Greetings All,
i've been a long-time lurker here, and have gotten lots of great info about how to work on my '02 Disco over the years - it's all much appreciated.

Now i'm having an issue i haven't been able to find any specific answers to, so i figured i'd ask before i go spending a bunch of cash for parts i may not really need.

Issue:
While driving (not idling or even when pedal pushed while in neutral), there is a rhythmic "thump" which can be felt through the passenger floorboards, and after about 30-35 mph, can really be heard. The thump increases it's rate of occurrence as i increase my speed.

History and additional details:
i had the drive shaft replaced (with OEM) about 4-5 years ago, and probably have about 50K miles on it since it was replaced.
I have about 155K total miles on the truck.
Today i pulled off the front passenger wheel and had a good look around but did not see anything super apparent; but have to admit my "inspection" of the U joints on the drive shaft was pretty quick and un-thorough.
I've also been getting an occasional error code 734 (gear 4 ratio incorrect) over the last 4-6 months.
As far as driving habits, i'm pretty much a work commuter these days and haven't done any off-roading since the last drive shaft replacement.

Question:
So am i right to assume the U joints might be going, meaning another new drive shaft?
Tomorrow (probably) i'm going to change the differential fluids (front and rear since i'll be at it), and will probably even do the tranny fluid while i'm at it. Though i'm not expecting that to do anything in regards to the thump, it's just time...

Any thoughts on what could be causing the thump? Is it the drive shaft? Maybe the differential itself?

Thanks in advance for any advice!

 

STOP DRIVING IT.

I would say it's likely the driveshaft and you are very likely going to destroy the transmission in your truck if you keep driving it.

If my truck did that, I'd tow it home and it wouldn't move again til I'd pulled the shaft and inspected it.

You may not need a new shaft, the stock shaft can be rebuilt. I say "may not" need a shaft because I've been told the shaft can be damaged when the centering ball fails, which is likely what you are experiencing. This is one case where I would want it professionally rebuilt, and I'd triple check to be sure they replace the centering ball, which some shops don't do unless you tell them to.

New shafts are $350ish for an aftermarket, which is what you should get if your shaft is damaged.

 

Thanks Dr. Mordo.
The exploding drive shaft is exactly why it was replaced 4-5 years ago (and the tranny got rebuilt too...). But that time there was no signs of failure that were noticeable.

I would think 50K is a little on the low side for needing a new shaft, but had a feeling that's what it was... But again, i didn't want to drop $300+ on a new one (or 200+ having it rebuilt) until i got a little feedback from people who knew a little (or a lot) more than me.

Thanks.

 

I rebuilt the original driveshaft on my '04 around 41k miles. At 90k it started vibrating just as you are describing on a return trip from Tampa, Florida. Rebuilt the shaft, no problems since.

Not saying that is the cause of your vibrations. I am with Mordo though, it probably is. That code you got has been linked to several causes. See these: http://www.rangerovers.net/forum/7-r...ine-light.html); https://landroverforums.com/forum/di...174-p0734-783/.

My first rebuild only lasted around 50k miles... Just saying...

$100 in parts (3 u-joints and a centering ball) and you'll be back on the road. What part of the world are you in? There may be a forum member that will help with the rebuild for a beer or two...

 

I'm not certain rebuilding the drive shaft is something i'm too comfortable with... swapping it out is one thing, but what's the aptitude needed for rebuilding one? or more likely, what's more chance of messing it up and needing to get a new one in 6 months anyway?

 

Also, i read where at least one guy took the front drive shaft out and drove w/o it for a few weeks.
Granted, probably not the best idea, but better than risking exploding the tranny... How bad is doing that?

 

If you have a diff lock it isn't that bad. During my second rebuild it wasn't until I had the shaft apart that I realized RockAuto sent the wrong ujoints. I had to drive for a week or two with just the rear shaft. Take it easy on the throttle and you will be fine for a bit.

 

All I used were everyday tools and a vise as a press. A short piece of 1" bar stock or pipe helps when removing the caps. It's not a fun job, but is definitely doable for a patient person. The web has plenty of info on the procedure. Also, if you have a diff lock, go ahead and take the shaft off and give it a test ride. If the vibration goes away you have it figured out.

 

Thanks, and now this is going to sound really bad, but how do i know if i have a diff lock?

 

I am not sure whether the '02 has it or not. I know only some of the '01s got it so maybe it's the same for the '02. The '04s have them.

The easiest way to tell is if you high/low range selector **** moves to the left (should be indicated on the shift diagram as well). If that's not there, there will be a nipple (bolt) on top of the transfer case that needs to be turned.

See this thread... https://landroverforums.com/forum/di...ck-02-a-13274/