2005-2008 Mechanical LSD rear Differential facts put to bed, real world!

I posted this on a post on another thread, thought it was important enough to start it's own thread.

OK, let's put this to bed once and for all about the 2005-2008 mechanical LSD!

Jesus, I spend waaaay too much time on my Tacoma, it's 11PM, lol!


Summary, I admit I am half right and half wrong. Going by wheeling experience, I'm right, going by pure technical aspects I am wrong.

I literally just did these experiments...

1. Placed floor Jack on rollers under the rear axle on the right side. Lifted the rear right tire off of the ground. Started the truck, put it in drive. The rear right tire spun freely, no movement from left rear tire, BUT, rear differential was making noises I didn't like. Like clutches trying to grab. I tried reverse. Same thing. I tried applying the brakes, right rear tire stopped. Tried emergency brake, right rear tire (as expected) kept turning. Left rear tire did not move.

2. Placed floor Jack on rollers under the rear axle on the left side. Lifted the left rear tire off of the ground. Put it in drive, the left rear tire free spin, truck did not move. I applied the brakes, truck did not move. I put the truck in park, applied the emergency brake in full, no tires moved. Put the truck in park. Applied emergency brake at half of the way down. Put the truck in drive, with the left rear tire off of the ground, axle resting on the Jack with rollers, the truck started to roll forward, both wheels spin at the same rate, but with the left rear tire in the air.

3. I used the same floor Jack on rollers, jacked up the left rear tire so that it was off of the ground several inches. I placed 2 2"x6"x 10' boards on top of each other, nailed together under the left rear tire. I placed a trash can weighted down with a weekends worth of cut up scrap wood at the end of the boards so they would not move. I Lowered the Jack just enough to where the left rear tire was resting on the 2"x6" boards to have some traction, but still pull the Jack along with it. I placed the truck in drive, at idle speed I let it run down the boards, when it got to the end of the boards the axle rested on the Jack with rollers. Once the left rear wheel was off the boards resting on the Jack on rollers, the truck kept going with the left rear tire free spinning for a couple of rotations, then the truck jerked and surged forward pretty quick and the Jack on rollers stayed in place for maybe another 10' and couldn't keep up and fell out, then left rear tire hit the ground. Scratched up my axle pretty good lol! Thought I broke the Jack, but I think it's fine.

In conclusion these are my findings....

At complete rest, like you parked your truck with your right rear wheel is in the air resting on the axle hanging off your driveway and go to bed, in the morning, your boned! Truck ain't moving!

At complete rest, like you parked your truck with your left rear wheel hanging off your driveway on the axle, then go to bed. In the morning, you will make it to work on time, apply emergency brake half way and although you will probably kill your axle housing dragging it along your concrete driveway until your left rear wheel gets to solid ground.

Now, the interesting part...

This is why I was so dead set in LSD working so well as a 'locker'when you drive correctly.

In test #3, with the truck rolling at idle speed consistently for the length of the boards, as soon as it reached the end of the boards and fell onto the Jack on rollers, the left rear wheel spinned a little faster than the right rear tire which was still moving at idle speed, then the truck kept going with the left rear tire off the ground now spinning at the same rate as the right rear tire.

So what I think is happening in my experience is that I keep the Rpms steady in situations where traction is sketchy, since both wheels are moving (key point, moving) at the same rate when one looses traction, both wheels have enough traction to engage the clutches, 'locking' the rear differential, which as long as I stay steady keeps me having traction on both wheels, then once I accelerate, the differential is still engaged and gives me traction until I let off the gas.

So again my apologies, I have been half right and half wrong, the effectiveness of the 2005-2008 mechanical LSD depends on you situation, like if your dumb enough to park with half your truck hanging off of a cliff, and your driving. Keep it steady, let the differential do it's job, don't park half off a cliff, you will be OK.

Hope this helps clear up this issue.

 

Thanks for this. Was wonder how well the limited slip works in my 06 off-road.

 

If you have the E-Locker. You don’t have LSD.
It’s open until you lock it. That’s why 05-08’ OR trucks suck in 2WD.

09’+ had open diff as well, but they got the Auto-LSD. Which uses the brakes like a LSD.

 

I meant to say how well it works when off-roading. I have a 2wd sport. I've felt the lsd work when off-road just not sure how well it works. Haven't been stuck yet on easy dirt trails looking for remote campsites.

 

1wd more like it amiright

 

Tries to more like, it also cuts engine output power and pulls timing so if you think you can use it to rip fat two timing uncle Burnie's you're sadly mistaken.

All the "Auto LSD" has done for me is screw up power slides, embarrass me at digs, get me stuck and chew up my rear shoes, always one side way more than the other. (Due to torque bias I'm assuming.)

All off road of course.

 

left or right tire wont matter. an LSD in the 05-08 equipped diffs doesnt lock. The LSD only provides clamping clutches that make it so at max (according to spec) there is 150ftlbs of force needed to make a difference of ANY rotation between the tires left or right. Worn out clutches n springs will reduce this figure.

 

Yeah, that’s a fair statement.
1 spins and keeps spinning.

 

TBH, I haven’t experienced the A-LSD in a Tacoma.
I’ve driven a few with it, but never had a situation that it was used.


1. Send it
2. Send it HARDER
3. Repeat step 2 until it won’t send anymore.
4. Send for help

 

Just need to get off my ass and do the locker anytime mod, I have the relay kit with the flyback diode just haven't done it yet.

My 4Runner at the anytime mod that was as easy as grounding one wire that let me spin the both.

Was great for drifty bois.