center diff lock question

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arbetrader

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I'm thinking of buying an 80 (locked of course), and most of them I'm seeing don't have a locking center diff, although some have it.

I've also noticed a number of you cruiserheads have installed a factory button on the dash to lock it manually.

Without it, does that mean that if I lock the front and rear diffs, the vc will still be transferring power unequally to the front and rear?

Does this significantly affect offroadability? What are your experiences with and without it. Do I really need it?

I'm thinking that without it, if I"m rockcrawling, and either the front or rear wheels are in the air or without traction anyway, I could be spinning helplessly... Is this true? Any help would be appreciated. Thanks!
 
All US spec 80-Series were equipped with a locking center differential.
The 91-92 models came stock with a dash switch to enable or disable the CDL.
The 93-94 non-ABS models came stock with a dash switch to enable or disable the CDL. Edited
The 93-94 ABS models came stock without a dash switch. Enabling the CDL is automatic when the Xfer is shifted to Low Range. Edited
The 95-97 Models came stock without a dash switch. Enabling the CDL was done automatically when the Xfer is shifted to Low Range. Edited

Many enthusiasts with the 93-97 models have added a CDL dash switch and done the Pin-7 mod. This allows manual control over the CDL like the 91-92 models. The Pin-7 mod also restores the factory tranny shift-points when in low range. There are other nuances of the Pin-7 mod and the CDL switch but that is all you really need to know for now.

The 93-97 models were *available* with electronically locking front and rear differentials. This OPTION was on ~7% of the US production of 80-Series. There were no versions/models/LX/40th/CE or anything else that came STOCK with the F&R locking diffs.

Please do some FAQ reading (e.g. Diffs for Dummies) and searching for more answers to your questions.

-B-
 
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Hmm.... I've been reading various references to the CDL switch (making your defroster button into a CDL switch, etc.)

My 94 (no lockers) has a "Center Diff Lock" button on the dash.

Is it 93-97 or 95+ w/o the CDL switch?
 
The information in post #3 is correct. Edited

As far as "other" switches that work.... I have heard that the Hazard switches will work. I have not heard that the defroster switch will work but until a recent thread, I have never heard of anyone trying a defroster switch. Try it and let us know.

-B-
 
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I have the CDL switch on the dash. Does that mean that I have the 7 pin?
 
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According to my FSM, if you do not have ABS you will have the CDL switch on the dash for a 94 model. Not sure about other years.

So are the factory lockers and ABS (and leather) an "all or nothing" package? If so, no leather = no lockers = no ABS = no pin 7 mod required.
 
zcruiser said:
According to my FSM, if you do not have ABS you will have the CDL switch on the dash for a 94 model. Not sure about other years.

So are the factory lockers and ABS (and leather) an "all or nothing" package? If so, no leather = no lockers = no ABS = no pin 7 mod required.
Click to expand...

There is no pattern, lockers are an OPTION and lockers are completely independant of all other options.

NONE, ZERO, NADDA 93+ FZJ80s sold in the US had a CDL button from the factory NOR the dealer, if you have one a PO installed it. EVERY FJ/FZJ80 has a center diff lock actuater that without the pin7 mod is automatically engaged when the t-case is shifted into low. FR/RR diff locks only work when the center diff is locked no matter how you lock it.
 
alkaline747trio said:
There is no pattern, lockers are an OPTION and lockers are completely independant of all other options.

NONE, ZERO, NADDA 93+ FZJ80s sold in the US had a CDL button from the factory NOR the dealer, if you have one a PO installed it. EVERY FJ/FZJ80 has a center diff lock actuater that without the pin7 mod is automatically engaged when the t-case is shifted into low. FR/RR diff locks only work when the center diff is locked no matter how you lock it.
Click to expand...
Lockers are an option, but require the axles that came with 4wheel disc/ABS, which a handful of 93-94 did not have. There is no correlation to leather interior.
 
Sorry, I know I'm new to 80s, but I want to differentiate between F&R lockers and center diff. I don't have F&R lockers, but I do have a center diff and I do have a CDL switch on the upper part of the dash that says "CENTER DIFF LOCK" (not an icon) and is is described in my owner's manual and the FSM as a switch which is ONLY on vehicles w/o ABS (for 94, anyway).

This is NOT the rectangular CDL switch that can be purchased from Slee.
centerdiff_150.jpg


This is on the curved upper part of the dash and is the same shape as the defrost, ECT, and antenna up/down buttons. I think if you have ABS, you DON'T have this switch, according to my owner's manual and FSM.

FZJ80_CDL.JPG
 
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619TOY said:
Actually, I think that the pin 7 mod prevents the center diff from locking automatically when placed in 4 low?
Click to expand...

CDL is automatic in 4L, and pin 7 mod fools the ECU into thinking it's in 4L so allows the center diff to be locked even when in 4H.
 
zcruiser said:
Sorry, I know I'm new to 80s, but I want to differentiate between F&R lockers and center diff. I don't have F&R lockers, but I do have a center diff and I do have a CDL switch on the upper part of the dash that says "CENTER DIFF LOCK" (not an icon) and is is described in my owner's manual and the FSM as a switch which is ONLY on vehicles w/o ABS (for 94, anyway).

This is NOT the rectangular CDL switch that can be purchased from Slee.
centerdiff_150.jpg


This is on the curved upper part of the dash and is the same shape as the defrost, ECT, and antenna up/down buttons. I'll add a pic in a few minutes if I can find my digital camera. I think if you have ABS, you DON'T have this switch, according to my owner's manual and FSM.
Click to expand...
That makes sense, though I haven't seen it before on a 93-4. Assuming you don't have 4 wheel disc brakes, or ABS?
 
firetruck41 said:
That makes sense, though I haven't seen it before on a 93-4. Assuming you don't have 4 wheel disc brakes, or ABS?
Click to expand...

Right... Drums only on the rear, no ABS.
 
zcruiser said:
CDL is automatic in 4L, and pin 7 mod fools the ECU into thinking it's in 4L so allows the center diff to be locked even when in 4H.
Click to expand...
You had me second guessing but I still think I'm right. The switch is all thats neccessary to lock the center diff., even in hi. The pin 7 mod allows you to be in 4 lo un-locked.https://forum.ih8mud.com/showthread.php?t=2151
 
619TOY said:
You had me second guessing but I still think I'm right. The switch is all thats neccessary to lock the center diff., even in hi. The pin 7 mod allows you to be in 4 lo un-locked. https://forum.ih8mud.com/showthread.php?t=2151
Click to expand...

Sorry, my bad. Guess I mis-read the function of the mod and the diagrams in the FSM...

I was going on this description on the Slee website re: Pin 7 mod...

What you have just accomplished is you have interrupted the signal from the transfer case that tells the lock ECU that you went to low range but you are still sending a signal to the transmission ECU telling it that you ARE in low range. Therefore the transmission will shift in the correct low range pattern. In addition you now have true manual control over center diff locking. It only locks when you tell it to without regard to transfer range selection.

Without ABS, I think I have full control over the center diff w/o the pin 7 mod.
 
alkaline747trio said:
fire, ABS doesn't matter...yes 4wheel discs (specifically the FF rear axle) correlate to the lockers, but if you ordered lockers the FF 4wheel discs were included.
Click to expand...

That's basically what I meant, ABS doesn't matter but you can't have lockers w/out it, you get ABS with the FF axle/disc brakes.
 
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