full time and detroit? (1 Viewer)

anyone here have experience running a detroit, aussie or lock-rite (or similar auto lock) with full time and selectable hubs? I would love to have a detroit in the front with hubs so I can still drive the 80 on the street. (after all I do have soccer practice and groceries to get )

any experience? spare hubs don't take up much room.

once you remove the resistance from the front axle on the 80, you'd have to leave the CDL on all the time to drive it...the t-case system expects power transfer and having zero resistance in front from the unlocked hubs would leave you sitting....

IMO, it would work, but far from an ideal situation...for the $$ of the ARB versus the Detroit, do the ARB and be done with it.

woody said:

once you remove the resistance from the front axle on the 80, you'd have to leave the CDL on all the time to drive it...the t-case system expects power transfer and having zero resistance in front from the unlocked hubs would leave you sitting....

IMO, it would work, but far from an ideal situation...for the $$ of the ARB versus the Detroit, do the ARB and be done with it.

Click to expand...

What's so different on this t-case compared to the borg-warner viscous units? I used to drive those without the front shaft all the time. It would still have resistance, as there would be rotating mass and inertia from the front, all the way out to the hubs, just minus the 160 lbs of wheel and tire.

I have seen WAY too many arb's inop in the field. (air lines, fittings, etc)

j

remove your front driveshaft, take a spin. No dice. Same with a Grand cherokee, had a buddy who lost his front shaft, once he was on pavement he was fine, but on the trail it wouldn't move....wheelspeed sensors basically put all the power to the front....

Robbie did some experiments with lockouts, no shaft, etc...mileage tests mostly, but same stuff applies....

I'm tossin this to 80-series tech too, you'll get way more input there....

woody said:

remove your front driveshaft, take a spin. No dice. Same with a Grand cherokee, had a buddy who lost his front shaft, once he was on pavement he was fine, but on the trail it wouldn't move....wheelspeed sensors basically put all the power to the front....

Robbie did some experiments with lockouts, no shaft, etc...mileage tests mostly, but same stuff applies....

Click to expand...

I could understand that on an electronic 4wd system, but not on a mechanical viscous coupling. (grand cherokee)

you can drive without a front shaft (or rear) you just have to lock the CDL as Woody said, ABS is disabled when the CDL is locked, unlocked hubs disconnect the sensor from the wheel anyway, sensor would be watching shaft speed not wheel speed.


also with one shaft removed, CDl locked and I assume it would be the same with unlocked hubs there is a soft thod or slop area when starting or stopping, at first it felt like severe axle wrap or the squat I had on my 280zx, after feeling/watching the shiftrs I think it is the transfer/tranny/engine asy moving arround, I think with both shafts loaded they counteract eachother with only one shaft loaded it moves the drivetrain assy arround.

CDL- Center Differential Lock. The Center Differential is not that mechanically different than that of the Rear Differential. As in the Rear if you loose traction at one of the ends you go nowhere, with the Center Differential if you loose traction on eirther drive shaft you go nowhere. This is why you would need to use the CDL all the time if you were to put in switchable hubs.

Oh and... Grand Cherokee

landtank said:

CDL- Center Differential Lock. The Center Differential is not that mechanically different than that of the Rear Differential. As in the Rear if you loose traction at one of the ends you go nowhere, with the Center Differential if you loose traction on eirther drive shaft you go nowhere. This is why you would need to use the CDL all the time if you were to put in switchable hubs.

Oh and... Grand Cherokee

Click to expand...

It's still a viscous. diff-lock only splits it 50/50 via a positive engagement viscous works like a torque converter. or did you know that

z80 sounds like your experience with a VC is different than how it is in an 80, in other vehicles you are referencing is the rear shaft directly driven and the front driven through a VC to allow difference in RPM front to rear, no true differential?, I get that impression but don’t know for sure.

in the 80 there is a physical differential in the transfer case, both front and rear outputs of the transfer case can spin at the same RPM as input or one 0 rpm the and the other twice input RPM or anywhere in-between, the two sides of the VC are splined to the front and rear shafts and tend to resist but not prevent a difference in RPM front to rear.

a practical example wile I had my front shaft out I was working on the 80 and unlocked the CDL, forgot about it and hopped in later to go into town put it in reverse and backed up, on the flat part of my driveway the VC had enough resistance to get some power to the rear and it backed up, got to the hill and the vehicle stopped and started rolling foreword again. much more slip than a torque converter, all of the RPM was going to the non existent front drive shaft. Instantly remembered and scalded myself and locked the CDL again. If I had tried longer the VC should have eventually locked up but that is not its intended use.

