Possible Replacement Differentials

[dragon]

Hello people,

Questions for the tech gurus on here.
My 2008 double cab long box 4x4 is a sr5 trim with no lsd or locking diff.
Is it a straight swap of the diff if I find an lsd diff off a '05-08 donor tacoma?

[freeze]

that's a good question, since it's mechanical I'd imagine it would work fine, there might be some electronic wiring that may go with the whole project. Etienne (beachboy) did quite a bit of research on this whole thing...

paging Etienne...

[Spooky08]

The oem e-locker won't fit but the mechanical lsd should.

[dragon]

The oem e-locker won't fit but the mechanical lsd should.

that's kinda what I'm thinking.

[canadian bum]

I have a mechanical LSD for sale. I could install it for you as well. PM me if your interested.

[dragon]

what type of lsd is the factory one, '05-'08
is it clutch driven, torsen-type, helical, etc?
I'm assuming a clutch-type.

another newbie question, the lsd will only engage in 2wd right?

btw - I'm looking for an lsd over a locker b/c I'll be spending more time on-road than extreme off-road.

[Spooky08]

the lsd will work in both 4wd and 2wd, it is mechanical so it will do as it like ... so to speak and i believe it is a clutch type.

[canadian bum]

Yeah its clutch type I have mine in a box here waiting for a new home.

[BeachBoy]

my rear has mech LSD and locker, direct swap, just change the 4wd box too.

might have to solder a few more LEDs in your dash as yours doesn't have all of them.,

[Winch]

btw - I'm looking for an lsd over a locker b/c I'll be spending more time on-road than extreme off-road.

OK, I'm not a guru on LSD's but what could possibly be the advantage of wanting an LSD for on-road? I know they are good for burn-outs and getting the back-end to fishtail a bit better, but they sure as heck are a lot scarier in winter on ice due to the advantage (as mentioned above) of both wheels breaking away at once. Are you into stunting, because otherwise I doubt that you'd want to spend the money on an LSD. A selectable or open diff is way better for Canadian conditions (ice). Just my 2c.

[dragon]

now I'm not a guru on lsd's either but my limited use with and limited research on them is they will help with traction when used properly.
yes most people associate lsd's helping with the launch on the drag strip & laying down a posi.
They also do help entering & exiting corners at higher speeds.
I currently have a quaife lsd on my summer car, an acura rsx.

For the taco, I'm assuming it will help with low speed traction is certain situations. I've heard stories of vehicles with lsd sliding out of control, but I think that isn't the lsd's fault. Enter an icy corner at high speed and the vehicle will slide, lsd or not.

Some people think that lsd's & 4wd make them invincible. It's amazing how many trucks & suv's with 4wd & ESC & other electronics still end up in the ditch. I think the biggest factor is driver input.

[Dante's Taco]

Hey, for a newb like me, that's good to know (about the LSD being possibly a disadvantage in our climate); I had always assumed my SR5 with open diff was the most useless option.

Damn if you don't learn something new every day.... :D

[Winch]

Yep, I agree - driver input. An LSD in a truck with RWD/4WD would be quite different than an LSD in a FWD like the Acura, though. I think the main concern with an LSD or worse yet, automatic locker, is going straight up hills at speed when there are icy spots. While with an open diff, chances are only one wheel will break away and start spinning while the other maintains linear direction, this same advantage is not there with LSD's and to a greater extend a locker as both wheels will tend to break away simultaneously, which is worse in a truck, sending the vehickle in a tailspin. Not nice, unless you plan it.

[canadian bum]

The Factory LSD is not that aggresive so it doesn't break loose that bad in winter. I find that it helps move better since both rear tires are trying to move the vehicle. So in winter I was hardly ever in 4x4 unless I wanted the ABS disabled because it sucks. I hate when these new vehicles think they can drive better than I can. Electronics make an average driver good but hinders an excellent driver.

[Doc McCoy]

The Factory LSD is not that aggresive so it doesn't break loose that bad in winter. I find that it helps move better since both rear tires are trying to move the vehicle. So in winter I was hardly ever in 4x4 unless I wanted the ABS disabled because it sucks. I hate when these new vehicles think they can drive better than I can. Electronics make an average driver good but hinders an excellent driver.

Man is it hard to be humble ... when you're perfect in every way ;)

[freeze]

I guess it has something to do with the way....That I fill out my skin-tight blue jeans haha.... love that song!

My BMW has a Qauife LSD in the rear set for medium lock up. I was driving a highway in the winter, pretty safe and started to hit a hill 5th gear real easy. The pavement looked dry not a spec of dark (black ice). There was grey ice that looked like the pavement half way up this small hill at highway speed and that LSD locked up and put me into a 360 facing the wrong way on the on coming traffic side of the two lane highway. Once that LSD locks, the rear end will follow the taper of the road real quick, counter steer really doesn't help at that point.

