LOW WITHOUT CENTER DIFF LOCKED

Beowulf · 04-10-03, 05:49 AM

Chris,
That looks too clean underneath to be a 1994 truck with 140,000 miles.

Tell me you steam cleaned the undercarriage for those photos.
-B-

Chris_Geiger · 04-10-03, 06:47 AM

I had been looking for 80 for months and when I saw this one I jumped on it and got it that same day. It's the cleanest I saw and only paid $12K for it. The inside is like new. Not a single dent or ding on the body. It's been in California all it's life and has no signs of rust anywhere.

I don't think the 4wd had ever been used, so the center diff lock was stuck but all it needed was a little TLC and a diff lock switch.

I pulled the electric diff locks out and they were clean, never had water in them, both units are like new.

Now it's time to sell the rear seats and running boards!

Strider · 04-10-03, 08:34 AM

Sorry for the stupid question, but the only benefit listed for low gear without the center diff locked is a higher rev limit for gear switching.

The 'pwr' switch seems to provide that benefit already..? [I haven't checked it decelerating, but accelerating it clearly provides higher rev points]

This whole discussion brings up another point I've wondered about. Supposedly when you're in low and the center diff is locked, it will automatically disengage over 5 mph. [according to my owner's manual] I tested it and it did disengage over 5 mph. I don't understand this feature. &nbsp

oes Toyota assume you'll never need your diffs locked over 5mph? :dunno:

Matt

cruiserdan · 04-10-03, 09:04 AM

The power switch does move up the shift points, when I was playing around I tried that and it did not seem to be quite the same as when in low(my experience).
As far as the center diff unlocking above 5mph, it does not.
You may be thinking about the front and rear difflocks. They will not LOCK if the vehicle speed is above 5mph. They will however, stay locked if the vehicle speed exceeds 5mph after locking.
In addition, the center diff must be locked before the difflock ECU will allow locking of ethier diff.
If the center diff lock is disengaged with the diffs locked, the diffs will also unlock regardless of the diff lock switch position.

Chris_Geiger · 04-10-03, 09:27 AM

Quote:

Sorry for the stupid question, but the only benefit listed for low gear without the center diff locked is a higher rev limit for gear switching.

Matt

The primary reason for wanting the center diff open in low range is for low speed maneuvering on hard surfaces. Sometimes it's handy to be able use lo range but if your turning tight the drive line can bind up. With the center diff open you can still turn on hard ground. Real handy for backing up trailers in tight spaces.

Photoman · 04-10-03, 09:31 AM

CDan,

Quote:

If the center diff lock is disengaged with the diffs locked, the diffs will also unlock regardless of the diff lock switch position.

Can you clarify that as it relates to removing the wire from pin 7. I.E. If I am controlling all the locking and unlocking of the center diff with the dash switch and with the wire removed will the front and rear disengage above 5 MPH if I have the center diff disengaged? *:dunno:

Also, it is handy to have the center diff disengaged when trying to negotiate logging road switchbacks. It is nice to have the rear locked up but not be bound in the middle.
Bill

Beowulf · 04-10-03, 10:07 AM

C-Dan,

A followup question to Photoman's:

Assume you have Rear locked (w/OEM diff locks), the CDL switch, the center diff locked, low range, under 5 MPH.

1. If you unlock center diff via CDL switch will it unlock rear?

2. If you then lock center diff via CDL switch will it relock rear?

3. Same questions and scenario with both F&R?

-B-

cruiserdan · 04-10-03, 10:28 AM

Bill,

Bear with me while I set this up. The front and rear diffs will only lock with the center diff locked first. They do not know or care how the center gets locked, only if it is locked. By installing the switch and pulling the wire from pin 7 you have converted center locking to manualy selected by you. The front and rear diffs still behave the same way, they wait for a locked center and a vehicle speed below 5mph before they are "armed" so to speek. Once the front and rear diffs are locked they will only un lock when the rotary switch is turned Or the center diff is unlocked (manualy by the operator in this case). In other words the front and rear diffs couldn't care less how fast you drive AFTER they are locked, they stay locked until told otherwise.
As the system is currently configured you can not lock the rear unless the center is locked. Also you can not lock only the front, the rear must be locked first. It may be possible to fool the diff lock ECU in a fashion similar to what I discovered with the center diff lock. I know that there is a vehicle speed sensor feed to the diff lock ECU that could be deleted, that would eniminate the blocking of the locking above 5mph. I do not think I would do that as a diff locking up at higher speeds can get spooky. Also it would have no impact on enableing locking the front or rear without the center first locked. You would need to "fool" the diff lock ECU into thinking the center was locked even if it wasn't. then you could lock just the diffs. to take it a step further you could also probably fool it to think the rear was locked if you just wanted to lock the front.
I will look at the EWD's and see if it looks doable.......

