Converting Clutch-Based LSD to Geared LSD on a Tacoma PreRunner

Hello everyone,
I’ve got a Toyota Tacoma PreRunner 2WD with a clutch-based LSD diff. Over the years, I’ve added a few upgrades like a 3-inch lift and some solid off-road tires with good tread. I mainly use it for camping trips, driving on gravel, and light off-roading on flat, dusty trails. So far, it’s been handling everything without a hitch.
That said, I’ve been thinking about the possibility of tackling slightly more exciting off-road terrain (nothing extreme like rock crawling but perhaps steeper hills, uneven surfaces, or more challenging dirt trails).
From what I’ve learned, a geared LSD does a better job transferring torque and is built to last longer, especially when things get tough on uneven terrain, compared to a clutch-based LSD.

Now, before I go further, I know some might suggest trading it in for a 4WD or selling it and buying a 4WD. While I respect that opinion, I’d like to stick with this truck since I’m the first owner and have already invested a lot in off-road upgrades and accessories, etc.

So, I’m reaching out to ask the forum for advice on this potential conversion.
Specifically:
Cost: What kind of budget should I expect for the swap, including parts and labor?
Performance: I’m doing, like uneven dirt roads, steeper hills, uneven surfaces, or more challenging dirt trails (light to moderate trails, loose dirt, etc.)?
Gas Mileage: Will swapping to a geared LSD mess with my fuel efficiency much?
Future Problems: Are there any known issues with geared LSDs in the long term (maintenance, reliability, etc.)?
Is it worth it?: Or is the clutch-based LSD already sufficient for my use case?

I’d really appreciate hearing from anyone who has done this conversion or has experience with both types of LSD in a similar setup. Your insights will help me decide whether this upgrade is worth pursuing or if I should stick with my current setup. T

Thanks in advance for your advice and suggestions.

Cheers!

 

I wouldn't go from one LSD to another if you are looking for better performance. It would probably be about the same cost to go with an actual locker, like an air locker. You'd have to turn it off and on, but I think it'd be your best bet for increased offroad performance.

 

Maybe take a look at the Eaton Detroit Trutrac.

 

I have a 4x4 TRD Sport 8.4.
It came clutch LSD. Now has TrueTrac.

A clutch LSD wears and was spec'd on the truck for 265 65 17 tires.
Larger tires probably overpower it.

 

The downside to an air locker is that when it’s unlocked, it acts like an open differential, which can let one wheel spin freely while the other doesn’t. That can feel like a step down compared to the LSD, especially when driving on pavement.

 

Nice setup! BTW, is your TRD sport manual or automatic?

 

It's a trade off for sure, but one LSD to another is only going to marginally improve the offroad ability which sounded like the reason for the change. I never even turn the LSD on on my truck unless it's to screw around, I just let the traction control take care of things on the pavement. Does your truck have the LSD on all the time? Mine you have to actually turn it on. Are you sure you aren't confusing the LSD kicking in and the TCS kicking in? One is the clutch in the diff like you said, the other i believe runs off brake modulation at each corner and cutting engine power.

 

This truck came equipped with an LSD that's always on because it doesn’t have an on/off switch. It’s part of the base model. Toyota confirmed that my truck has a geared LSD, but I’m a bit confused about it. Geared LSD seems more relevant to clutch gearing, and my truck has an automatic transmission.

 

Interesting... So 05 to 08 had a mechanical LSD. Never knew that. After that they went to brake contolled auto-LSD. Not sure what kind of mechanical LSD it has, cant find if it's torsen or a clutch type, but the one post I saw mentioning it said it is probably clutch type. Most of what I could find is people arguing over the existence of the mechanical LSD, as most thought it was only ever the brake type auto lsd via traction control (TRAC). Interesting stuff. I can get now why you want to keep the LSD for the street since you must not have traction control like I was assuming.

 

Did I miss somewhere the year of your truck?

I think things changed somewhere during the 2nd gen run

 

Just rebuild your current mechanical LSD. Here's about the only thread on it (with part numbers) I could find:

Replacing clutch plates in rear differential | Tacoma World

 

manual

 

Eaton Truetrac helical Torsen (torque sensing) for the win. I had one on the rear axle in my 2G truck (which my son now has) that I put in when the factory mechanical LSD got tired. The Truetrac is fantastic in the real world. Seamless moving power to the wheel with traction on pavement/dirt/snow/wet.

If you have been getting where you want with a tired factory clutch LSD in a 2WD truck then you already know how to use your truck and will like the upgrade.

Lockers are nice for the 0.1% when you need one (and I have a rear locker in my current SUV). TrueTrac is nice 99% of the time. Mine was ~$1.1K installed pre-Covid.

 

To answer one of your initially posted concerns, I think that a 2WD with something like a Truetrac, is really quite capable if you avoid certain situations. I put a Pwertrax unit in an F150 years back and it made a nice difference.
I think you're on the right track and agree with the recommendation of the truetrac.

 

So it makes sense that the dealership's statement was 100% correct. My truck has an automatic transmission, so it should have a geared LSD.

 

It's technically not a "geared" LSD. It's mechanical but uses a pre-loaded clutch pack that limits slip (like posi-traction). The clutch pack wears out over time and needs to be rebuilt.

 

So, does that mean my truck came with a clutch-based mechanical LSD? My interpretation of your statement about the 'pre-loaded clutch pack that limits slip (like posi-traction)' especially the word 'clutch' is that it typically applies to trucks with manual transmissions. Is that correct?

 

Yes. Irrelevant of the transmission.

Just for fun, manuals have a clutch to engage the engine. Automatics have internal clutch packs to transfer power as well

Don't let the word clutch throw you

 

Early models had a clutch type LSD that can be verified by getting underneath the truck to see if it has a red vertical sticker that says LSD.

later years did not.

the factory LSD is a clutch type. Meaning it is sensitive to fluid choice, can wear out, and can be overpowered by bigger tires.

the truetrac LSD is not a clutch type. Not every LSD is clutch type. For example a helical LSD. That does not require maintenance by not having a clutch that wears. All clutches wear. Transmission clutches. AC compressor clutches. Etc.

 

Truetrac does not fit the early 2nd Gen TRD OR PreRunners.

Ask me how i know....