LSD is great for spirited dry pavement driving or drifting :D

The main reason for going with a TRD Off-Road was for the selectable locker and not the LSD in the sport. I would love to have the quad cab short bed but having an open diff in the winter is super important, specially with the conditions that I end up having to drive.

Also a big reason why I didn't go with the Aussie locker when it first came out. Saved up for the ARB because the 81 was a ski truck too back in the day.

[uriedog]

Know whats in your truck? I am sure there are lots of people here that have no idea.

http://home.4x4wire.com/erik/diffs/

[jreid]

This thread is really interesting stuff! I had no idea that an LSD could be a disadvantage in the winter.

[Winch]

Yep, I agree Nathan. I believe that the reasons so many trucks and SUV's end up in ditches all the time are:
1. They have LSD's or automatic lockers
2. Many people driving these vehichles don't have a clue what they're doing
3. They are rear wheel drive. And for some reason or another, people don't use 4WD, which makes me wonder why they bought a 4x4 in the first place since they don't off-road them anyways. A buddy of mine bought a used landrover awhile ago, and the 4x4 shifter was rusted shut to the T-case cover (probably never ever had it in 4WD)

So, to me the benefit of slightly better traction does not outweigh the risks of icy highway driving (unless you like risks of course) :D

[dragon]

I have heard (& been in cars with) these things happening, again with other vehicles, mostly rear-wheel drive cars & 4x4's not having the 4wd engaged.


So this begs the question: any sport tacos with the oem lsd end up in the ditch or spinning out that you can attribute to the lsd?

[Tacorossa]

I spent 3 winters with my LSD and all season on/off road tires. I have to say that I've never personally experienced anything to the extreme as those have mentioned above. Sure, there is some driver finesse involved, but you have to practice breaking the back end loose and learn how your truck responds. I find the response to be very predictable with the LSD and some extra weight in the back.

I got used to an LSD with my Mazda truck. It is 2WD (partly) and came with an open diff. I found I could get stuck on a booger with a 1WD truck. I put the LSD on and haven't looked back.

I now have studded winter tires on my tacoma, so it tracks straight even when the LSD engages. I always use 4WD in the city though. Highway, 2WD with extra weight in the back. No issues or concerns to date.

[BeachBoy]

Get my '08 off-road rear axle, it's open and has locker when you need to get out of the snow bank;)

[Doc McCoy]

Yep, I agree Nathan. I believe that the reasons so many trucks and SUV's end up in ditches all the time are:
1. They have LSD's or automatic lockers
2. Many people driving these vehichles don't have a clue what they're doing
3. They are rear wheel drive. And for some reason or another, people don't use 4WD, which makes me wonder why they bought a 4x4 in the first place since they don't off-road them anyways. A buddy of mine bought a used landrover awhile ago, and the 4x4 shifter was rusted shut to the T-case cover (probably never ever had it in 4WD)

So, to me the benefit of slightly better traction does not outweigh the risks of icy highway driving (unless you like risks of course) :D

Personally, I normally only use 4x4 in winter for launching. Anything at speed I prefer 2wd/rwd. My reasoning is that I want to know what I'm driving on. I can feel the road getting slippery that much faster in 2wd.

I remember heading out to Cochrane (early spring) and I had stopped in Crowfoot. I was getting back on Crowchild trail and the on ramp was rather icy. I look in my rear view mirror and see some :):):):):):) bag in an AWD Subaru Impreza (nothing against 'ru's. My other ride is a legacy). He keeps trying to push me faster. I probably could have got going a little faster by throwing it in 4 but wanted to keep track of my traction. Around the bend, I was ice drifting right on to Crowchild. :):):):):):)bag is still right on my tail, pushing me. Within one block the bag o' :):):):):):) had flipped around and went into the ditch backwards. Got to see the whole thing in my rear view mirror. A perfect example of over confidence due to AWD.

As for purposely not using 4 when it is needed ... I don't get why people do that.

[dragon]

I guess the debate will always continue as to which is preferred; an lsd or a locking rear diff.
I used to believe an lsd was better for on-road and a locker was better for off-road.
Every time I read another thread or reply, I flip back & forth.
I don't know what to do.

[City_Rider]

I guess the debate will always continue as to which is preferred; an lsd or a locking rear diff.
I used to believe an lsd was better for on-road and a locker was better for off-road.
Every time I read another thread or reply, I flip back & forth.
I don't know what to do.