Some reading that may help

The HF2AV tranfer case (differential and VC info starts on page 65)

Diffs for Dummies (good article bad name)


what year 80 do you have?

Your abosolutely right Z80, it has a VC in there ( provided you have ABS, but you knew that ) and if you stand on the accelerater without one of the driveshafts installed you will be able to move the truck.

Dan, your dogs are gong hungry any time soon I think.

landtank said:

Dan, your dogs are gong hungry any time soon I think.

Click to expand...

Translation?
Dan = dumb ass newbie?


dogs = feet?

LMAO!!! now THAT's funny!

"dan" = cruiserdan on the forum....parts manager for American Toyota, one the banner advertisors on 'MUD, and the cheapest, fastest, and most knowledgable source for OEM Toyota parts, especially oddball stuff (list of ALL our great banner crew is at http://www.ih8mud.com/ads.php)

"dogs" are a long standing joke from many years back about him needing to sell stuff to keep his puppies fat.....

If you check the member list, sort by post count, he's in the top 5...pathetic post whore padder....lol

I suggest you uncouple the detroit locker idea and the 2wd ides and consider them separately. I see two ideas that I think are dubious mutually reinforcing each other in your mind here.

my first question on the locker would be why you would want a front locker first instead of a rear anyway? Is that strictly because you want to save $ with a detroit and want it to be disconnected on the highway? Do you see any advantages to a front locker over a rear?

My second comment is how much using this locker would limit use of 4wd. If a detroit affects the 80's front steering anything like a factory locker it is not something I would want potentially automatically engaging on me on the trail whenever I am in 4wd, and you will be giving up a lot of the 80's capability if you end up cruising trails mostly in 2wd to avoid that problem. Another concern I would have is that an untimely auto-engaging locker might lead to you breaking a birfield.

It sounds like a double compromise to me both on locker capability and location.

There is no doubt that 2wd will get better gas mileage, but I think there is a reason no one on this board has gone your route despite the rising price of gas. Just about everyone who has tried 2wd here reports a loss of handling. That and losing ABS for street use is not something I would do lightly if I lived in Colorado. Not to mention the fact you will have to crawl under and hook up the drive shaft if it starts snowing (or else leave the drive shaft in during snow season and reduce the mileage gains you see since the t-case will be spinning the front axle).

I think at minimum you should try the 2wd before you commit to the detroit locker.

Also, if you don't trust arb's then find a wrecker with factory e-locker'd rear axle and do a swap (there is a write up on this here and at sleeoffroad's site). (or keep your eye on the for sale section here — they do turn up and your old axle(s) will have some value)
https://forum.ih8mud.com/showthread.php?t=32990

I am not looking in any way to have 2wd. Far from it. I have quite a bit of experience in locked vehicles.

I do mostly 7-9+ rated trails, and a front locker is almost always a godsend if not a necessicary (sp).

I also do quite a lot of long off-road trips, (several days) solo or with only one other vehicle, and uber reliability is key, hence my like of the detroit product.

I only want the free hubs to drive it to the trail, on the freeway. I don't build trailer queens.

j

I don't question the use of the Detroit front in the absence of the factory lockers for the purposes you describe, but what you are doing by installing that Detroit is removing AWD no matter how you try to trick it.

If you really want to remove AWD, we should start having replacement transfer case discussions. Why do you want a full time AWD case for 2wd and 4 lo use only? Could you stuff an Atlas II under an 80? If you are going to lose AWD for the only situations in which it is useful (onroad/bad weather), might as well pick up something sweet like a 4.3:1 low range and a gear driven case if you can.

Nay

John, interesting, well if none of those comments slows you down, keep us posted on how it turns out. I don't know what the colorado trail rating system is but I tend to pull the chute at "body damage likely" and I engage the lockers fairly rarely so draw your own conclusions about how applicable my advice is to you .

And now for a thread hi-jack.

