Any way you can tell if you have LSD? (1 Viewer)

[philip g]

Besides pulling the third member?

I am considering a lokka install but you need a different kit for lsd. I don’t want to pull it apart then have to order the locker and wait.

Maybe if I pull the fill plug I can see enough to tell? That’s the only idea I have

 

[Camotubebender]

Jack it up so both back wheels are off the ground
turn one wheel by hand, if the other wheel goes the same direction you have limited slip if it goes the opposite direction it does not

 

[philip g]

Jack it up so both back wheels are off the ground
turn one wheel by hand, if the other wheel goes the same direction you have limited slip if it goes the opposite direction it does not

Hopefully the lsd still works. If it doesn’t work and I order parts based off that and it actually has lsd I’m back to square one

I guess I could rely on that for a positive test and investigate further if it’s negative

 

[Camotubebender]

There is a info sticker on the door that might tell you if it has LSD or you could call a toyota dealer with the vin#

 

[philip g]

There is a info sticker on the door that might tell you if it has LSD or you could call a toyota dealer with the vin#

It’s a jdm

 

[philip g]

Oddly enough when in neutral if you spin one tire the other doesn’t move. When I’m park they spin opposite. Either open or a lsd that isn’t working or worn out.

 

[Navyator]

It’s a jdm

Look under the hood on the passenger side firewall. There should be a placard there (there is on my 91 JDM). Give me a sec and I'll find the codes from a thread I just read the other day.

Edit: Dang, thought I was in the 80 series section. Maybe it's still the same for you where the placard is. I imagine the codes won't be the same though.

 

[philip g]

Look under the hood on the passenger side firewall. There should be a placard there (there is on my 91 JDM). Give me a sec and I'll find the codes from a thread I just read the other day.

Edit: Dang, thought I was in the 80 series section. Maybe it's still the same for you where the placard is. I imagine the codes won't be the same though.

The placard is there for sure but yeah idk the codes. I’ll see if the aussies do

 

[philip g]

The other interesting thing. With one rotation of the tire the driveshaft spins 2x around. Seems to indicate super high gearing.

I’m on 35” tires and everything seems to be geared right. I’ll have to count teeth when I take it apart I guess

 

[AirheadNut]

Can you post a photo of the data tag on the firewall? IIRC if the axle code ends in a 3 or 5 it is LSD, if 2 it is open, if 4 it is locked. Ring gear size is the letter in the code, ratio is the first two numbers. This generally holds true, though on my LJ78 the axle code is G144. This would indicate an 8" ring gear, 4.875:1 ratio, and 4 pinion locking differential. All this is correct except for the locker, which mine never had.

To get an accurate reading on your gear ratio you will want to rotate the driveshaft and watch the tire spin. Keep track of how many driveshaft rotations are required for one rotation of a tire. If you rotate a tire and the opposite tire rotates in reverse, this will mess up your count.

 

[AirheadNut]

Assuming you have a KZJ9x model, I am pretty sure they came with 4.10:1 diffs for the JDM market.

 

[philip g]

Assuming you have a KZJ9x model, I am pretty sure they came with 4.10:1 diffs for the JDM market.

There is no way it’s stock gearing on 35” tires it would be very noticeable

 

[philip g]

Can you post a photo of the data tag on the firewall? IIRC if the axle code ends in a 3 or 5 it is LSD, if 2 it is open, if 4 it is locked. Ring gear size is the letter in the code, ratio is the first two numbers. This generally holds true, though on my LJ78 the axle code is G144. This would indicate an 8" ring gear, 4.875:1 ratio, and 4 pinion locking differential. All this is correct except for the locker, which mine never had.

To get an accurate reading on your gear ratio you will want to rotate the driveshaft and watch the tire spin. Keep track of how many driveshaft rotations are required for one rotation of a tire. If you rotate a tire and the opposite tire rotates in reverse, this will mess up your count.

A02A looks like

I might have to just suck it up and pull it apart then order the locker and have it down a few weeks. Which sucks but if it’s what I gotta do…

 

[javelinadave]

Good info! Looks like mine is open too.

 

[philip g]

I am completely perplexed by the gearing on this thing. Jacked it up and spun the driveshaft and got 2 and maybe a quarter rotations per tire rotation

There’s no way this can be running 2.xx gearing with 35s on it, I would like it a tiny bit lower geared though.

If someone is bored would they kindly click on the 2nd gear start button and tell me what rpm they run at some random speed like 30kmph

This would seem to indicate it’s a lsd axle from the no rotation of the other tire symptom

Identify your axle gear ratio | A Turn of the Nut

 

[AirheadNut]

I would hazard a guess that you’re missing a factor of 2 in your calculations. Like you say, there’s no way that your rig has 2.25 diffs, but 4.5 (or 4.56, more likely) seems quite reasonable. That would be one step lower gearing than the factory 4.10.

Another option would be to use a gearing calculator to input your rpm at 100 km/h, transmission gear ratio, and tire size, then play around with differential ratios until it outputs a road speed of 100 km/h. This is the calculator I like to use: Gearing Analyzer | RPM and Tire Diameter to speeds with Shift Tracer - https://www.blocklayer.com/rpm-gear

 

[philip g]

I would hazard a guess that you’re missing a factor of 2 in your calculations. Like you say, there’s no way that your rig has 2.25 diffs, but 4.5 (or 4.56, more likely) seems quite reasonable. That would be one step lower gearing than the factory 4.10.

Another option would be to use a gearing calculator to input your rpm at 100 km/h, transmission gear ratio, and tire size, then play around with differential ratios until it outputs a road speed of 100 km/h. This is the calculator I like to use: Gearing Analyzer | RPM and Tire Diameter to speeds with Shift Tracer - https://www.blocklayer.com/rpm-gear

If that’s the case and it’s running 4.56 I’d probably be as close as I can get to stock gearing as I come up with a 4.69 to be same as stick with 35”s. Wonder if 4.88 are too low. Guess I could go 4.88 and upsize to 37” if it was