Ya, I hear ya - I haven't had any issues with my LSD doing weird s*** (strictly mechanical) and I have only REALLY had it engage at low speed and no traction for one wheel (sitting cross threaded in ditch with one tire on ground the other in the valley).

I'll stick with my LSD...

[freeze]

Even if you're in 4WD or 2WD, you should be able to feel everything through the steering wheel. If I see the highway look matte and tacky it's going in 4WD ASAP (I'm not into that extreme stuff), it's not worth taking the chance of losing the rear end or getting understeer (push) without being able to tap the gas and let off to get direction.

That's what I love about the 4WD is the ability to steer with the brakes and gas on ice, you'll get understeer at first but once all the weight shifts to the front you get great directional control even on sheer roads then you can keep balancing between gas and no gas/light brake to steer.

In 2WD on ice, it's really hard to be able to do that at speed, it's fine for in the city but as soon as you're getting up to speed it doesn't work as well.

Even in 4WD you'll feel everything in the front end and through the steering wheel. As soon as that front end get's a little "light" or loose, it's time really be alert.

The rule of thumb is:
- LSD great for spirited driving in corners/not great for slick roads/ok for max traction with the aid of the ebrake
- Selectable locker great for max traction/great for slick roads/not great for driving corners
- Open diff great for driving in the city and straight highway/good for slick roads/not good for max traction/not good for corners

Eventually you'll be wanting a selectable locker... it's a natural progression. Instead of spending money on a LSD then wanting a selectable locker after, you might want to consider just jumping to a selectable locker.

LSD is great if you're hammering the dry roads and nice curves of the 1A or in BC. Once you're off the pavement it's natural to want a selectable locker after a while. thoughts?

[Doc McCoy]

...
The rule of thumb is:
- LSD great for spirited driving in corners/not great for slick roads/ok for max traction with the aid of the ebrake
- Selectable locker great for max traction/great for slick roads/not great for driving corners
- Open diff great for driving in the city and straight highway/good for slick roads/not good for max traction/not good for corners

Eventually you'll be wanting a selectable locker... it's a natural progression. Instead of spending money on a LSD then wanting a selectable locker after, you might want to consider just jumping to a selectable locker.

LSD is great if you're hammering the dry roads and nice curves of the 1A or in BC. Once you're off the pavement it's natural to want a selectable locker after a while. thoughts?

I completely agree! With this part. ;)

[Doc McCoy]

Even if you're in 4WD or 2WD, you should be able to feel everything through the steering wheel. If I see the highway look matte and tacky it's going in 4WD ASAP (I'm not into that extreme stuff), it's not worth taking the chance of losing the rear end or getting understeer (push) without being able to tap the gas and let off to get direction.

That's what I love about the 4WD is the ability to steer with the brakes and gas on ice, you'll get understeer at first but once all the weight shifts to the front you get great directional control even on sheer roads then you can keep balancing between gas and no gas/light brake to steer.

In 2WD on ice, it's really hard to be able to do that at speed, it's fine for in the city but as soon as you're getting up to speed it doesn't work as well.

Even in 4WD you'll feel everything in the front end and through the steering wheel. As soon as that front end get's a little "light" or loose, it's time really be alert.
...

That's kind of my deal Nathan ... I'm not at speed if I need 4wd. It's kinda of like a memo from the road to me saying;

Are you sure you need to get where you're going 3 to 5 minutes faster? I think you should take it easier.
-thanks in advance
The Road
Could I go faster in 4wd? Sure! I know for my self that I am not fast enough to make the corrections at that point (and have no interest in practicing). Speed Racer freeze, with your race background, is probably a different story.

I know you can feel the road through the steering wheel in both situations. In rwd, I find I know right away. As in, as soon as my front tires enter a slipperier spot than my rear tires. That microscopic fishtail on the highway straightaway lets you know you're driving like a dumbass. If I need 4wd in a situation ... it's there. Once again, and this is just me, I am not at speed when this happens. At least, I have not been. *knocks on wood*

Plus, oversteer rules! Who doesn't love letting the back end out a little?!? To regain control, simply let the gas pedal out slightly and point the wheels where you wanna go.

Let me say this ... without a doubt, 4wd is the safer way to drive in winter conditions from a strictly mechanical standpoint. At the same speed as rwd. Start increasing the speed over what speed is safe for a Rwd and that advantage disappears. Personally, I think it gives a lot of drivers too much confidence. If you feel the road is a little looser with the steering wheel but you have uninterrupted forward momentum, you may not realize that hitting a large bend in the road at speed is not such a good idea. Rwd is my constant wake up call.

