Centre diff 80 series

Submitted: Saturday, Aug 11, 2012 at 23:25
ThreadID: 97379 Views:8402 Replies:8 FollowUps:5
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Gerday again,
This has probably been discussed to bits, but..... just bought a '97 40th anniversary L/C... dual fuel,auto. Do people think this is worthwhile doing....

The 80-series after around August 1992 introduced a viscous coupler over the centre differential. In order that this coupler doesn’t get stressed when in low range, Toyota deleted the manual centre diff lock switch and instead linked its operation to the transfer lever, locking the diff when in low range and opening it in neutral or high.
While this protects the transmission from erroneous usage, it does rather limit options, for example using low range when maneuvering trailers on hard surfaces etc. This needs to be rectified.
In order to bring the CDL back under driver control, two things are needed: Firstly a centre diff lock switch, and secondly a way of preventing the centre diff lock control ECU from knowing when it’s in low range. Rather than explain the process in extreme detail, Slee Off Road have a brilliant how-to here. This procedure is known generally as the Pin-7 mod, as it’s pin 7 on the centre diff lock ECU connector that carries the “low range engaged” signal.
Toyota conveniently left the centre diff lock switch loom tied back under the dash, so all that is required is to fit the new switch, connect the loom, and disconnect pin 7 from the transmission control ECU.
Once done, the CDL can be engaged and disengaged manually in high, neutral or low. Simples!
One other thing to do is to modify the ECT (main gearbox) ECU to allow the shift pattern to be switched between the factory-intended low range pattern (which is absolutely nuts – the engine revs to 3500 RPM before shifts occur, at which point they near enough break your neck due to the ferocity). This mod can be accomplished in a similar manner to the CDL mod in that a pin to the ECT ECU needs interrupting, however I haven’t yet got aroudn to digging the ECU out from under the dash…

I do the occasional beach/dune driving, which is where I thought this may come in handy? (BTW I have a FJ60 with stock diffs as well). This will be our camping bus with the family and I plan on going to some fairly remote spots as time allows. This is my first AWD cruiser and auto. Is it a waste of time and should I be thinking more about diff locks? Two? or if just one, which end?
Thanks!
Wazza
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Reply By: Wayne's 60 - Sunday, Aug 12, 2012 at 02:49

Sunday, Aug 12, 2012 at 02:49
Hi Wazza,

As I understand it, Toyota removed the CDL on the ABS fitted vehicles ..............
and probably for a very good reason.

Maybe doing a 4WD training course in your "new to you" vehicle BEFORE you go modifying it will be the best course of action.

Insurance companies can take a dim veiw of some modifications.

Cheers,
Wayne & Sally.

AnswerID: 492739

Reply By: Work2Travel - Sunday, Aug 12, 2012 at 07:47

Sunday, Aug 12, 2012 at 07:47
Hi wazza, I have the same year model vehicle as you, except manual & factory turbo diesel. I have installed the centyre diff lock switch, its easy to do and not very pricey either. I didnt do the pin 7 modification that you speak of because I am happy to have the CDL locked when in low range, but you may have reasons why you want the CDL open in low range. I havnt heard about the auto ECU modification that you speak of, you might want to ask that question on lcool website. I also have front and rear air lockers, iv been all over this great country of ours, and only used them a handfull of times in anger, but when iv needed them, they are worth their weight in gold.
AnswerID: 492748

Reply By: Big Woody - Sunday, Aug 12, 2012 at 07:56

Sunday, Aug 12, 2012 at 07:56
Hi Wazza,

I did the 7 pin mod to my 80 as my farm has excellent traction due to solid rocky outcrops and big tyres, but much of it is too steep for high range and I was getting wind up when using low range.
Took all of 10 minutes to do the mod and it was fantastic.
It is much better having control of when when the CDL is activated.

Can recommend the 7 pin mod.

