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Discussion Starter #1
New guy, First post (obviously) So I'll try not to confuse anybody or myself.

I just picked up a 1987 RRC. I intend to use about 50/50 on road/off road. This is my 2nd RRC. My first one was a 1991 that I owned and heavily off-roaded for about a year. It was about a year and a half ago that I sold that one.

I didn't join the forum then because the 91 performed flawlessly! It was amazing off road. In stock form with mud tires, I could easily keep up with my buddies that have lifted jeeps. I fact I don't ever remember getting stuck and needing a pull out. I regretted the day I sold it continuously up till last week when I got the 87.

Ive taken the 87 out in the woods once so far and to my disappointment, the 4WD is very unpredictable. Twice I got stuck in very easily passable terrain because the truck was not "in" 4WD. It would get stuck with only one rear wheel spinning (understandable with open diff) but neither of the front wheels were doing anything. One of those 2 times I was stuck, the front axle was on high/dry ground. But they did not pull out, Just the one wheel spinning in back.

Whereas, other times the fronts were definitely doing work. I still have the mud on my hat to prove it. The classic "look out the window to see if the fronts are spinning" move. They were definitely spinning! lol.

So...I started doing research about my transfer case situation. If I understand correctly, I have the LT 230T case. Gear driven without the viscous coupler. My symptoms should be mechanically impossible without the transfer case exploding right?

I would think that the 91 viscous coupling transfer case would give me these types of problems, but it never did.

So here is where my ignorance builds upon itself :

The whole night I was in "HI" range. I think. Just like driving on the street... The "hi lo" range shifter is broken at the moment and the shift knob is unthreaded and missing. Is the 87 selector simply "HIGH-NEUTRAL-LOW" like the 91 was or is there a "part time-full time" like a Jeep? As far as I know the 87 Rover is 4WD-AWD all the time even in high range right?
The range selector was also broken in the 91 when I first got it. I was able to repair it and intend to do so for the 87 as well.

Its definitely annoying not knowing if the 4WD is working properly or not. Please help me understand whats going on here.

Thanks!!
 

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Both are full time 4WD, but the LT230 and the BW handle the torque bias in different way.

The WB as you state uses a VC to bias the drive torque. This is based on speed differential between the 2 axles. With a low speed reference between the front and rear drive shafts the VC will allow slip. As the difference in speed increases the fluid in the VC increases in viscosity and transfers additional drive torque to the slower moving driveshaft. This is all handle by the VC without any input from the driver.

The LT230 has a manual center Dif lock. With the LT230 UNLOCKED it functions just like the open Dif in the axle and will apply the same torque to the front and rear drive shaft regardless of drive shaft speed. This will allow any difference in driveshaft rpm from same speed (while driving straight down the paved road) to one axle not turning and the other spinning wildly (while stuck as in your case). The transfer case lever for the LT230 has the Lo-N-Hi like your 91 but also has a side movement to LOCK the center Dif. In the LOCKED position it manually locks the center Dif so that the front and rear drive shafts rotate at the same speed. This will occur regardless of traction or torque supplied to each axle. If instance if you are stuck (one wheel unweighted, 0 traction) it will transfer up to 100% of the available torque to the axle with traction.

As a side note, locked position is not intended for use in high traction road conditions, as it stands the potential to over load components, since it can generate torques in excess of that generated by the engine alone. To illustrate this take for instance a turn on pavement with it in the locked position. As the truck rounds the curve the rear takes a shorter path than the front so the rear starts trying to push the front, and the front equally tries to slow the rear. T0his will generate a positive drive torque in the rear and a negative drive in the front. Now if you accelerate at the same time the rear drive will see the full load of the engine in addition to the torque generated by the path differential of the two axles, therefore the rear sees more than 100% of engine/transmission delivered torque. So locked when off-road or in lower traction conditions, but unlock when you get backed to pavement or high traction conditions.
 

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Discussion Starter #3
The transfer case lever for the LT230 has the Lo-N-Hi like your 91 but also has a side movement to LOCK the center Dif. In the LOCKED position it manually locks the center Dif so that the front and rear drive shafts rotate at the same speed. This will occur regardless of traction or torque supplied to each axle. If instance if you are stuck (one wheel unweighted, 0 traction) it will transfer up to 100% of the available torque to the axle with traction.
Thank you so much! This was the missing piece of information I was looking for.

I kept reading about how the LT230 is locked but was combatting that with my own experience that it is not. Funny how in quite a few posting I read about the locking feature I didnt see anything about the side shift motion mentioned. Perhaps its just known. Or perhaps if I had a shift knob it would show an illustration. Can it be locked in hight and low or just low? Basically, what is the shifter motion I should be looking for?

Time to pull apart the center console and figure out what is up with the broken shifter. As of now it just flops forward and back like a wet noodle.
 

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CDL (center dif lock) is available in Hi or Low. transfer case lever to the left wil lock the center dif. lever to the right will unlock the center dif. when locked you should have an instrument cluster light iluminate that indicates that the CDL is locked.
 

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Discussion Starter #5
Got it. Thanks! I spent some time this evening on the lever. Got the broken linkage welded up and now have a first hand understanding on how it works. Doing some wheeling this weekend, So we'll see how well it goes now that I have the low range and center lock working properly.
 
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