Understanding the Toyota E15x series gearboxes, a basic guide to...

i agree with redrkt on this one, when nothing is slipping it's 50/50 based on the video. the power is equally split coming out of the centre differential. but when let's say any one wheel slips, let's say the front left like in the video, then the open centre diff diverts to the front, then the front diff diverts to the left. if it was the rear left slipping, then it would be spinning that rear left wheel only while the other three wheels are not moving. if that was the case, you would lock the centre diff and you'd have both front wheels + rear left wheel spinning now.

think of a fwd car, normally, the power is split 50/50 between left and right, but when you slip one wheel, the side that is slipping is the one that spins while the other is steady. LSD would fix that and turn both at the same time.

if you think of the fwd diff as similar to the centre diff, the lock is similar to a fwd LSD in the way it locks both front/back.

the lock doesn't "activate" the rear, but simply locks the front and back together in case either one slips. by your logic, if it was the rear slipping instead of the front, the car would be rwd and the lock would "activate" the front..

 

I don't know about entrax, but I understand plenty. What you are describing is a plain VC diff, not a VC diff lock. And not only that, it appears you think that the power is being delivered to the open front diff first.

In my explanation of what is happening torque-wise a few posts ago I noted that there was a 50/50 split until wheel slip occurred. This is maintained by the center diff, which is where torque is transmitted to FIRST. The center diff is driven directly by the output shaft thus splitting the output force between the front and rear diffs. As entrax correctly pointed out, the VC diff lock acts like an LSD. So with a 50/50 power distribution when wheel slip occurs it "locks" and apportions more torque where it is needed. The VC diff lock isn't trying transmit any of the torgue during normal straight-line driving because it doesn't have to. The center diff is transmitting the torque 50% front and back. When wheel slip occurs is when the VC diff "locks" to maintain the 50/50 (or close to) power distribution.

I know it is confusing, but if you look at the diagrams and read the Toyota literature it is plainly outlined. Look here for the "description page" http://bgbonline.celicatech.com/90alltrac/MT/MT.htm

Also, there are traction tests involving the Alltrac/GT-Four online. I have a friend with an ST185 that just performed one demonstrating what the 4WD system is doing. As soon as he sends me the link for youtube, I'll post it.

 

The Toyota Repair manual begs to differ for both the E50F2 and the E150F. Please read both the first and second pages here: http://bgbonline.celicatech.com/90alltrac/MT/MT.htm

Edit: By the way, I misspoke referring to the center diff as open earlier.......clearly we all agree that it is a VC diff. Although I would counter that it is indeed a VC diff lock (non-mechanical, more like an LSD) stby for link.....

 

Okay, I know the 50/50 thing is just semantics. Like you say, conditions are variable. But for the sake of continuity and ease of explanation let's just keep saying 50/50. However, even if you don't read page 1 you should read page 2 in the lower left corner where it outlines that the power flows from Transmission-CenterDiff-FrontDiff/RearDiff. That underscores my point that it is truly full-time 4WD. I think your picture is key. I believe (but I'm not 100% sure) that the long shaft pictured is the "differential side gear intermediate shaft"​.

 

So I went and picked up my new gearbox today.

It was sold to me as "mr2 lsd gearbox", has the selector on the FWD side with the opposite side blocked off with a welsch plug, has a pinion shaft through the diff and is near impossible to make the output shafts spin opposite ways.

What do you guys think?





[video=youtube;rZz56ndRr-k]http://www.youtube.com/watch?v=rZz56ndRr-k&feature=youtu.be[/video]

 

It better be, I paid $300 for it!
I got a set of shafts that look like they're big turbo inners and 162 outers, solid CVs, good boots etc.
Cover is cast aluminium
It's out of an MR2 turbo apparently
S20404112 - What does it mean?
The speedo was removed, I'll have to find a new one.
Drive ring is a creamy dull yellow colour.

The guy I bought it off said he got it to put in his 162, but lost interest in the project.

I know I need the GTE flywheel (which I have) to fit this to a GE, but what starter motor does it need? My 3SGE ones don't fit.

 

Nice gearbox you got there bit expensive ,Exactly what I said our starter's don't fit they to short on the bendix side it's good that have mention that as well .I was told the Camry one fit's there but wait for more info for I am not 100% sure still going to pick mine up as well then will find out.

 

It was cheap compared to what a lot of places want for an MR2 box around here :toetap05

I'll admit I didn't check the wrecking yards first, they want less than $100 for any gearbox but I doubt I would have found a turbo LSD box.

 

Reason why Aaron I said expensive is that you guy's over there sometimes buy a complete celica for $300 lol.The one I am going to get is also from a MR2 turbo a LSD E series not sure what model going to pick it up next week then will see.The price was R1000 maybe $120+- that's the price I got it for.

 

haha yeah I got my last parts car for $350 and my good celica only cost me $700!
$120 is a pretty good price for an LSD E series!

 

Awesome, one of those should be easy to find.

So is the 165 speedo drive the only one that fits or the only one that's mechanical? I don't mind making an electric-to-mechanical converter, I could even just make a 7-segment LCD display speedo.

What would the acceleration and economy be like compared to having the S53 box?

 

That box is a pretty good deal if it's got a LSD and it's in good condition, it's a shame about the ad being so poorly typed lol

My friend has an electric to mechanical box in his 165, I could easily rig one up using a stepper motor once I know the pulse rates of the electric speedo drive. If it's voltage based it'll be even easier and I can fine-tune it.

 

At long last I had the time to go pick my gearbox up here are the picture's I also would like to know what model is it from got the inner shafts as a present lucky me if the no is not visible
it's S 1020 2703 thanks