FZJ80 Center Diff Lock Issue?

[40-Overlander]

Today when trying to engage 4-Lo I noticed there was a clicking noise when trying to make a turn. Center Diff lock engaged like it was suppose to but I've never experienced the clicking noise and tires seemed to be locked up when trying to turn. The noise came from the front of the vehicle...possibly from the passenger side. Once I noticed the clicking noise I put the vehicle in neutral and shifted back into 4-Hi. The center diff did not disengage and it took some hard steering to disengage it. Again causing the clicking noise and tires seemed to be jammed up. Once the center diff lock was disengaged the clicking noise went away along with the harsh steering. Has anyone ran into an issue like this before? Thanks

 

[foeix]

Were you on a surface where the wheels could hook up - e.g. pavement, gravel or compacted dirt? Then normal. The center diff should not be locked unless you has noticeable wheel spin, e.g. mud, sand etc.

 

[40-Overlander]

So all of those symptoms are normal for the Land Cruiser, even the CDL not disengaging right away on 4-Hi?

I've read up on people getting the CDL switch so that they can use CDL while in 4-Hi in the snow. I definitely understand the concept of not locking a front or rear diff up when on hard packed surfaces but I don't understand why the CDL would matter. Since the front and rear diffs are open, power would still transfer to which ever tire was easier to spin. Power would just be split 50/50 from the front and rear axles...right?

Thanks for the help, I'll see how it acts on a more loose surface.

 

[40-Overlander]

Yup, amateur hour over here. It's nice and rainy over here and tried it out on some muddy/sandy soil. No noises and CDL engaged and disengaged like it was suppose to.

 

[Klierslc]

Seems like you got if figured out, but the driveline windup is due to the different paths that the axles take through a turn. Different paths=different distance=different driveshaft speeds--hence the binding up. The clicking is in the birfield (CV) joints on the front axle. They don't like to be wound up, but the clicking just indicates that they have a little play...normal.

The CDL doesn't disengage right away because it has a little motor and if there is tension wound through the drivetrain it will prevent the locking collar from unlocking until things are turning freely.

 

[Box Rocket]

Sounds to me like you're question has been answered but one note on the clicking birfs, clicking isn't "normal" in the sense that they should click but I suppose it's "normal" for a worn birf to click. Some people will swap the birfs side to side so they run against the opposite surface inside the joint to eliminate clicking (temporary fix) on worn birfs. This can help you get a bit more time out of them before they need to be replaced.

 

[40-Overlander]

Adam/Klier,

Thanks for the posts, that was something that I feared when I first heard the clicking noise. It was the first time I experienced that in 4-Lo and went away after I was able to disengage the CDL. From what I've read on the Ih8mud forum when you hear the clicking noise it's time to replace the birfs. I haven't heard anything since last Friday when daily driving and testing 4-Lo/CDL out in the mud on Sunday.

I guess what I'm trying to find out now is, will there be some sort of catastrophic failure while driving if I don't remedy this asap or is it something I should listen to see if it worsens and fix it once I have the $/time to fix it?

Also still a little confused how there would be more stress on the axles with the CDL on. With open diff's why would there be additional stress on the axles? shouldn't power still transfer to the wheel with least resistance?

 

[Klierslc]

--So, clicking birfs is a indicator of wear and/or need to service. However, that type of clicking will be heard in parking lots and driveways under normal operation. The clicking that you are describing while under load in low range is something that all three of my 80s have had to some degree, just not very often--for instance, my 94 never clicked a day in its normal life or off road life, but I had it bogged down in sand one day and it started clicking at me like an angry Geiger counter. The others have done the same in similar situations but only when under a lot of stress and with the steering wheel turned. So, the answer to your question is: Service your birfs when they start weeping from the knuckles or start clicking on road, they will not catastrophically fail due to some clicking while off road under load.



--For the CDL issue, your axle is a mechanical system--it can only output the amount of movement that is input into it via the driveshaft. If the two axles are traveling different distances, their inputs must be different. The unlocked center diff allows the driveshafts to turn at different rates much like a regular diff allows wheels to turn at different rates. When the CDL is locked, the driveshafts must turn at the same rate--if the axles are trying to go different distances, it causes tire scrubbing and/or drivetrain loading/windup. When on a lower traction surface, this isn't an issue, while on pavement, it is hard on things.

 

[REDrum]

I've read up on people getting the CDL switch so that they can use CDL while in 4-Hi in the snow

The pin 7 mod is damn handy to have. Use CDL all the time in hi and often disengage CDL when in low.