2004 LC100 - open diffs, LSDs, A-TRAC - newbie questions

[occamsrazor]

Hi,

So I've recently acquired my first 4wd - a 2004 LC100 4.7l VX Ltd, chassis UZJ100, it's a Japanese Domestic Market (JDM) import.

I've been reading a whole load of threads on this board trying to understand the concept of differentials, A-TRAC, VSC, etc.

Am I correct in saying that in this vehicle all the differentials in the front, center and rear are of an "open" type and it uses A-TRAC (i.e. brake application) to adjust power between the wheels during wheel slippage situations? This application of the brakes is supposed to create an effect similar to a limited-slip differential - but the vehicle does not use LSDs. Is all that correct?

The reason I ask is the only manual I have is in Japanese, which I can't read, but I can make out parts that refer to VSC, "TRC" (which I presume is A-TRAC) and also there is a page "LSD". I read that the very early LC100s had LSDs, but did any later models have them? I'm just curious as to what exactly I have really. Is there any way to tell from inspecting the vehicle?

My other question is regarding the centre-diff-lock button. If A-TRAC can regulate the power as described, what is the need for a CDL, and in what situations would you just use the A-TRAC, and in what situations would you engage the CDL? In what situations would you definitely NOT engage the CDL?

Thanks for your help, am just trying to get my head around all this.

Ben

 

[jdlsantos]

Hi Ben, congratulation about your new rig, you will not regret on have a LC.
I am not expert on LC100, also i am new owner of one too, but I come from a LC80 and I was read a lot about it here.
check this link to FAQ,
https://forum.ih8mud.com/100-series-cruisers/30754-100-series-lc-lx-faq-featured-trucks.html

"I've been reading a whole load of threads on this board trying to understand the concept of differentials, A-TRAC, VSC, etc."
A-TRAC is used off road
VSC is used on road

"Am I correct in saying that in this vehicle all the differentials in the front, center and rear are of an "open" type and it uses A-TRAC"
Yes you right!

"This application of the brakes is supposed to create an effect similar to a limited-slip differential - but the vehicle does not use LSDs. Is all that correct?"
is more effective than LSD effect, but less than a real locker.

"I'm just curious as to what exactly I have really. Is there any way to tell from inspecting the vehicle?"
Check beside the oil filler plug at the rear differential, should be a sticker that say "just LSD fluid", if not check on www.toyodiy.com is a web site for parts number, but could give an idea when to put your serial vin.

For sure all your questions are answered better through this forum, but you will need to spend some time reading.
good luck

 

[occamsrazor]

Check beside the oil filler plug at the rear differential, should be a sticker that say "just LSD fluid", if not check on www.toyodiy.com is a web site for parts number, but could give an idea when to put your serial vin.

So I got underneath the vehicle today and on the rear diff I see a white sticker saying "Only LSD oil". Presumably this means I have a rear LSD. So what does that mean regarding A-TRAC? As a 2004 model I presumed it would have it - is it possible I have both LSDs and A-TRAC? Now I've verified that I have LSDs (well, at the rear at least), is there a way I can I check if I have A-TRAC or not?

Thanks,
Ben