I purchased a 2002 Discovery II SE7 for my sons first car. It has just about all the usual quarks the LR have or so my research suggest. There are two problems I need help with from someone that knows more about this then I do. I know the LR has been lifted a couple of inches with spacers and the rear driveshaft has been replaced with aftermarket. I believe the front has been too but I don't know (three ujoints). I will provide pictures in the attachment section.

First is the driveshaft. There is a vibration at 55+ MPH and I want to test to see if the front DS is the problem. The way I understand it is the 2002 doesn't have the CDL option so my question is can I still pull the driveshaft and drive without the ability to engage the CDL? I believe the front driveshaft has been replaced and I know the rear has, the rear doesn't have the rotoflex. The front DS looks like its got three brand new Ujoints from diff to Tcase. My son is driving me crazy to fix his first ride. How can I test the front shaft on the 2002?

Second is the AC only works on high and again research tells me it the resistor that has gone bad, I've not actually been able to find where its actually located or what it looks like on the passenger side but I have a good idea but I understand it also has a Final stage resistor and I don't know the difference. I've seen that some people have soldered the resistor off and the new one back on for the fix. I would like to do this option but need some more detail to do it since its a lot cheaper to fix it then replace it.

 

there is no way to drive your 02, unfortunately.
you can always inspect the shaft and have it re-balanced at a local machine shop if you feel that is the problem.
it hard to tell from that picture but just the color makes me think it was replaced, doesn't mean the replace was balanced correctly.
the resister is inside the duct work, the plug is just after the blower motor and the resister comes out threw the hole were the plug mounts.
I have a spare blower housing at home with a resister ill take a pic for you later today if you wish.

 

Yes the pics would be helpful.

The driveshaft looks like someone replace all three ujoints with greasable duralast ujoints. Since the vibrations isn't until 55+ MPH im just not sure if its front or back shaft. There is no way to electronically switch the CDL option or a better way to determine which shaft is the problem?

 

unless someone has added a CDL or replaced the transfer case with an earlier one, there is no way that i know of the lock it.

 

Just so I know it has to have both driveshaft to move. Meaning I cant remove the rear either?

Thanks for the resistor info. Do you know what type resistor I need to buy or where?

 

Yes, it must have both drive shafts to move. If you detect no play in either the front or back, it may well be something other than the drive shaft(s). It looks like it has factory alloy wheels. If not, it may be one or more of the wheels is not concentric with the hub. This would cause vibration, depending upon how severe, at the speed you note. It is fixed by using adapter rings which fill in the gap between the wheel center and hub. It may also be simple wheel imbalance.

Also have a look at the center coupling on the double cardan joint at the rear of the front prop shaft. It has a bearing where the two yokes meet and keeps both u joints on axis. If you can push the shaft up or down when the joints are in 6-12 o'clock position, it suggests the bearing is gone and will cause quite a shake. It may not have been replaced with the other joints.

 

That may be the most helpful thing I have seen so far. I didn't know this about that shaft. I will look into it today.

Another note I spoke with the original owner and he told me it didn't shake until he did the lift. It has a Toddco 2" spacer lift in the front and a 1.5 in the back. Once the lift was complete is when he noticed the vibration. He replaced the tires with brand new tires and then the rear prop shaft but the vibration was still there. This leads me to believe that the 2" lift is causing the vibration...maybe it wasn't noticeable until the two inch lift causing extra pinion angle to make it apparent?

 

Yes it could if the cardan joint is bad. The slightly increased pinion angle may be less responsible than the increased prop shaft angle, as the joint accelerates and slows at a greater rate than before.

I should add that traditional ujoint design has both output and pinion shafts as parallel as possible in order for the two joints to cancel out the cyclical acceleration. With the LR, the pinions are tilted up, and so two ujoints would have unequal speed. It is solved in back with the rubber coupling, and in front with the cardan joint, although positions are reversed.

 

Try getting up to the speed where you have the vibration and stick your head out the window and look at the wheels, maybe they are the cause.


Good luck

 

Hey,
I just watched a good tech video on rebuilding a disco driveshaft. He was saying that the traditional method of visual inspection and then physically checking it for play while still bolted on the drive line has no value unless it's just plain obvious. It can look good around the caps and sit firm but this doesn't always confirm that a U-J isn't frozen! You must detach the driveshafts and then check for rotation in the parts. It's the only way to be sure. He showed an example of this.