All-Mode T-Case

[GoPathyGo]

Ok, an initial search didn't bring up many hits, so posting here. Sorry if this has been addressed earlier. Wanted to get folks' opinion.

 

We put in a new, simple front driveshaft with U joints at each end on my '03 LE as part of the SAS. The LEs came with the All-mode transfer case that has 2-Hi, 4-Auto, 4-Lo and 4-Hi. IIRC, the all-mode has a clutch pack that uses the ABS sensors to figure out whether the front's losing traction and sends power to the front accordingly. We've bypassed the ABS pump since the Waggy front axle can't do ABS. We also have manual hubs on.

 

We noticed that the front driveshaft is spinning even in 2-Hi, causing a noticeable vibration. Take the driveshaft off and no probs. Put it in and hello vibrations and excess wear. Happens even with the hubs unlocked. Just seems to spin; no torque going to the front. 4-Hi and 4-Lo seem to work fine. Does the all-mode ALWAYS spin the front driveshaft, even if you're in 2-Hi ? Is this something I should be concerned about ?

 

TIA,

GPG.

[SteeevO]

If you get your driveshaft angles correct, you shouldn't have any vibrations.

 

I wouldn't worry about the front driveshaft spinning. Even in 2WD it may spin a bit at highway speeds.

[Simon]

It shouldn't always be spinning, however, given that you've modified the front end so much, it may "think" the front is slipping, and be trying to send power to the front wheels.

[GoPathyGo]

Simon, I wondered about that too. It'd make sense for it to spin a bit in 4-Auto given the whole "no ABS sensor" thing, but even in 2-Hi ? I wasn't sure if, with this case, 2-Hi got some spin courtesy parasitic drag.

 

Steeevo, thanks. The driveshaft angles *should* be correct, BUT I'll have them check again. Maybe if we compare it to a bone stock All-Mode LE we can be sure.

 

Maybe I can just drive around in a SASed Pathy with the driveshaft in the back seat, ready for me to bolt on when I go wheeling.

Edited April 20, 2010 by GoPathyGo

[5523Pathfinder]

Most likely, the all-mode system is trying to operate. If you have bypassed the system, it may still be looking for the front wheel speed input, and activating the transfer case to get them to spin. I think your best option is to swap in a older manual transfer case and off the electronics....

Edited April 20, 2010 by 5523Pathfinder

[shift220]

Shouldn't be any driveline vibrations unless something is off. I just got rid of mine that only showed up with the truck in 4wd. The u-joints had no play but were binding and causing trouble. It had trouble switching out of 4wd as well (manual t-case) but now its instant again like it was when stock.

[fleurys]

I'm thinking that the 2-4 Switch selenoid valve is sending the wrong signal to your TC... The front drive shaft should not turn in 2wd...so somehow it thinks it is in 4wd.... So either the 4wd dash switch is damaged/broken or the solenoid valve has something...

 

Check the resistance on the shift switch and 2-4wd solenoid valve...check the procedure here :

 

If worst comes to worst, you could simply pass a switch inside the cab that would control the signal you're sending to the 2-4 valve..then you would control when you engage or not 4wd...

Edited April 21, 2010 by fleurys

[GoPathyGo]

Great info. Thanks guys! We will check driveshaft angles and switches tomorrow. Any and all other info/suggestions welcome.

[Precise1]

Yep, I'm thinking it must be the electronics engaging the front. I don't know that year or electronics, but there doesn't seem to be any other answer for the front shaft turning. Is it possible to jumper the front ABS sensor so it think there is always perfect traction?

 

As for the vibration, I'd have to guess something is off physically. U joint angle causing a light bind, bad U joints, imbalanced drive shaft, too long, something of that sort.

 

Failing all else with Derek when he says go back to a TC without electronics. They are handy when working perfectly, but...

 

B