I have an 05, my 3 ACD lights have been on for awhile and I know my pump is out. The other day I got stuck in snow on an off ramp and noticed that not all my wheels were spinning at the same time (I was digging the car out and my girlfriend was gassing it ). Shouldn't all of them be spinning with an LSD??

 

You got an EVO stuck lol i have yet to even come close to getting stuck. I would think all the wheels should spin but not 100% sure.

 

Just cause the three lights are on doesn't mean your pump is done. It defaults to tarmac if its something other than the pump failing if the 3 lights are on. So if its in tarmac and its in the snow it may be doing something quirky as far as power delivery.

 

If the pump does go bad what would actually happen? Anyway ive always seen all 4 spin. Gl bro

 

I had the pump failure diagnosed by a Dealer.

I'm just not sure if this is normal. I don't think the ACD should have anything to do with it but I figured I would let you guys know the cars current state.

 

Well, lets look at the typical 4X4 pickup with open differentials. Stuck in snow the truck will display one wheel spinning and three doing nothing. So, the driver locks the transfer case. Now, she has two wheels spinning and two doing nothing.

When stuck in snow, to consistently get four wheels spinning simultaneously, the vehicle needs locking front, center and rear differentials that all lock at the same time. Then, if a manual transmission, you will probably fry the clutch. If an automatic you chance overheating and destroying the transmission fluid.

In deep snow it is better to have one or more tires spinning. This saves the clutch and helps dig the vehicle out. So, in this situation, having equal torque going to all four wheels is may not be the best solution.

 

ACD defaults to open. Means the diff is still 50/50 but wheels can spin independently front/rear.

LSD should see both front spinning though.

 

You probably don't have LSD

 

LSD lets your wheel with traction spin I think.

 

I have an 04 (no acd) and not all 4 wheels spin on the pavement

 

My Evo was stuck in the snow and the rear tires was spinning more the the fronts.

 

All 2005 USDM Evos have a front and rear LSD.
2003/4 GSR's do not have a front LSD.