Montero SR ear Air locked Axle Tech thread

[Gravy]

I picked up a fullsize Montero SR rear axle a while back because I thought it was cool and I'm thinking about possibly swapping it into a Toyota buggy that was breaking rear R/P's.

Tech that I know about it:

-5" diameter 4 bolt flange vs. 4" diameter 4 bolt flange (Toy)
-9.5" ring gear.
-6x5.5 bolt pattern (Toyota, GM, etc...)
-disc brakes.
-4.632 gears [should be an ok match for 4.56's in a trail rig? (1.55% difference)]
(I imagine I could swap out the ring and pinion with a set of 4.90's from an open diff)
-Only 2 pinion bearings unlike the 3rd bearing on the pinion snout of a Ford 9".
-setup for coils/ links (easy to fix with my plasma cutter)
-Third member with Factory Air Locker (I could engage it with like 15-20psi)
(found this Youtube video)
YouTube - Montero differential Air locker
-31 spline axle shafts are identical in spline depth and pitch to a Ford 9" stock 31 spline axle shaft (I slid one in)
-I pulled it apart before I measured the wms to wms width, but it seemed narrow enough to work.


Seems like it would be a good upgrade for a Toy.
What says Pirate4x4?
Should this axle hold up to a "mildly built" 22re with twin cases and 38" SX's?
How beefy is the locker?

Please add what you know.

[BlueMontero]

Here's guy who mixed the two. Smaller 28 spline parts but you get the idea.

http://www.outerlimits4x4.com/viewto...ord+9#p1686779

On the same board those guys are breaking the earlier 9" 30 spline axles all the time, but dont know of the 9.5" 31 spline ever breaking.

I've never managed to break the smaller axle in my grossly overweight montero before so I say go for it.

[sneakyninja]

Get the factory pump from a salvage yard they wire up easy and just need an on off switch. I think they engage closer to 6psi, putting too much pressure can damage the diaphragm. I think this axle will be a great swap for a toy, do it and put some fat tires on it!

[Gravy]

anything else on these?

[Guns_and_Roses]

Originally Posted by Gravy

anything else on these?

i run one in my rig on 33's and it works perfect. i am going up to 35's and i have seen others use 37's with no problem either.

Run it over the Rubicon , dusy , mohave , the hammers and more. it has never failed me once.

it is a very tough rear end.

the axle bearings are difficult to remove if one ever goes bad just so you know. no way to do it on the trail.

[sneakyninja]

Don't try to engage the locker while spinning tires (obviously) but that's the only thing i've seen break on them is actuator teeth shearing off while engaging the locker during wheelspin. It seems like a no brainer but a few people have done it, the good thing is at that point you just have an open diff and you can still drive it home. The ARB air locker should beef up the axle if you need it but the locking third members are inexpensive and super tough so i'd try and break a few of them before upgrading.

I'm going to run 40's on my '94 montero with dual T-cases and i'm not too worried about breaking anything on the rear end. i figure since my axle has held up in my '99 which has crawler gears and is a lot heavier than my '94 (chop top) it'll be fine. I'm pretty sure the shaft splines are forged on this axle too, shafts and pinion.

[Stick L200]

The rear factory lockers operate at 6psi. An aquarium tank pump has the power to operate the locker if you can find a standard pump.

[CRAPTACULAR]

I thought they had 4.636 gears.

[sneakyninja]

They come in three ratios, 4.27 (98-00) 4.63(93-97) and 4.90(3.5 powered montero sports). 5.29 can be made to work from the mitsu 9" rear the write up is on outerlimits4x4.com link to the write up

[Guns_and_Roses]

Originally Posted by sneakyninja

They come in three ratios, 4.27 (98-00) 4.63(93-97) and 4.90(3.5 powered montero sports). 5.29 can be made to work from the mitsu 9" rear the write up is on outerlimits4x4.com link to the write up

would be nice to get the 5.29 in the the front dif.

[Gravy]

Originally Posted by sneakyninja

They come in three ratios, 4.27 (98-00) 4.63(93-97) and 4.90(3.5 powered montero sports). 5.29 can be made to work from the mitsu 9" rear the write up is on outerlimits4x4.com link to the write up

To my knowledge the Montero Sports never had an airlocked rear, but I'm told the 4.90 ring/ pinion can be swapped to an airlocked third member.

[sneakyninja]

I was just pointing out available gear ratios but the sports had air lockers from 97-99, they are the leaf sprung axles and some of the big axles are even 34 spline in those, don't know how to tell which ones are the 34 spline so if you get a sport axle just plan on not being able to interchange anything other than gears with other montero axles.

[Raole Duke]

Originally Posted by sneakyninja

I was just pointing out available gear ratios but the sports had air lockers from 97-99, they are the leaf sprung axles and some of the big axles are even 34 spline in those, don't know how to tell which ones are the 34 spline so if you get a sport axle just plan on not being able to interchange anything other than gears with other montero axles.

The Sports with a locker are rare, if not entirely out of country. I saw one on monterosportonline a long time ago, I think the guy was from Australia. Here I think all we have is LSD. Never heard of the 34 spline axles, I know the 2.4/3.0 had 28 splines, and to those after the 4.90 gears they came in the 00-04 models with fender flares.

[sneakyninja]

Damn i thought i replied to this last night but i must have forgot to hit post

Anyways It might be a regional thing because most of the leaf sprung 4wd sports in these parts have the rear air locker that i have seen so maybe they were sold more like the gen 1's with 4.88's only in certain areas and not a trim level thing like the Gen 2's. The 34 spline thing i saw either on the CAPS program or on ARB's website

[Gravy]

This thing is still sitting in the garage lol

[williambelk587]

Whats the width wms-wms on the factory rear with the air locker?

[JBsTrooper]

Originally Posted by williambelk587

Whats the width wms-wms on the factory rear with the air locker?

yeah, what he said. i'm looking to go to the pull-a-part and pull one of these with all the stuff necessary to run it

[sneakyninja]

pretty sure it's 59" or really close to that.

[Jeff@TheQuadShop]

I'm going to put one under my Mazda if I can ever find one with the 4:27 gears.

[MudRaider]

Originally Posted by Raole Duke

The Sports with a locker are rare, if not entirely out of country. I saw one on monterosportonline a long time ago, I think the guy was from Australia. Here I think all we have is LSD. Never heard of the 34 spline axles, I know the 2.4/3.0 had 28 splines, and to those after the 4.90 gears they came in the 00-04 models with fender flares.

I have one from a 98 in my 87. one of the sweetest mods ever. Stopping 35's with the stock 87 brakes was scary. Now it stops on a dime and gives change with the 98 disc brakes all around.