[canadian bum]

Good debate. Like said above the Taco LSD is not extremely aggressive but enough to keep you going on the roads. I'm probably going to miss it this winter. Even with my selectable locker. When its locked its way to aggressive and when its unlocked well its just a one tire fire. I'll probably be in 4x4 more this winter than 2wd. I have the same mentality of driving as Doc. I can feel the road much faster and it keeps your mind in the game.

4x4 doesn't improve your braking (it does in the second gen trucks because the ABS sucks) since all vehicles already have 4 wheel brakes. So that is why there is over confidence with 4x4 I can go faster so obiviously I can stop faster. Whoops ditch.

Haha Dave I'm not perfect look at all the fancy dents in my truck. None of them are from accidents though.

[freeze]

4x4 doesn't improve your braking (it does in the second gen trucks because the ABS sucks) since all vehicles already have 4 wheel brakes.

If there's drums out back, 4x4 will give you more solid braking as the driveline helps provide the same braking force in the rear as the front. Drums don't provide the most consistent and even braking. If there's discs all around, it doesn't really matter, but with drums it makes a difference. The EBD helps in the new Tacoma/FJ/Runner, however, there is better brake feel in the slick when 4WD is engaged.

The 81 makes a huge difference because all it has is a mechanical proportioning valve for the rear drums.

[freeze]

..... and I'm off topic....sorry guys

[Winch]

Personally, I normally only use 4x4 in winter for launching. Anything at speed I prefer 2wd/rwd.

Yep, but you have an open/ selectable diff, Doc. My point being that an LSD will break away easier than an open diff, and I don't think anybody disputes that due to the fact that both wheels would spin and therefore loose traction rather than just one. In fact many people would purposeffully install an LSD so that they can have both tires break away simultaneously.

There's also a difference between when the conditions are totally predictable, i.e. it's the middle of summer and the roads are dry, or it's in the middle of winter and the roads are covered in snow. And when the conditions are unpredictable, i.e. when you drive 110 km and the roads seem dry, but suddenly going up a hill you hit a shaddow on the south side of the road where the ice hasn't melted and you go into a tailspin. Chances of this happening, depending on other factors of course (tires, driver's input, skill, weight), are greater with an LSD and even greater with a locker that's on.

Driving in 4WD greatly improves braking ability. Most vehichles are pre-set at the factory for maximum braking ability on dry pavement. This usually works out to about 60% braking in the front and 40% braking in the back (through proportioning valves, etc). It is due to the fact that under heavy braking the front end dives, distributing about 60% of the weight to the front. Unfortunately this advantage does not apply on an icy road, since there will be no nose-diving, the front end simply locks up (or with ABS it wants to lock up) greatly diminishing braking ability. Having the truck in 4WD counteracts this, since it is physically impossible for the front wheels to turn at a different speed than the rear (exept AWD vehichles). The rear wheels basically forces the front wheels to keep turning while the front wheels force the rear wheels to slow down.

So, back to the topic. :) LSD is good, but just beware that it may not be as safe at higher speeds on ice compared to an open diff, depending on factors such as mentioned before, so the decision really boils down to whether it's worth doing the swap for the litttle added traction a non-aggresive LSD would provide a 4x4. (The difference is more noticeable in a car, I think)

[Doc McCoy]

Yep, but you have an open/ selectable diff, Doc. My point being that an LSD will break away easier than an open diff, and I don't think anybody disputes that due to the fact that both wheels would spin and therefore loose traction rather than just one. In fact many people would purposeffully install an LSD so that they can have both tires break away simultaneously.

I completely agree.



Driving in 4WD greatly improves braking ability. Most vehichles are pre-set at the factory for maximum braking ability on dry pavement. This usually works out to about 60% braking in the front and 40% braking in the back (through proportioning valves, etc). It is due to the fact that under heavy braking the front end dives, distributing about 60% of the weight to the front. Unfortunately this advantage does not apply on an icy road, since there will be no nose-diving, the front end simply locks up (or with ABS it wants to lock up) greatly diminishing braking ability. Having the truck in 4WD counteracts this, since it is physically impossible for the front wheels to turn at a different speed than the rear (exept AWD vehichles). The rear wheels basically forces the front wheels to keep turning while the front wheels force the rear wheels to slow down.


[begin new thread jack]
Here ... I don't completely agree. I almost do ... so close it hurts but I need to thread jack again. Mechanically I agree totally. It is in application that I find a small fault. If you're locking up your brakes ... you're doing it wrong. Awd or Rwd. You should always have your tires rotating a little unless you are at a dead stop. Always maintains a level of vehicle control. ABS is great and all but everyone should learn the art of threshold braking. There would be a lot less accidents. [/end new thread jack]

[Doc McCoy]

...