Raventai that is an excellent article on the centre diff t-case function you linked to. I will have to read it several times to understand it but that is not because it is written in near flawless japanese in-house engineerese which is nice because it tells me that whoever wrote it knew exactly what they were talking about. What is it and where does it come from.

I think this article also helps explain the difference Raventai mentioned betweem vc applications. http://www.difflock.com/offroad/difflocks.shtml

If I understand all this, some vehicles use a VC as the centre differential and set it up to lock up in certain conditions. Others use a VC to trigger some kind of diff lock in conjunction with a conventional open diff. That is what the 80 system from 93-97 does I think. I don't think this difference alone necessarily explains why an 80 VC does not lock up the rear diff immediately or completely if you pull the front drive shaft. I think the answer is as Raventai notes that the 80 system is set up as a limited slip system designed to vary the power to the front and rear within a finite range to optimize road handling, (and possibly with an engineered delay in response), and not to act as a full diff locker. Toyota engineers probably figured that when you actually needed a fully locked diff you would engage the CDL.

Interestingly I think this article might actually give a good explanation for the infamous difference between AWD and fulltime 4wd based on the diff design. AWD is "part time automatically engaging 4wd" while fulltime 4wd is "full time auto diff locking 4wd" or, in other words, full time 4wd vehicles have a conventional open diff and AWD vehicles do not. Anybody buying that ?

I would also like to know what the VC operating range and sensitivity is. I know you are supposed to keep the same size and model tires on an 80 to avoid burning out the VC by asking it to constantly compensate for a small speed difference between front and rear. It would be good to know what the VC sensistivity is so you would know how much tire size difference is needed to engage the VC.

Okay, maybe I'm going to make a fool of myself with my ignorance here, but I've got to ask...

I like the idea of a limited slip differential (or more specifically a torque biasing limited slip differential. I don't get why one could not put one in either the front or the rear of a land crusier.

Why would a auto locking differential "disable the 4 wheel drive"?

I've got a truck ('03 F250) that has 4 wheel drive and also a limited slip differential (rear diff). As far as I can tell, the two systems are not mutually exclusive.

It seems to me that you would not get the benefit of an e-locker, or an air locker, since you would never get 100% lockup on demand of a switch, but what you would get is a good torque bias across the two wheels that use the limited slip. That would probably suffice for those of us that don't rock crawl.

Plus it is $300 rather than the $2000+ of a e-locker retrofit or ARBs.

What am I missing?

Charlie

Still trying to figure out whay an aussie locker wouldn't be a bad idea for my street driven (and some primitive dirt road driving) 80...

a 10 on the colorado scale is equal to a 5 on others. I usually start on "body damage likely"

j

charlie

an automatic locker would not by itself disable the fulltime 4wd system, but I think most folks would not want to drive with one in a DD on the street especially in wet or ice? John is thinking of switching to part time 4wd if he installs an auto locker for this reason, and others have replied to him on the basis he will be doing that if he goes with an auto-locker.

There was a post recently by Bjowett about LSD installations. You can put an LSD in the front axle of an unlocked 80 cheaply using a late 80's supra LSD but it is not a torsen system. There are also pricier options out there. However, an LSD is not compatible with the factory front/rear e-locker system so this is only something for people without f/r lockers standard. Personally, I think an 80 in 4-hi handles great on dirt roads where an LSD front or rear might help other vehicles. It has a centre LSD courtesy of the VC which makes the 4wd system work very well or "thus providing the excellent vehicle's driving performance over slippery terrain such as rough or snowy road" to quote the engineer in Raventai's article. I am sure an LSD up front or in back would help somewhat, but I think for all the effort and expense I would sooner swap for factory locked axles or go with an arb locker.

z80 said:

anyone here have experience running a detroit, aussie or lock-rite (or similar auto lock) with full time and selectable hubs? I would love to have a detroit in the front with hubs so I can still drive the 80 on the street. (after all I do have soccer practice and groceries to get )

any experience? spare hubs don't take up much room.

Click to expand...

It would seem the answer in No, no one has any experience with this setup.

You seem to think outside the box and new ideas are always welcome.

Sometimes we tend to look at the post count and let that influence our responces. I know I was trying to cover the basics and be sure you understand them. With your extensive back ground I think you understand the pros and cons and I'm interested in the success of that kind of setup.

Let us know.