Front/rear locking differentials

[Megaton]

I know it's probably been hashed and rehashed here,but I don't have time to use the search.I'd like to have the info all in one place.I have a 97 LE with AT,gear shift 4x4,and LSD.I'd like opinions on what is out there other than ARB air lockers(at least affordable ones).Lokka looks good,but only the front is available.My car is a daily driver but I would like it to be more capable off road.I'm going to use 31x10.50 tires so stock gears should be Ok.Thanks,Tim.

[jyeager]

There is nothing but the ARB for the rear, and I'm not sure you can use it in your LSD carrier. You might have to get an open diff carrier to install the ARB in to for your car.

But what most people do is they tweak their LSD to a higher breakaway torque in the 200-300 range giving great rear traction. And most people use the Lokka for the front. Then you're pretty much golden.

 

[greenda3]

If your poor like me eeld up the front and install locking hubs. Have true 4x4 or only lock one hub for snow/hardpack driving so the tires dont scrub to bad.

 

Sent from my LGMS395 using Tapatalk

[hawairish]

There is nothing but the ARB for the rear, and I'm not sure you can use it in your LSD carrier. You might have to get an open diff carrier to install the ARB in to for your car.

But what most people do is they tweak their LSD to a higher breakaway torque in the 200-300 range giving great rear traction. And most people use the Lokka for the front. Then you're pretty much golden.

 

 

TJM has a rear air locker that's spec'd for a Patrol...which is a 33-spline H233B.

 

The TJM (168PL04) and ARB (RD135) units replace the entire carrier, so they're carrier agnostic. You just swap the ring gear onto it, press on bearings, install in diff housing, and set lash. (Well, and also plumb air lines, install compressor, etc.)

 

The LSD can be tweaked. I just swapped from open to LSD with a re-packed LSD. Hit >300 ft-lbs at some point, but re-arranged for 175 ft-lbs. Requires thicker discs/plates, but swapping plates with discs also helps.

 

Steven at Rugged Rocks has also been trying to bring a rear mechanical locker to the scene for some while now. If it comes alive, it will likely require an open 2-pinion carrier.

 

Lokka or ARB (RD202) for up front. Lokka installs in the open carrier, ARB replaces the carrier. ARB will likely require different shims. There's a Lokka group buy going on now for about $300 shipped...direct from Lokka, it's about $400.

 

Also, your stock gears will have to suffice...I don't think you have an option. Unless the R&P that exist are spec'd specifically for an R50, they won't work...wrong cut. But you'll be fine at 31's.

Edited August 13, 2015 by hawairish

[Megaton]

Great info guys! Many thanks.So I guess if I get a LSD repack kit I can use my differential and tweak it to a higher breakaway?

[hawairish]

While there's no kit per se, you can buy thicker discs/plates from any Nissan dealership. Though, when I bought some the other month, national supply was getting low..5-7 weeks to get some from Japan, if available.

 

However, the setup in the Pathfinder only uses 40% of the potential friction surfaces because it stacks plates together. If you replace every other plate with a disc, you instantly add friction. Make some pieces thicker, more friction.

 

My adventure here: http://www.nissanpathfinders.net/forum/topic/40280-was-the-factory-lsds-breakaway-torque-any-good

[Megaton]

Hawairish,I checked out your "differential adventure" and your efforts are appreciated more than you know.Transmissions and diffs are black magic to me.I'm a mechanical cave man (some say I'm a cave man period).I have to have the work done by a mechanic so I have to be specific with what I tell him to do.If I have the differential disassembled and replaced a plate with a disc on both sides,would this work? I'm looking for the same results that you have.Not to tight to bind the drive train but tight enough for better offroading.Please forgive my ignorance of this subject.You are a godsend. Thanks.

[hawairish]

Haha, too kind! And sorry about the delayed response...just completed a marathon 3-day truck overhaul for another R50 owner. Madness!

 

Ok, here goes (long post, heads-up)...

 

Everything worth knowing (specs, instructions, and parts info) is found in Propeller Shaft and Differential Carrier ("PD") section of the FSM. The most notable things are the specs and parts explosion. Best bet is to print the entire section for your mechanic.

 

The specs are found in the Service Data and Specifications (SDS) section towards the end of the H233B subsection. It looks like this (for a 2004 Pathfinder):

 

 

Somewhere before this in the PD chapter, you'll find either a full parts explosion for all the parts, or a smaller explosion like this (again for a 2004 Pathfinder):

 

 

BTW, for a 1997 Pathfinder, the LSD is listed as having 5 friction discs, 6 friction plates, 2 spring plates, and no spacer (per side). It specs at 65-80 ft-lbs.

 

Breaking down the parts:

1. Friction plate: stays stationary to the carrier

2. Friction disc: stays stationary to side gears

3. Spacer: some have a spacer that is equal in thickness to 4 plates/discs. It's just a big 6mm thick ring.

4. Spring: not shown in picture is a ring with a concavity. There are two of them per side (some older models only had one per); when the carrier is assembled, the spring plates will flatten and produce pressure.

 

The friction plates sandwich the discs, and when the torque differs between wheels, the discs twist between the plates to create friction.

