BOPOH
Explorer
I think 01-04 sport xls and limited had 4.9 diffs. I'd like to know that too if you cam swap ring and pinion from sport to gen 3
School Me on Rear Differentials - Gen 3 Montero
- Thread starter nnamssorxela
- Start date
Toasty
Looking for that thing i just had in my hand...
You can swap the 9.5" 4.90 R&P into a Gen 3 from a Sport but not the differential because the spline count is different. Also I'd like to point out that the hybrid LSD might not be worth the trouble if you're doing it for off-road traction. They work really well until a tire is lifted and after that they don't work at all. As soon as the load is gone it functions as an open differential and we all know how easy it is to lift a tire in a Gen 3.
They do work fantastically with all 4 on the ground (dirt roads, wet roads etc). I have one for my new '98 and I'm going to install one in the front as well.
They do work fantastically with all 4 on the ground (dirt roads, wet roads etc). I have one for my new '98 and I'm going to install one in the front as well.
haolepinoy
Incomplete Idiot
Oh my goodness, I can't believe I'm about to try to do this. If I'm wrong please don't roast me Mr. Toasty sir, or turn me into anything unnatural.
If the Mitsu LSD was simply a torsen-style LSD you'd be exactly right, but the "HYBRID" system that Mitsu used (and still uses on the Challengers, etc.) incorporates a viscous system as well as the torsen specifically for wheel lift situations. Under most low traction conditions the torsen gears keep everything instantly locked together, but in the situation where a wheel has zero traction (and thus the torsen is useless) the viscous unit comes into play. The former is a torque-sensing unit, the latter a speed-sensing. Pretty clutch thinking.
Here's an article describing the Challenger's LSD setup. Here's an article explaining different LSD setups, with a quick nod to how ahead of everybody else Mitsu is with the HYBRID setup. And combined with the NP+ traction control...about as good as you can get before selectable lockers.
Michael Brown
You followed me, so now we're both lost
Haolepinoy is right about the hybrid LSD, so you certainly are incomplete.
The main section of the differential is a Torsen gearset which will not get a torque difference in a lifted wheel scenario. Torque sensing units allow the torque on each side to be zero even if the speed is unequal.
This is where Mistubishi added a small clutch pack to one side to accommodate the speed sensing need where a tire is lifted. Essential the wheelspin causes the clutchpack to heat and engage a small amount of torque. Once the gears get torque bias, they take over so the clutch does not bear the load. You can see the layout in the picture below. Also, in the 03+ models with traction control, the ABS system can also activate the torque bias on the spinning wheel before the clutch starts to engage. In both cases, the torsen gears lockup very quickly to provide forward motion.
I have had a 4.3 ratio Hybrid LSD in my 2005 for the last 6yrs/70k miles. It has worked very well with my traction control and has not caused any issues. It comes in handy on snow/icy roads, slick mud, and several offroad adventures. It has worked in times where I have opposite corners off the ground. It may be redundant with the traction control, but I like the added assurance of a mechanical LSD in the rear. Best practice I have found is to center the opposite corners across the obstacle and provide a slow steady throttle input while the system engages. As long as 2 corners maintain contact, I can get traction.
The main section of the differential is a Torsen gearset which will not get a torque difference in a lifted wheel scenario. Torque sensing units allow the torque on each side to be zero even if the speed is unequal.
This is where Mistubishi added a small clutch pack to one side to accommodate the speed sensing need where a tire is lifted. Essential the wheelspin causes the clutchpack to heat and engage a small amount of torque. Once the gears get torque bias, they take over so the clutch does not bear the load. You can see the layout in the picture below. Also, in the 03+ models with traction control, the ABS system can also activate the torque bias on the spinning wheel before the clutch starts to engage. In both cases, the torsen gears lockup very quickly to provide forward motion.
I have had a 4.3 ratio Hybrid LSD in my 2005 for the last 6yrs/70k miles. It has worked very well with my traction control and has not caused any issues. It comes in handy on snow/icy roads, slick mud, and several offroad adventures. It has worked in times where I have opposite corners off the ground. It may be redundant with the traction control, but I like the added assurance of a mechanical LSD in the rear. Best practice I have found is to center the opposite corners across the obstacle and provide a slow steady throttle input while the system engages. As long as 2 corners maintain contact, I can get traction.
