School Me on Rear Differentials - Gen 3 Montero

[nnamssorxela]

Hello All,

I think I've figured most of this out, but I'm still stumped on one part. I have an '03 Montero with the 5 speed and 3.8L motor (and traction control). From what I understand, I have the 4.30 diff ratios front and rear. My goal is to eventually run 4.90 with LSD rear, but I realize this is a "two part" project (for me at least)

From what I understand, the 01-02 Montero XLS had the 4.90 ratio front and rear open differential, and the 01-02 Montero Limited had the 4.30 ratio rear hydrid torsen LSD.

-If I just want to change to 4.90, I can grab front and rear third member (unbolt driveshaft and axles) from the XLS and swap them into my car.
-If I just want to change to a rear LSD and keep my 4.30 ratio, I can grab the rear third member from the Limited and swap it into my car.
-If I want to swap to 4.90 ratio AND LSD rear I can put a 01-02 XLS third member in the front OR put the 4.90 ring and pinion IN my original third member housing which will require setting up gears for the latter option. In the rear I have to pull apart the LSD from the 01-02 Limited and put in the ring an pinion from the 01-02 XLS and install into ANY of the gen 3 rear third member housings (requires setting up gears).

The part I'm unsure of; can I just swap over the 4.90 ratio R&P to the 4.30 sets, or is that not possible with the Mitsubishi diffs?

TIA,
-Alex

 

[KyleT]

4.90 was only in the 4 speed trucks. I would do the 4.90 and LSD diff. Totally bolt on and easy. Vs messing with swapping the carrier. Just be patient and find one to get both diffs from. Edit I mean just swap the whole diff case complete. Replace a few seals and fill
With oil. No mess resetting up gears.


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[nnamssorxela]

Kyle - I was not aware that the LSD ever came as a 4.9 in the US market? I thought the 01-02 (all 4 spds) had either open 4.9s or LSD (rear) 4.3 depending on whether it was a limited (sunroof) or XLS. All 03+ came with the 5 speed and open 4.3.

EDIT: I think my lingo is off. When I say "carrier," I mean the complete housing that is bolt in, vs the diff itself which needs to be set up.

I was going off an image posted in this thread that shows the LSD as a 4.30 ratio. Not sure if that image is even from a Montero though. http://forum.expeditionportal.com/threads/53206-Need-gearing-and-locker-info-3rg-gen-montero

 

[jeep-N-montero]

Kyle - I was not aware that the LSD ever came as a 4.9 in the US market? I thought the 01-02 (all 4 spds) had either open 4.9s or LSD (rear) 4.3 depending on whether it was a limited (sunroof) or XLS. All 03+ came with the 5 speed and open 4.3.

EDIT: I think my lingo is off. When I say "carrier," I mean the complete housing that is bolt in, vs the diff itself which needs to be set up.

I was going off an image posted in this thread that shows the LSD as a 4.30 ratio. Not sure if that image is even from a Montero though. http://forum.expeditionportal.com/threads/53206-Need-gearing-and-locker-info-3rg-gen-montero

They are usually called 3rd members, easy to remove as needed.

 

[Michael Brown]

The entire 3rd member/carrier is easy to swap, and can be done in a driveway with a jack and helping hand. I swapped a 4.3 LSD diff into my '05.

I have heard rumors that there were 4.9 LSD gearsets made, but I have never seen one in person to confirm. If you want to switch to 4.9 gears, your traction control will function like a limited slip whenever a wheel is slipping. It has been more than adequate for my front diff when wheeling.

 

[nnamssorxela]

I've edited my original post to make more sense. Since I don't believe I'll find a 4.9 LSD in the US, my original question still remains; can I simply swap the 4.9 ring and pinion over to the LSD?

 

[KyleT]

All 4 speeds are 4.90, all 5 speed is 4.30

I’m 99% sure the LSD was available in both gear sets. Standard on the limited and as an option on the XLS


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[plh]

I'm 100% sure the LSD was available in both gear sets.

 

[nnamssorxela]

Thanks all.

I lucked out and the only Montero at the junkyard was an '01 XLS with sunroof (seems to be tired to the LSD?) and the 4.9 LSD. Both diffs were very leaky, so I'm hoping there's some oil left in there and no damage. I'll be replacing the rear pinion shaft seal, and I may just replace all the seals.

 

[KyleT]

Should be empty of oil at the junkyard.


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[nnamssorxela]

I suppose I mean that the oil has clearly been leaking for some time. Hoping that there is even just a slick inside vs sludge and burned bearings or chipped teeth.

 

[haolepinoy]

Question regarding replacing the carrier output seals since both of mine are slightly weaping: is there any special steps or things to consider before simply removing the driveshaft and popping in another one? On my Cherokee there is a crush sleeve inside the pinion assembly that is "supposed to be replaced" when you remove the yoke nut. Failure to do so can cause the backlash to be off during reassembly. Just wondering if there any hidden considerations like that on the Montero?

 

[nnamssorxela]

Looking at the FSM, that appears to be the case here as well, and the sleeves and bearings are marked with an "N" indicating they need to be replaced.

 

[plh]

Looking at the FSM, that appears to be the case here as well, and the sleeves and bearings are marked with an "N" indicating they need to be replaced.

Interesting. I don't see the marks (N) for the sleeves and bearings for the Gen 2 Locker (I'm in the middle of putting once together is why the reference). The (N) is on the pinion nut, pinion seal and copper crush washers for the locker air line only.

Maybe Mitsu changed the sleeve in the Gen 3 to be the crush-able type.

EDIT: I looked at the '06 FSM and neither the sleeve nor bearing are marked (N). There are 2 different sleeves (lengths) shown, which one chosen would be dependent on which pinion depth would be needed.

 

[nnamssorxela]

The bearings are marked to replace, but I don't know if 13 and 19 need to be replaced if you are just pulling the front companion flange.

EDIT: I incorrectly assumed there were sleeves, but those are the bearing races.