Selectable diff locker debate (aftermarket).

[roflbox]

did some digging around looking for TJM owners, or potential ones:

Aftermarket Diff Locks for a FJ80 (1991)

Hello Everyone! New to this forum and based on Southern Baja. I own a FJ80 1991, and I was wondering if I can install aftermarket locking differential for both rear and front diffs. If that´s possible ... Which would you recommend? Thank you in advance.

forum.ih8mud.com

@Rusty Marlin did you ever get TJMs installed? if so, do you have anything to share?

found another TJM install thread:

AWD to Part time 4x4 with TJM Diff Lock's.

Hi all Its been a while so thought I would post up the current shenanigan's that are going on with my old girl. (the 80... not the wife) What started out to be a leaking pinion seal on the front diff has turned out to be an accumulation of a number of "to do" projects in one hit. With mine...

forum.ih8mud.com

@Ribz0 anything to report on having had your TJM lockers installed for a year?

 

[Bludozer]

Timely for me as my 80 will be headed in soon for gears/rear selectable locker.

I went with a Harrop rear. My feeling on the disengage/reneengage debate concerning harrops is that it’s one of those things that won’t really matter in practice. Especially for people like myself not hardcore wheeling, the locker is mostly an insurance policy. I’d much rather deal with that than all the BS that comes along with ARBs - air lines, gasket issues, compressors etc. both are a compromise but for me it was an easy choice.

 

[Haggis]

^^^That pretty much sums up how I feel about my factory rear E-locker in my 2000 Tacoma. I often refer to it as my secret weapon/insurance policy. I'm really glad I went with the option back then. Wish my 80 had the factory lockers and it would have if I had been the original owner.

 

[aztoyman]

You said you had 12 years of flawless operation. So the ARB wasn't/isn't a problem and your diff was setup well with quality parts. Hard to justify buying something you are unsure of when the ARB has worked so well for you for so long.

Until a failure analysis is done you really don't know for sure what happened first. Maybe the drive shaft went first? Or was it the birf or gear tooth?

If something has been failing slowly over the years you will see it in the fracture face. A sudden fracture looks a lot different than a fatigue fracture. It's definitely more difficult to sort through when you have a pile of ground up parts but if you have the time to clean and look at the parts it can be done.

What were you doing when it failed? Full turn? On the throttle? Any warning signs like a noise or anything that you noticed?

Regardless if you want to look into the failure mode, you did a good job setting it all up years ago and the ARB has held up. Maybe the money you save can go toward stronger drive shaft, 300M birfs or cryo treated gears? An upgrade on the parts that failed instead of replacing one that didn't.

This is just the "thoughts" of a guy that is only running 35's, Aussie lockers and Dirty 30's. Stepping up to 37's soon so a little concerned about how it all holds up.

 

[Broski]

Way back when,, I thought it cool to wire my ARB’s to the factory dial switch. I’ll be tearing my dash apart for a couple of reasons here soon and changing over to individual switches will be done at that time. We’ll see how front digs go on the factory 8” diff.

Technically still not a front dig as you will still have one rear tire pushing

 

[White Stripe]

I would do harrop maybe if a light wheeler or overlander due to the reverse issue. For serious stuff I would go arb. My arb always works. However I would think carefully about fixing the front axle vs going with a different front axle.

 

[Broski]

. However I would think carefully about fixing the front axle vs going with a different front axle.

It's just a ring and pinyon.
He already has a working ARB and RCVs that a big investment that won't work on other axles.

Maybe a adjustment in driving stile is in order

 

[baldilocks]

Technically still not a front dig as you will still have one rear tire pushing

That is true and, honestly, I’ve never had problems with it wired to a factory switch. It’s just more ideal to run separate switches.

 

[IdahoDoug]

If I were you, I'd be inclined to keep the ARBs. They have a long history, and are durable units. The air supply is something a serious wheeler should have onboard for tire adjustments, etc anyhow, and the 100% lock up provides the control you need when getting in and out of serious obstacles. Cost wise, this makes sense and as others have noted you could use some $ saved to upgrade what broke when you do the autopsy.

