Hi All,

I have searched the archives a bit, but have not come across anything that looked like an answer. What I would like to know is what happens in the front diff of a Montero/Pajero equipped with Active Track/Super Select when 2H is engaged?

This is what I know (or at least I think I know <img src="/forums/images/graemlins/wink.gif" alt="" />):
1. The front wheels are attached to their respective front CVs and sideshafts (i.e. they rotate together).
2. The LHS sideshaft is permanently attached to the LHS side gear in the front diff (i.e. they rotate together).
3. The RHS sideshaft can be disengaged from the RHS side gear in the diff via the freewheeling clutch.

So does the LHS sidegear spin the spider gears in 2H, because the crown wheel is held stationary by the front prop shaft or would the crown wheel and front propshaft actually spin?

I hope I am making some sense and would really appreciate any input from the tech gurus.

Regards

Gerrit

As far as I know, the front shaft is stationary while the center disconnect pin is not engaged[2 wheel drive]. Your CVs,and drive axles are all together like you posted. Hope this helps you out.

In 2H the centre of the front diff disconnects.

One front wheel drives its cv/axle and centre of the diff, the other front wheel drives its cv/axle,ring and pinion of the front diff and front drive shaft.
The drive shaft is disconected in the transfer case from the rest of the drive train.

All the mechanical parts still spin, the diference being that the diff itself is disengaed so that there is no connection between the front left and right wheels. If this didnt happen the steering feels very "funny" while cornering in 2H

The only way to stop the whole assembly from spinning is to install manual hubs

Thanks guys,

So basically, when running in 2H the setup is analogous to a part time 4x4 vehicle running in 2WD with the hub locks engaged.

I suppose one would not achieve much of a fuel saving by running in 2H compared to 4H, so why did Mitsu give us the option? <img src="/forums/images/graemlins/rolleyes.gif" alt="" />

I can think of two possible reasons:

• Refinement. On my previous vehicle (Gen 2) there was a lot more whine and hum when running in 4H on the tar than in 2H. On my current Gen 3 I can not detect any difference in terms of NVH between 2H and 4H (Gen 3 has a different center diff).
  
• Wear of Center LSD. The center diff is a lockable limited slip diff (viscous LSD, I think) and running around corners on hard surfaces in 4H could lead to accelerated degradation of the (partial) locking ability of the LSD.

What do you guys think?

Regards

Gerrit

Just to add a little bit. I def notice a drop in gas mileage when i am in 2wd vs the 4wd or AWD mode. I drop about 3 mpg at least cause now power is being sent to the fronts...its different even though in 2H its still spinning and turning there is no power being transfered through the t-case.

When in 2WD, the front ring and pinion and the driveshaft that the pinion is connected to is stationary (does NOT spin). The only parts that spin while in 2WD are the hubs, cv axles and joints, and the spider gears within the carrier. The ring and pinion and drive shaft going into the transfer case do not move unless the freewheeling clutch is engauged which connects the right front wheel to the spider gears forcing the pinion to spin the drive shaft. That is how I understand it from a diff shop that just put my front locker in.

scottie

I concur

I thought that's how it worked, now I have to put my Montero on my rack at work this week and verify just what's happening underneath the vehicle. <img src="/forums/images/graemlins/smile.gif" alt="" />

BTW, that is why it is sooo very critical that when you put a front locker in a gen II montero with active track 4wd, the front locker can only be activated when the truck is already in 4wd. If you activate the front locker when the truck is in 2wd, you will blow up your t case b/c it will force your pinion to spin when your t case doesn't want it to b/c it not in 4wd mode. just a little fyi

scottie

you guys have got me curious, and I dont mean to hijack the thread, but - do all GenII's have active track? I have a baseline GenII is this a different kind of 4x4 system?