There's also a difference between when the conditions are totally predictable, i.e. it's the middle of summer and the roads are dry, or it's in the middle of winter and the roads are covered in snow. And when the conditions are unpredictable, i.e. when you drive 110 km and the roads seem dry, but suddenly going up a hill you hit a shaddow on the south side of the road where the ice hasn't melted and you go into a tailspin. Chances of this happening, depending on other factors of course (tires, driver's input, skill, weight), are greater with an LSD and even greater with a locker that's on.

...

So, back to the topic. :) LSD is good, but just beware that it may not be as safe at higher speeds on ice compared to an open diff, depending on factors such as mentioned before, so the decision really boils down to whether it's worth doing the swap for the litttle added traction a non-aggresive LSD would provide a 4x4. (The difference is more noticeable in a car, I think)

And back on topic. ;)

I think that you have made the two best points here. You may know your LSD and when it should engage, you may know how your vehicle responds when it does ... but if it engages unexpectedly in a scenario similar to the one Gary describes above ... you better know how to respond.

And this last point you make sums up the whole deal. Unless you are building your truck up to race on a track or love bombing around in the summer on a winding highway - (can you imagine hwy 22 with no traffic west of Nanton and Claresholm?) ... LSD is not enough bang for your buck as an upgrade.

[Winch]

If you're locking up your brakes ... you're doing it wrong. Awd or Rwd. You should always have your tires rotating a little unless you are at a dead stop. Always maintains a level of vehicle control. ABS is great and all but everyone should learn the art of threshold braking. There would be a lot less accidents.

OK, hijack one more time: I totally agree that it is critical to master this concept, but point in case, you can improve/ enhance that threshold by approx. 20% before the tires will want to lock up in 4WD. 20% better braking before my wheels start wanting to lock up is a huge difference to me. There is no possibility that one good driver who mastered this art will outbrake another master if he has his truck in 2WD and the other guy has his in 4WD regardless of ABS, etc. (same trucks and tires of course). No way - not even close - I'll put money on it - 4WD will outbrake 2WD by approx 20%. :D

[Doc McCoy]

I think we're mostly arguing different sides of the same point.

- 4wd provides more traction moving forward
- 4wd provides slightly better braking (lets say about 20% which is more than slightly)

I will admit these freely.

I'll have to research a little further on this one but I think I know the answer to the following question;

If a vehicle (in Rwd) is traveling at 100km/h and threshold brakes to a complete stop and the same vehicle travels to 120km/h (in 4wd) and threshold brakes to a complete stop, do they stop within the same distance?

Is a 20% increase in speed equal to the 20% increase in brake performance?

Regardless, we've decided that the aftermarket LSD upgrade has already killed the driver. ;)

[freeze]

I think we should do a "scientific" test :D

[jreid]

How does 4wd provide better braking??? I'm lost on that one I'm afraid.

[freeze]

mostly when it's slick out.

Your disk brakes in the front provide solid and even braking. The rear drums are a little less predictable.

When 4WD is engaged the driveline locks the front wheels and rear wheels together to rotate at the same speed no matter what.

When the front brakes grip it forces the rear wheels to brake at the same force as the front just by association through the driveline. It's as though you don't even need rear brakes when in 4WD because through the driveline, the front brakes will stop the rear wheels.

Think in the way of having only one big disk brake on the driveline and no brakes at all at the wheels. If the driveline is completely locked up (4WD) then all four wheels will slow down/stop when that one single brake on the driveline brakes/locks.

[Skibby]

This is a great thread you guys. Very informative. I would love to add my 2cents but i don't know sh*t about this stuff.

[Winch]

I think we should do a "scientific" test :D

Ha ha, yep that's easy. Just find an icy spot somewhere. We should add this to the 202 course, because this same principal actually comes into play while off-roading as well on slippery surfaces :D

[jreid]

mostly when it's slick out.

Your disk brakes in the front provide solid and even braking. The rear drums are a little less predictable.

When 4WD is engaged the driveline locks the front wheels and rear wheels together to rotate at the same speed no matter what.

When the front brakes grip it forces the rear wheels to brake at the same force as the front just by association through the driveline. It's as though you don't even need rear brakes when in 4WD because through the driveline, the front brakes will stop the rear wheels.

Think in the way of having only one big disk brake on the driveline and no brakes at all at the wheels. If the driveline is completely locked up (4WD) then all four wheels will slow down/stop when that one single brake on the driveline brakes/locks.

ah that makes great sense to me. Thanks for the explanation nathan.

[freeze]

It's kinda of a weird idea but it really works!