I have a 2001 Limited with 33" tires and the 5-speed A/T.

I'm looking for information on regearing the differentials to get back to the standard drive ratio with the larger tires. I just started pulling a trailer and with the extra weight I cannot keep it in 5th gear and I'm getting around 10-11 mpg. <img src="/forums/images/graemlins/frown.gif" alt="" />

According to the OEM service manual the rear diff is 4.3 and the front is 4.3 for the 4-speed transmission and 4.9 for the 5-speed; however, I beginning to think that's a misprint and that I have 4.3 in both the front and rear.

Also, I have the LSD in the rear, but would want to convert to the OEM locker if buying a salvaged diff turns out to be feasible (I don't know how hard this would be to retrofit given the wiring, switches, etc).

Does anyone know if simply buying the 4.9 gears is possible and whether they would fit my diffs? Are there other 3rd party options for the Gen III trucks?

Any help or advise would be most appreciated.

Thank you,

Tony

Your front & rear diffs will always have the same ratio gearset in them. Check the dataplate under your hood which should tell you what gears you have.

Isn't an answer to exactly what you were asking but you can recover some HP by installing manual locking hubs on the front and leaving them unlocked when you don't need 4WD. If you're running AWD, shift the t-case into 2WD and unlock the hubs.

Edward

There is no way to install locking hubs on Gen 3. No easy way at least.
4.3 is for 5speed and 4.9 is for 4 speed. 4.9 are direct replacement for 4.3. You can get new R&P set from dealer or just get complete set of diffs from junk yard. They are bolt on.
Not sure which oem manual you are looking at but mine is pretty clear on that.

Now I'm thinking there used to be a typo in printed manuals subsequently revised in TSB.

Awesome. Thanks for the info. I've got some research to do now.

1. Determine if the 4.9's will really make that much difference over the 4.3's on 33" tires. I'm thinking about a 10-12% increase in RPM's. Probably get me pretty close to what I had.
2. Decide if I can find a used LSD or Lockable Rear Diff with 4.9's already in it--that would be the best if it's possible to retrofit it.
3. Decide if I should just purchase the new gears and wait for the ARB locker for the rear.

My book definitely has a typo. It's states the exact opposite.

Thanks, gentlemen, for the help. Great to meet so many Montero drivers out there. I thought I was lost on other forums full of Tacomas, LC's, Jeeps, and LR's.

Man, I feel really stupid now. I didn't know that gear ratio's were under the hood. I thought it was just timing, spark plug firing order, fluid specs, and stuff like that.

Learn something new every day. Okay, I learned a lot today.

Thanks again!

Tony

I do not think you will find a locking rear for a 3rd gen in country. I expect you will need to go overseas for that.
The spline count in a 3rd gen is different than in the 2nd, I have not measured the width of the carrier to see if they are the same. If they are close you maybe able to respline your inner stub axles and use the earlier diff. But I do not know the diameter of the 33 spline stubs to be sure this can be done.
The front should use the same diff sections as a 2nd gen so an ARB should be available.

stub axles are same diameter as Gen 2 large diff - 35.5mm. But have 33 instead of 31 splines. So resplining won't happen. None the less with front ARB and rear possibly best in class Hybrid LSD (if you source one altogether with diff or just reuse one you currently have) it will be very formidable.

Gentlemen,

I know it's been a while. I dropped this for a while for time/money reasons. But, I'm interested again in picking this back up.

Okay, so, I've found front and rear diffs from an XLS version. They should have the 4.9 gears that I want. Plus, I was able to find a rear carrier assemply with the OEM locker!

So, I need to know how these lockers are actuated. An out of town friend told me that his OEM locker on his gen II is air actuated. Since all OEM locker's I've seen (Nissan, Toyota) are e-lockers, I have to believe that Mitsubishi went this same route.

So, I'm looking for any help from anyone who has one of these or who knows how these work. What additional parts will I need?

Again, many thanks to all for your kind support.

Tony

AIR