NP246: 99-02 vs. 03-07
 

Anybody know what the differences are between the 99-02 and 03-07 autotraks? I will be buying a reman case for my 2000, was wondering if a newer version will work. I know the newer ones don't have the front shaft spinning all the time, and will shift out of 4wd under full throttle. Anybody know?

A NP246 is a NP246. the only difference in any of them is the ones behind a 4l60 and the ones behind a 4l80.

there is a difference though - with the front ds

mine is always spinning also and I wish it didn't like the newer ones

Ive never seen a difference. Weird. Even in the new process book they dont seperate by year.

for some reason the older ones have the clutch slightly applied all the time

Yea my front driveshaft always spins also...I want to do an AWD conversion anyway though :D

Seems like the 99-00s do it. With mine in park I stuck a pry bar in the front shaft and was able to turn it with quite a bit of force. Its really a bad design as it will wear out the chain, the u joints and the front diff and you don't even have to ever put it in 4wd. Not to mention the loss of gas mileage. I think the ultimate fix would be a 261/263 3/4 ton or 1 ton transfer case. They actually have a big syncronizer in there that physically disconnects the front shaft from the main shaft so there is no parasitic loss.

does anyone know if you can modify the 99-00 246's so they free spin like the later 246's?

Im gonna put a np243 behind my 80 when everything goes back together. Works just like the 246 but no clutches.

This is what I want to know. I know for a fact that my 05's front shaft doesn't spin, and know for a fact it shifts out of 4wd under full load when you push the button (track video to prove it). I am not really concerned with shifting out of 4wd, but hate that the whole front driveline is spinning on my frequent 3-400 mile trips when it doesn't need to be.