BW
AnswerID: 492749

Reply By: Andrew & Jen - Sunday, Aug 12, 2012 at 08:39

Sunday, Aug 12, 2012 at 08:39
Hullo Wazza
With an auto, I don't have any problem manoeuvring trailers, vans, etc just using 1 or R in HR. Putting it in 1, rather than D, decreases the slip in the auto by increasing the pressure. It is noit as if you are doing this for sustained periods of time. I monitor the auto trans oil temp and no issues there.
A manual trans would be another story as riding the clutch excessively would be an problem
Cheers
Andrew
AnswerID: 492752

Reply By: landseka - Sunday, Aug 12, 2012 at 11:04

Sunday, Aug 12, 2012 at 11:04
I too did the Pin 7 mod when I had my 80 series 40th Anniversary . I had need to reverse my caravan up a steep driveway coming off the road outside our then house and wanted low range without wind-up. The quick mod worked perfectly for me.

I never heard of the ECT mod and don't know that I would have bothered had i known.

Cheers Neil
AnswerID: 492760

Reply By: Nomadic Navara - Sunday, Aug 12, 2012 at 17:48

Sunday, Aug 12, 2012 at 17:48
I don't think it matters what vehicle you have, the ability to have an open diff/viscous coupler in low range is the way to go when manoeuvring a van onto site. That is the thing I miss most since changing from a Disco to a D40.


PeterD
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AnswerID: 492773

Reply By: wazza200571 - Wednesday, Aug 15, 2012 at 23:43

Wednesday, Aug 15, 2012 at 23:43
Thanks everyone for your replies.I do a fair bit of sand/beach work and was thinking having use of 4H with a locked centre diff would be good (As well as the other scenarios when/if needed). Thoughts on that? As money allows I'd like to stick air lockers F & R as well.. that should cover all bases I'd think!
Cheers,
Wazza
AnswerID: 492953

Follow Up By: Big Woody - Thursday, Aug 16, 2012 at 07:03

Thursday, Aug 16, 2012 at 07:03
Wazza,

Don't you have the diff lock button on your dash for the purpose of locking the centre diff in 4H?

BW
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FollowupID: 768566

Follow Up By: wazza200571 - Thursday, Aug 16, 2012 at 09:37

Thursday, Aug 16, 2012 at 09:37
Narrr, its a '97 , doesn't have one......'The 80-series after around August 1992 introduced a viscous coupler over the centre differential. In order that this coupler doesn’t get stressed when in low range, Toyota deleted the manual centre diff lock switch and instead linked its operation to the transfer lever, locking the diff when in low range and opening it in neutral or high.'
Hence me wanting to fit one.
Wazza.
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FollowupID: 768574

Follow Up By: Big Woody - Thursday, Aug 16, 2012 at 10:26

Thursday, Aug 16, 2012 at 10:26
Ahhh....now I understand.

For running locked in high range there is nothing you need to do as the viscous coupler acts as an automatic diff lock and will lock the diff as soon as there is there is enough slip for it to engage.

As far as running unlocked in low range the 7 pin mod should do everything you need it to do but not having owned an 80 with the viscous hub I am sure others will be more well versed than I am to know whether the 7 pin mod works with your model.

BW
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FollowupID: 768579

Follow Up By: wazza200571 - Friday, Aug 17, 2012 at 22:19

Friday, Aug 17, 2012 at 22:19
Cheers BW...
By fitting a switch though, I can have control of the locking over the CD in H and L, right? Thats how I'd like it to be.
Automatic devices are nice, but I prefer to KNOW its locked, if you know what I mean? Do these CD's wear out like LSD's do? If its worn, will it still lock, either automatically or electronically?
Cheers,
Wazza.
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FollowupID: 768678

Reply By: wazza200571 - Thursday, Sep 06, 2012 at 20:12

Thursday, Sep 06, 2012 at 20:12
Just a quick follow up on this...
Does anyone know who's selling these switches (Toyota Part No. 84725- 60040, the rectangle shaped one), Besides Toyota? They want $220. Have rung around Perth wreckers, no luck so far. May have to start trying interstate. Found 1 on E-bay USA! But he doesn't ship International... Sent him an e-mail to see if I can persuade him, haha!
Cheers,
Wazza.
AnswerID: 494375

Follow Up By: rainbowprof - Wednesday, Sep 19, 2012 at 00:49

Wednesday, Sep 19, 2012 at 00:49
keep your eyes peeled. I got one off ebay for $20 and have seen them advertised several other times for around that price.
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FollowupID: 770880

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