Michael Brown
You followed me, so now we're both lost
Also, the ratios in the US Gen 3 are related to the transmission used, not the years.
4-speed transmission = 4.9 ratio
5-speed transmission = 4.3 ratio
It just happens that the 4 speed was discontinued in the US after 2002. This makes the situation of the following:
01-02 XLS = 4-speed transmission = lever style transfer case (with boot) = 4.9 differentials (can have Hybrid/Hyblid LSD)
01-02 Ltd = 5-speed transmission = Electronic slide transfer case control = 4.3 differentials (can have Hybrid/Hyblid LSD)
03+ = 5-speed transmission = Electronic slide transfer case control = 4.3 differentials (open only) = Added traction control system
All of the differential assemblies for the US Gen 3 ratios are the same and can be swapped without removing the gears. Just bolt in the entire assembly of the ratio you want. It is common to use 4.3 for better fuel economy/highway driving and 4.9 for offroad/larger tires.
4-speed transmission = 4.9 ratio
5-speed transmission = 4.3 ratio
It just happens that the 4 speed was discontinued in the US after 2002. This makes the situation of the following:
01-02 XLS = 4-speed transmission = lever style transfer case (with boot) = 4.9 differentials (can have Hybrid/Hyblid LSD)
01-02 Ltd = 5-speed transmission = Electronic slide transfer case control = 4.3 differentials (can have Hybrid/Hyblid LSD)
03+ = 5-speed transmission = Electronic slide transfer case control = 4.3 differentials (open only) = Added traction control system
All of the differential assemblies for the US Gen 3 ratios are the same and can be swapped without removing the gears. Just bolt in the entire assembly of the ratio you want. It is common to use 4.3 for better fuel economy/highway driving and 4.9 for offroad/larger tires.
plh
Explorer
Any Hybrid LSD option for the front? I understand that the Pajero EVO had this? Can't be the only application....
Michael Brown
You followed me, so now we're both lost
I think that is likely to be a one-off application. Remember, the Pajero Evolution was a homologation special build. They designed a top of the line Dakar winning truck with all the features Ralliart could fit. Then they built just enough as production vehicles to meet FIA regulations for the production class. Hence you have what is nearly a prototype/race ready vehicle winning from the production class. Many companies have made similar FIA homologation specials which have development systems not used in the rest of the product line. This is why those vehicles become extremely difficult to maintain and find parts. Everything was a low production build of high performance components for this one vehicle so it could dominate the race it was designed around.
As far as I know, there was never a factory hybrid for the front differential in the Gen 3. Not that Ralliart didn't have some in the Gen 3 Dakar trucks, but I have never seen one in the US.
Traction control systems in 03 made the hybrid diff an expensive alternative for the same problem. I would also think that the system may cause trouble in the front diff under extreme articulation/steering input combinations.
There was an air locking rear differential for certain remote locations (Africa/SE Asia) that was sold, so there may have been a front differential solution supplied with these?
I think that they found the front systems unnecessary in development so it was not implemented in most cases. Even the air lockers on Gen 2/2.5 are only installed on the rear axle.
plh
Explorer
IIRC, the front differential internal carrier guts in a Gen 3 are the same 8" components used in Gen 1 (V6 5 speed) Gen 2 (SR & 5 speed) , 2.5...
How about Galant VR4 AWD? Eclipes AWD? 3000GT VR-4? Lancer EVO? I'm not familiar with these thou. I know about the clutch pack LSD Starion 8" option. Torsen style hybrid would be better in a Gen 3 front.
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Michael Brown
You followed me, so now we're both lost
The front is an 8" gearset, but I do not know if the bolt pattern for the ring gear is the same. I do not have enough experience with the Evo/VR-4 diffs to know for sure. If someone could open an 8" rear LSD to check the measurements against a Gen 3 front differential then we could check feasibility. Both should exist somewhere, but probably not in the same forum.
plh
Explorer
8" rear from which vehicle, EVO/VR4?