Regards....Dan

cruiserdan · 04-10-03, 10:35 AM

-B-

Yes, unlocking the center does unlock the ends.
The ends will re lock along with the center if you left the rotary switch on AND you are traveling under 5mph.

IS EVERYBODY BORED YET?

Sometimes I get carried away.............

Beowulf · 04-10-03, 11:02 AM

C-Dan,

I'll have to think about it a bit but offhand it seems like this is a useable feature offroad.

For example: *You could put it in Low, lock the center diff via CDL switch, then lock the rear via rotary. *Now, just use the CDL switch to unlock center and rear, wheeling away until you approach an obstacle, then press the CDL and both center and rear will lock up. Pass the obstacle and press CDL to unlock both. *In situations where you don't want the rear diff locked (e.g. off-camber cross-hill descent in snow) you could unlock the rear.

I usually air down and engage CDL when the PT 4wd guys turn their hubs. *I'm wondering if this might be a better approach.... *Any thoughts?

-B-

Gumby · 04-10-03, 11:28 AM

The center diff will probably unlock first. I wonder how well the rear will unlock without power going to it. Maybe better.

cruiserdan · 04-10-03, 11:58 AM

Gumby,

* *the power to lock and unlock the diffs is not sourced from the center. The center is only the trigger. The diff lock ECU tells the diffs to unlock when it looses the center lock signal. the speed with which the diffs unlock is governed by how "loaded" they are with windup. They will unlock as soon as the load equalizes accross the diff.

In my experience, the average time it takes to unlock a diff that is not wound up is under 2 seconds. In addition, the average lockup time on a diff with the dog clutch lined up is also under 2 seconds.

Beast II · 04-11-03, 08:41 AM

Cruiserdan:

I installed the diff lock switch on the dash, removed the kick panel and found the cigarette box sized relay behind the ECU. Upon looking at the harness, there were two black wires with a blue stripe - kind of reminded me of The Abyss. There was a fairly thin one (maybe 18 guage) and a thicker one (maybe 12 guage) - both black with blue stripe. I cut what looked like the #7 pin wire (the thin 18 guage wire) and nothing happened. The diff lock light on the dash no longer lights up though when in Low Low or with the switch depressed and I'm wondering if this was the wrong wire and if so, did I screw something up in the electrical system ? Should I have cut the thicker wire ? What does the one I cut do ? I spliced the wires as best as I could, but given the precarious area to work in I fear the splice was not the best. I'm leaving on a two day trip to the mountains, so I'm a bit nervous.

Thank you for your help.

Matt

???

Gumby · 04-11-03, 10:05 AM

Quote:

Gumby,

* *the power to lock and unlock the diffs is not sourced from the center. The center is only the trigger. The diff lock ECU tells the diffs to unlock when it looses the center lock signal. the speed with which the diffs unlock is governed by how "loaded" they are with windup. They will unlock as soon as the load equalizes accross the diff.

*.

That's what I meant. I wonder if unlocking the center first will let the rear unlock easier or not because the load will be different.

cruiserdan · 04-11-03, 10:08 AM

Matt,

*There is 1 black wire with blue tracer in *pin 7.
There is 1 blue wire with black tracer in pin 3.
That one is the power wire, I think maybe you got that one.
Did you leave the low 4 position switch plugged in at the t-case?(it should be).

As you look at the open end of the connector, the cavities are numbered thusly:
* * * * * * * * * (top)
* * * * * * * * 1,2--3,4
* * * * * * *5,6,7,X,9,10

* * X represents an open cavity.

* report back...............Dan

cruiserdan · 04-11-03, 10:12 AM

Gumby,

OK, I see what you mean.

In my experience it doesn't seem to make much difference.
I can imagine that in some cases it may make a difference.

Beast II · 04-11-03, 10:37 AM

Quote:

Matt,

*There is 1 black wire with blue tracer in *pin 7.
There is 1 blue wire with black tracer in pin 3.
That one is the power wire, I think maybe you got that one.
Did you leave the low 4 position switch plugged in at the t-case?(it should be).

