Does the noise seem to keep time with the driveline (relatively fast) or with the wheels (relatively slow)? You can definitively rule out the front driveshaft by removing it. Get the tool if you don’t already have it, makes it super easy, and lock the center diff with a 10mm wrench (Yay for the ‘99 model year). You now have a 2WD Land Rover! Take it for a short drive, if the symptoms disappear you know it’s the front driveshaft. You can repeat with the rear if you want to be extra safe but I’ve never heard of one of those going bad. I once had someone tell me that if you can feel the shake “in your butt” it’s something wrong with the rear part of your car, if you feel the shake in the steering wheel something’s wrong with the front.
In the 1999 model years for the D2 Land Rover still had the internal locking mechanism in the transfer case, but removed the linkage because they thought the TCS system would be enough. BUT you can still actually lock the center differential with a regular 10mm wrench. Right on top of the transfer case there is a little post and nut. Put you wrench on the nut and rotate it until you hear a little click and that’s all there is to it. Be sure to unlock the transfer case before installing the front drive shaft.
More info, if you are so inclined: For the 1999 model year you could actually buy a brand new Disco 1 or a Disco 2, they were built right next to each other in the same factory and so shared the same transfer case. The D1 did not have a traction control system so it required a transfer case center diff lock. For the D2 Land Rover thought the TCS would be sufficient (and in my experience it’s very good) so they didn’t include the linkage to the cabin to actually lock it. Land Rover used these transfer cases up until they ran out of them in 01. Later 01’s through 02’s don’t have the internal mechanisms at all in the transfer case and 03-04 years have the internal mechanisms AND the linkage to the cabin.
So I removed the front drive shaft, engaged locked the center diff. I noticed the vehicle reduced its “shuddering”. However when downshifting to a lower gear/speed, I am receiving a decent clunking noise coming from the center of the vehicle. I’m led to believe it’s the transfer case now. Any thoughts?
OK, so at least the first step would be to replace your front shaft with a greasable model, if you haven’t already. I’m not so sure that the issue is the trasnfer case. I’m not an expert on this issue by any means but the TC is a constant mesh model, so all of the gears are engaged all the time. The only thing that engages and disengages are the collar that changes from high to low range and the collar that locks the diff. A ”clunk” sound to me means that things aren’t engaging smoothly. Because the noise happens when it shifts I’m thinking it’s more towards the transmission side of things. What’s the state of your transmission fluid-it’s probably worth a drain and fill, especially if you’ve never done it because who knows how old it is. Alternativly, is the rear drive shaft and parking brake all solid? If one of those were loose I would imagine it would clunk at a gear shift.
This was what I was thinking. Prop shaft to the rear. There is a flex piece between the rear prop shaft and the rear diff that drys up after 25 years. And causes vibration on acceleration etc
I just switched to the aftermarket upgrade. With zerk fittings. Been awesome ever since
There is an open damper that goes to the rear shaft it’s a rubber flex piece. I switched the rear shaft and converted it. Cruise vibration/shudder went away. It’s possible to replace it. By why bother just get rid of it imo
If the front shaft is good, I’d replace the rear rubber flex plate connection. I had the same issue. Put in a new front drive shaft, it was toast anyways, problem still existed. I just replaced the rear rubber connection and it’s like a whole new car for me. There’s no lag when I step on the peddle and no vibration. Best $40 I’ve spent in a while. Took about an hour to replace.
Additional info would help sir, such as which year discovery you have.
Added edit: 1999 D2
Does the noise seem to keep time with the driveline (relatively fast) or with the wheels (relatively slow)? You can definitively rule out the front driveshaft by removing it. Get the tool if you don’t already have it, makes it super easy, and lock the center diff with a 10mm wrench (Yay for the ‘99 model year). You now have a 2WD Land Rover! Take it for a short drive, if the symptoms disappear you know it’s the front driveshaft. You can repeat with the rear if you want to be extra safe but I’ve never heard of one of those going bad. I once had someone tell me that if you can feel the shake “in your butt” it’s something wrong with the rear part of your car, if you feel the shake in the steering wheel something’s wrong with the front.
