 and my 7th (63 f100, 73 1500, 72 1500, 81 3500,73 250 390 & 03 f250 460 gas sold w/ 275k), truck. I hunt and fish and am not a rock crawler, grade 2 & 3 and rarely 4 off road{Death Valley, E. Sierras, the Mojave,SW deserts.
Question: I have an LS 3.55 4 spd auto o/d on the fly 4x4. When I put it in 4 Low, (not on the fly) I stop, put it in neutral, switch to 4 low and wait for the clunk and the idiot light to come on 4 low. Does this mean it is still in LS or is it locked? Are both diffs locked? I can't steer worth a dang unless I am in soft sand, gravel or snow. It sure feels like I am locked up, and all four wheels are churning and I seem to have lots of torque to the ground.( I have driven my brother in laws 4x4s with locking hubs and it feels the same.Question 2, My buddy swears he has a locking rearend in his 2x 2006 Colarado (non Z71/85), is it LS posi or locking?
Thanks.
regards,
PTC

 

Your truck has LS rear in 2 or 4wd and an open front differential in 4wd. In the best of situations you have 3 wheels giving power to the ground when in 4wd (two rear and one front). The LS rear will give power to both wheels up to the point where the LS clutches are overcome at which point any additional power will be given to the wheel with the least traction. Keep in mind this assumes the LS clutches are in good condition (I've read that the clutches are worn at 50K; I'm not sure I've had my truck in situations where I could tell if the LS was working or not). At no time is either differential "locked" in your truck.

When you say the truck feels locked, what you're probably feeling is the lack of differential between the front and rear axles (the difference between AWD and 4WD). When you turn, the front and rear wheels travel different distances so without a differential between them,the only way this difference can be made up is by the tires slipping. On a high traction surface, this can be destructive to the vehicle and should be avoided (your owners manual will say to use 4wd only on surfaces with poor traction).

I hope the above explaination makes some sort of sense to you (I just got off a night shift of sucking asphalt fumes and seem to be having trouble putting my thoughts into words). If anyone reading this sees something wrong with my explaination, please correct me as I'm still trying to get a full understanding of open/LS/locked differentials.

BTW, welcome to the forum. I was raised in Bishop and have explored some of the areas you mentioned.

Swansea


Coyote Flats

 

Thank you fairlaner.
A Jeepster offered a similar explanation, but yours was easier to understand. Today the Jeepster and I crawled underneath to look at the rear diff to see if it had a locker. There was an electrical connection on top of the pumpkin, which I presumed was a locker. Jeepster doubted it and said it may be a temp sensor (I have a tow package). I couldn't find anything on it in the manual.
Thanks again.