I watched the videos of the locker needing to re-lock itself, and unless I'm completely missing something, from an engineering standpoint that's not a good idea. When you're stuck and locked up, almost by definition you'll be using heavy throttle and obviously low range, and frequently changing directions as you explore different movements to get out of whatever predicament you're in. So the thought of that hammer blow to the drive train when I reverse hard, then forward, just seems like a recipe to break something. That's the exact force we are all taught to avoid, similar to a spinning tire coming down on a rock and creating a force spike that breaks something. Hitting the throttle, hearing a tire spin and then that clank of engagement would give me the heebie jeebies.

I prefer the full locking of an OEM, or ARB. Sometimes just that few degrees of slip (like a traction control, or viscous coupling needs) is what prevents you from getting moving. Having all 4 contact patches 100% push in the initial instant is what it takes to get 3 tons of vehicle moving. That right there is where the true value of a full locker lives, and to give that up moves significantly away from fully locked, plus exposes things to a force spike. In fact, I'll elaborate a bit more. When I lock my factory lockers up, I do everything I can to avoid the scenario where I'm stuck already and engaging them - precisely because I know it's brutal to be at heavy wheelspin inducing throttle when it locks. Yet this unit under discussion seems to CREATE that situation every time you reverse - you're doing a cringeworthy full locker engagement at high throttle setting.

 

[Rusty Marlin]

@Rusty Marlin[/USER] did you ever get TJMs installed? if so, do you have anything to share?

@rolfbox No, I went with ARB because the TJM's were 6 months out from when I needed to get them installed.
The ARBs also came as a "package" with the NITRO gears.

I still think the TJMs are a better design, but no first hand experience with them, so that's just opinion looking at how they function.

 

[PNWTreeOctopus]

I’m enjoy this academic debate. I’m currently sitting on a brand new set of ARBs, gears, compressor etc. Im currently just using my rig as a family adventure wagon, but I long to push the rig and see what it can do.

I decided that I wanted a robust onboard air system as well so that was a key pet of the decision.

…Also @baldilocks reccomeded them.

 

[nukegoat]

Keep the ARBs. While it may be easy to think of them as complicated and error prone, if you take one apart you'll realize how dead nuts dumb and simple they are. Yes, either the seal collar or the bonded seal can leak. But there are far fewer moving parts and gizmos that can fail. And even when they leak they usually still work.

My $0.02. I hate my ARBs in a lot of ways but they're sort of a necessary evil

 

[baldilocks]

I’ll definitely keep running the ARB’s. As far as we could tell the unit in question is undamaged and still operates correctly. I’ll know more when I remove the third.

There has been a lot of learning and many great points posted to this thread. If it works then why replace it? And the ARB’s have worked for me.

I will call around to gain some info on the reliably and longevity of the bonded seal that seals the piston inside the carrier. I’m not in a big hurry on this.

 

[mudgudgeon]

I hate my ARBs in a lot of ways but they're sort of a necessary evil

What do you hate about them?

 

[mudgudgeon]

I will call around to gain some info on the reliably and longevity of the bonded seal that seals the piston inside the carrier.

If this is a failure point, might be worth replacing while you're in there?

 

[JoeCova]

It’s interesting that many say the Harrops aren’t for hardcore/serious off-roading.

What are people considering serious off-road? When I think of “serious” offroad or technical driving I think places like Fordyce, Carnage and other trails that really need 37s+ and expects body damage.

 

[baldilocks]

If this is a failure point, might be worth replacing while you're in there?

I’m expecting to find out that mine still have years left in them. I expect this based on what others have written on the World Wide Web over the last 20 years. I have never heard of someone disassembling an ARB to replace that bonded seal. But what do I know, I’m just a farm kid that is good with bailing wire, duct tape, and lots of grease.

 

[nukegoat]

I’m expecting to find out that mine still have years left in them. I expect this based on what others have written on the World Wide Web over the last 20 years. I have never heard of someone disassembling an ARB to replace that bodes seal. But what do I know, I’m just a farm kid that is good with bailing wire, duct tape, and lots of grease.

I've replaced 4. But there was a bad batch of seals from 2016-2020ish that ARB basically acknowledged. The new seals I think are viton and fine.

 

[ChaseTruck]

On the ’93, we needed to replace this:

It had failed at the junction of the copper tube.

By the way, I don’t know whether that is the correct image for the RD142, but it was the equivalent part.

 

[ChaseTruck]

@jonheld - for lowering the air pressure: would you happen to have info or a part number for a 70psi pressure switch?