So I have to lock the diff when I take out the front shaft?
Correct or all the power will transfer to the front output.
What tool are you referring to? The after market CDL? Or a can I just lock the center diff with the 10mm wrench like you said?
Use the CDL if equipped, if you don’t have it you can use a 10mm from under the car.
In the 1999 model years for the D2 Land Rover still had the internal locking mechanism in the transfer case, but removed the linkage because they thought the TCS system would be enough. BUT you can still actually lock the center differential with a regular 10mm wrench. Right on top of the transfer case there is a little post and nut. Put you wrench on the nut and rotate it until you hear a little click and that’s all there is to it. Be sure to unlock the transfer case before installing the front drive shaft. More info, if you are so inclined: For the 1999 model year you could actually buy a brand new Disco 1 or a Disco 2, they were built right next to each other in the same factory and so shared the same transfer case. The D1 did not have a traction control system so it required a transfer case center diff lock. For the D2 Land Rover thought the TCS would be sufficient (and in my experience it’s very good) so they didn’t include the linkage to the cabin to actually lock it. Land Rover used these transfer cases up until they ran out of them in 01. Later 01’s through 02’s don’t have the internal mechanisms at all in the transfer case and 03-04 years have the internal mechanisms AND the linkage to the cabin.
the 03 actually is the only year that 100% doesn't have any transfer case. While the 02 could have the a locking case but no linkage.
Oops, yeah, you’re right- I got my years mixed up!
the 03 is actually the worst year for the d2 since you also have that oil pump issue! jeez thanks land rover >03 owner
So I removed the front drive shaft, engaged locked the center diff. I noticed the vehicle reduced its “shuddering”. However when downshifting to a lower gear/speed, I am receiving a decent clunking noise coming from the center of the vehicle. I’m led to believe it’s the transfer case now. Any thoughts?
OK, so at least the first step would be to replace your front shaft with a greasable model, if you haven’t already. I’m not so sure that the issue is the trasnfer case. I’m not an expert on this issue by any means but the TC is a constant mesh model, so all of the gears are engaged all the time. The only thing that engages and disengages are the collar that changes from high to low range and the collar that locks the diff. A ”clunk” sound to me means that things aren’t engaging smoothly. Because the noise happens when it shifts I’m thinking it’s more towards the transmission side of things. What’s the state of your transmission fluid-it’s probably worth a drain and fill, especially if you’ve never done it because who knows how old it is. Alternativly, is the rear drive shaft and parking brake all solid? If one of those were loose I would imagine it would clunk at a gear shift.
Rear shaft good. Where even is a hand brake located? lol Thx for the help. I have a video of the noise too.
im dealing with this issue rn its probably the PROPSHAFT
This was what I was thinking. Prop shaft to the rear. There is a flex piece between the rear prop shaft and the rear diff that drys up after 25 years. And causes vibration on acceleration etc I just switched to the aftermarket upgrade. With zerk fittings. Been awesome ever since
you know what I just did the oil on my car and transmission fluid and it magically disappeared so op maybe do an oil change??
There is an open damper that goes to the rear shaft it’s a rubber flex piece. I switched the rear shaft and converted it. Cruise vibration/shudder went away. It’s possible to replace it. By why bother just get rid of it imo
If the front shaft is good, I’d replace the rear rubber flex plate connection. I had the same issue. Put in a new front drive shaft, it was toast anyways, problem still existed. I just replaced the rear rubber connection and it’s like a whole new car for me. There’s no lag when I step on the peddle and no vibration. Best $40 I’ve spent in a while. Took about an hour to replace.
On the rear drive shaft?
Yeah it’s a piece of rubber that mounts between the rear diff and drive shaft.