As you look at the open end of the connector, the cavities are numbered thusly:
* * * * * * * * * (top)
* * * * * * * * 1,2--3,4
* * * * * * *5,6,7,X,9,10

* * X represents an open cavity.

* report back...............Dan

Cruiserdan:

I think I may have gotten the wrong one. All I remeber is that there were two different sizes of wire (with black & blue) and I cut the smaller of the two. Assuming I didn't splice the power wire back together correctly, will anything go wrong ? Transfer case problems etc ? The diff still locks up in low low, just no light on the dash. Perhaps that wire powers the light on the dash ? I haven't touched the plug on the transfer case at all.

Thank you -

cruiserdan · 04-11-03, 10:47 AM

Matt,

*I don't think so. how do you know the diff is locking? Do you get a bind on a hard surface..ETC? *One other thought, is the dash switch plugged in fully?

*Lastly, do you have a fax? *PM me with the number and I will fax a page of the EWD to you................

* * * * * * * * * *Regards..........Dan

CodyRx7 · 09-04-06, 01:25 PM

Question about the CDL switch...

Does installing this allow you to lock the center diff in high gear - or is this mod only to allow you to access low range without the locked center?

firetruck41 · 09-04-06, 01:31 PM

Allows you to engage/disengage in hi or low, at your command.

-Spike- · 09-04-06, 01:40 PM

Quote:

Originally Posted by firetruck41

Allows you to engage/disengage in hi or low, at your command.

Actually, the switch alone only gives you 'command' over the CDL in high range. In low range the CDL will be locked regardless of switch position, as was stated earlier in this thread. you lazy bastards.

The 7-pin mod along with the CDL switch gives you complete control in high and low ranges.

-Spike

CodyRx7 · 09-04-06, 01:54 PM

So currently, stock, if I want to lock the CDL, I have to switch the lever into LOW range...

If I install this switch and do the described 7 pin mod, I can be in regular high gear, and press the new button, which will lock my center diff in high?

I'm curious because I find some trails where I get much better traction with the center locked, but I can only drive what seems like 3 mph...

firetruck41 · 09-04-06, 02:24 PM

Quote:

Originally Posted by -Spike-

Actually, the switch alone only gives you 'command' over the CDL in high range. In low range the CDL will be locked regardless of switch position, as was stated earlier in this thread. you lazy bastards.

The 7-pin mod along with the CDL switch gives you complete control in high and low ranges.

-Spike

I'm losing it! Yes, my comment is with pin 7 mod as well, I guess I just consider it part of the same mod

94landcruiser · 09-04-06, 02:35 PM

This was among the simplest, most gratifying, CHEAPEST

mods I have ever done.

I suggest (at least for 94's) if you hate the key in alarm you remove the box while you are doing pin7 as the damn thing is behind the module removed to perform the mod.

I had to take everything apart a second time and I really hated that.

desertdude · 09-04-06, 05:30 PM

damn this is an old thread

CodyRx7 · 09-04-06, 06:35 PM

Geez, ya use an old searched thread and its OLD....

But if you start a new thread....you should have searched....

(cries)

94landcruiser · 09-04-06, 07:47 PM

Quote:

Originally Posted by CodyRx7

Geez, ya use an old searched thread and its OLD....

But if you start a new thread....you should have searched....

(cries)

It's always sumptin.

-Spike- · 09-04-06, 08:43 PM

Quote:

Originally Posted by CodyRx7

So currently, stock, if I want to lock the CDL, I have to switch the lever into LOW range...

If I install this switch and do the described 7 pin mod, I can be in regular high gear, and press the new button, which will lock my center diff in high?

I'm curious because I find some trails where I get much better traction with the center locked, but I can only drive what seems like 3 mph...

If you install the CDL switch, which is a simple matter of pulling the dash face off and plugging the switch into the existing plug- the one that's there, ready and waiting for your hot little switch, from the factory- you will be able to lock the CDL in high gear. It will automatically lock in low gear, whether or not you have a switch. If you then do the 7-pin mod, you have the choice of running with the CDL unlocked or locked, high or low range.

You do NOT have to do the 7-pin mod to be able to lock the CDL in high range.
All this information is in the thread, READ IT Cody. Goddammit.
-Spike