 

Before ordering any parts, you should know the assembly order and thickness of each part...this requires disassembly. Note the list of part numbers above. Your LSD will consist of some combination of those parts. Most, if not all (except the spacer) will be 1.5mm thick. To thicken the stack, you simply replace the 1.4mm pieces (if any) or 1.5mm pieces with something thicker. The FSM specifies how thick that stack can be, so take note of your initial and calculated thickness. I found it easier to just find the nominal thickess (i.e., some will be 1.47mm thick, but treat them as 1.5mm thick) and see what parts can be replaced or rearranged.

 

The "optimal" ratio of discs-to-plates is 5:6...this is the arrangement that uses the max number of friction surfaces. It is not necessary to have that setup, since you can supplement it with thickness in some cases. If you need to bring down torque (in my case, where I was hitting way over 300 ft-lbs at one point), you can keep the same stack thickness and reduce the ratio to 4:7.

 

If you have 2:5, then you have the spacers and need to replace each with 3 discs and 1 plate. If you have 2:9, you need to replace 3 plates with 3 discs per side. Neither of these options are cost-effective, and might not be enough to get the desired numbers. Each disc/plate runs about $30-$35/ea from Nissan...it adds up quickly when you factor things per side. LSDs out of a WD21 will be a much better starting point. LSD parts for all H233B trucks/SUVs pre-2005 are the interchangeable. If using a WD21 diff, put your ring gear and side gears on the carrier, and swap it in. Of course, measure spec and see if it needs rebuilding (the FSM shows how to measure torque...may need to fab your own tool for measuring).

 

Dialing in the right amount of torque took me several tries. It really depends on the starting setup. I had to buy several pieces to hit my numbers, but I also started with a weaker LSD.

 

MY1PATH machined down some extra plates/discs as shims. That is another option if you have the means.

...

 

On a parting side note, the vehicle overhaul done over the weekend included installation of a rebuilt 150 ft-lb LSD into another R50...the owner was very pleased with it. Mine also feels great.

 

Any other questions, feel free to ask!

Edited June 12, 2018 by hawairish

[duke90]

Very happy with the lsd swap and lokka install plus the dozen other things we did to the truck over the weekend! Thanks again Hawairish for all of your time and help with this project.

[Megaton]

Hawairish,you have come through again! Great info. I think I'll go with the Lokka up front and,since the stock breakaway of the WD21 is acceptable to me,change my ring and side gears to a WD21 LSD for the rear. It seems like the most economical and easiest way to go.Again,thank you so much.

[hawairish]

No sweat, man. I think you'll be very pleased with that setup, too.

 

Two more thoughts:

1. You may still want to measure break-away and clutch pieces on the donor WD21...at minimum to inspect for wear. If you can have the downtime, you can use the better pieces from both the donor and current LSDs to freshen up the LSD. Again, just need to know the starting thicknesses of each piece. The FSM also provides measurements/specs for dimensions inside the carrier halves, so using the halves with less inner dimensions would provide more clamping pressure...just don't get the bearing races mixed up.
2. I presume that the 33-spline side gears will fit the 31-spline carrier because they use the same LSD pieces. This is entirely dependent on the lip at the ends of the side gear. You would also need to swap over the spider gears and 4-pinion cross shaft (the side gear cuts are completely different). As an after-thought, you for sure can just move the LSD clutch packs to the 33-spline carrier...they are the same part numbers. Doing it this way, you won't have to remove any ring gears, side gears, spider gears, etc...just undo the 8 smaller bolts that clamp the two carrier halves together.

(Sorry for the mixed info...I realize now how exhausted I was when typing that all up...I had just completed a 40+ hour marathon of R50 overhaul over 2.5 days...brutal!)

 

[hawairish]

LOL...looks like I'm buying another set of diffs from a 95 WD21 this weekend. In case having two sets in my garage already wasn't enough...

 

It's got the LSD, so I will see what the starting number is and try to get it up into the mid 200's per the FSM. The front diff is part of another project I can't stop thinking about right now...I have no use for the diff on my truck, but I think I can design a cradle for making any non-R50 R200A fit our truck (i.e., OE 4.9 gears!)

[Megaton]

No need to apologize.I guess we've all been punch from overwork at one time or another. If you ever want to get rid of a WD21 clutch pack let me know. I have been looking around here and they seem to be scarce at the moment. BTW, Duke 90's ride looks great. Great job guys!

[jyeager]

 

It's got the LSD, so I will see what the starting number is and try to get it up into the mid 200's per the FSM. The front diff is part of another project I can't stop thinking about right now...I have no use for the diff on my truck, but I think I can design a cradle for making any non-R50 R200A fit our truck (i.e., OE 4.9 gears!)

 

That would be amazing!

[hawairish]

So I picked up the diffs and started taking measurements. I also started a write-up about the differences and got plenty of pics. I haven't cracked it open yet. Will probably do that tonight. Stay tuned.

 

At a high level, this is very doable. It would be bolt-on and re-use CVs. The axle would need a mount cut off, a new diff cover (one from a C200 or car-based R200 oughta fit) and CV spacers/adapters (axle is narrower and WD21 has different CV bolt patterns). I have some other ideas, too like using longer CVs from an X/Fr for increased range, and an integrated missing link.

 

It's no SAS, but it'll open up gearing options for sure.