drivetrain disengaging on steep ascents

[biggs85]

When I was on the Moab 2006 explorer run there were a few times when I would be going up a really steep hill and something in the drivetrain would completely disengage. I would roll backwards down the hill and put it in neutral and then drive and eventually it would engage back to all 4 wheels. I was then able to get up the hill without disengaging if I would go at a slighlty faster rate. I had been up the same exact hill several times in the past without ever having any problem at all. At first I thought it was the Powertrax No-slip locker that I installed about 5 months ago in the rear differential but then I realized that when I was on the steep hill, both the rear and front wheels had no power after something disengaged. So it has to be either the transfercase or the transmission. The explorer has about 180,000 miles and I don't really have any experience with transfercases or transmissions. Anyone have any ideas?

 

[410Fortune]

yes it sounds like your transmission was scavenging for fluid (sucking air)
You may have just been a bit low on trans fluid

the reason the 4x4 trucks have a deeper sump on the trans pan (hump) is for this purpose.
when I installed a custom aluminum trans pan on my old A4LD I ran into the same issue, especially in Moab on the launch pad, had to back down like 4 times...not fun.
I kept adding more trans fluid, eventually I made it but at this point my trans was over full.
The people who made my trans pan the re-designed them to fix this issue and sent me another one.

So check your tranny fluid, or have you installed any custom transmission parts or filters?

 

[biggs85]

So do you mean it could be the torque converter not getting enough fluid? I'll have to go and check the fluid after work but it almost sounds like it's something actually disengaging. It's not like its slipping or anything, it just seems like its completely disconnected. It would also make a quiet "snap" when it happened. The transmission is completely stock.

Also whenever I take off from a stop just around town it seems like the drive train is winding up and finally "clunks" into place.

 

[410Fortune]

yikes sounds like you have some trans issues starting to arise, possibly the converter, but first start by checking the fluid level.

I mean that when you get steep, the fluid in your pan is in the back, the sump (pick up tube ont he bottom of the filter) for the automatic transmission cannot suck up any fluid, or gets air pockets. This will cause the entire transmission to stop working as it is completely hydraulic, not just the torque converter.

It felt like I reached down and put the transmission in N right when I was revving and driving up the steep hill, yes it made a loud bang and I lost all gears, the engine would rev to the sky.

check your fluid condition and level.