Problem Diagnosis: Ringing Sound when driving

[NC Rover]

So when I start driving the rover, I get this loud ringing/clanging noise as if a big thin aluminum washer was tumbling and banging around in a dryer.

Brief Vehicle History:
-LT77 5-speed Transmission / LT230 Transfer Case (Full time 4 wheel drive ...low/high without diff locked....low/high with diff locked) / D90 axles

At first I discovered the mud shield on the front output shaft (where it connects to the transfer case) was loose and produced the same sound. I fixed that hoping the sound would be gone. Nope. Its back. I'm thinking its something inside the transfer case itself.

Any ideas on what this noise could be? All gears shift smoothly...no grinding. It will go into low/high with and without the differential locked fine with no problems. I have no performance issues with the vehicle...its just that the noise is so annoying!

Any suggestions would be great! thanks!

Below are pics of the transfer case as well as the front output shaft mud shield that was loose and is no tight. I thought that was the noise issue but its not...

[daveb]

did you try alternately removing the front and rear propshafts to see if that made the noise go away?

did you notice that your gearbox is cracked next to the drain plug where it bolts to the transfer box?

[49coe]

Something in the Parking brake? Just a guess.

[griswald]

Problem Diagnosis: Ringing sound when driving

My top pick is you have a bad U-joint in one of your drivelines...

When I ordered the replacement (I had high pitched squeaking and ringing too) the gent told me it is from the needle bearings running dry.

Jack up your rover and try to see if you have slack in the u joints, and also lube them if possible...

I would also consider dropping the front (and driving with the back) or dropping the back and driving with the front...short, distance only of course.

Hope this helps!

[NC Rover]

Yes we tried removing both prop shafts...the sound did not go away. It sounds just like a then aluminum washer jingling around in a metal box. I'm gonna have to take out the panel under the middle seat and drive with it open to see if I can diagnose the area where the soudn is coming from...

And yes I did notice the gear box was cracked. Its been like that for quite some time now with no problems or leaks.

I just replaced the rear output shaft seal as well as the ebrake shoes....ebrake works great...sound is still there.

[daveb]

reminds me...I once had a similar problem in my 59 SII. It finally stopped when the speedo cable broke. Try pulling the speedo cable and see what happens.

Yes we tried removing both prop shafts...the sound did not go away. It sounds just like a then aluminum washer jingling around in a metal box. I'm gonna have to take out the panel under the middle seat and drive with it open to see if I can diagnose the area where the soudn is coming from...

And yes I did notice the gear box was cracked. Its been like that for quite some time now with no problems or leaks.

I just replaced the rear output shaft seal as well as the ebrake shoes....ebrake works great...sound is still there.

[sven]

Maybe drain the TC or gearbox and see of any bits fall out. You could also remove that rectangular shaped cover on the TC and inspect as well.

[s3landy]

I had a similar but possibley different problem with my Defender with an LT77. Every once in a while it sounded like someone was throwing a handful of gravel under the truck.It shifted good and everything but I finally took it apart. It turned out to be two broken brass bushings that the throwout bearing rides on. Someone had replaced the parts at one time and left the old broken pieces in the bell housing. They were getting thrown into the flyweel.

Just a thought....

Mike

[NC Rover]

Maybe drain the TC or gearbox and see of any bits fall out. You could also remove that rectangular shaped cover on the TC and inspect as well.

If I remove the rectangular cover on the TC....will I need to replace any kind of seal or the bolts? I may give this a try.

We drained the TC and no bits of metal showed up.

I might try unhooking the speedo cable just to see if it does anything.

thanks for the suggestions!

[NC Rover]

I had a similar but possibley different problem with my Defender with an LT77. Every once in a while it sounded like someone was throwing a handful of gravel under the truck.It shifted good and everything but I finally took it apart. It turned out to be two broken brass bushings that the throwout bearing rides on. Someone had replaced the parts at one time and left the old broken pieces in the bell housing. They were getting thrown into the flyweel.

Just a thought....

Mike

This very well may be the issue. Because the sound is never repetitive...its random....like a piece of metal bouncing around against the flywheel. Hmm.

The sound is almost just like the sound of a christmas jingle bell. Crazy. I will try all of these suggestions. Thanks!

[sven]

If I remove the rectangular cover on the TC....will I need to replace any kind of seal or the bolts? I may give this a try.

There is a gaset from the factory, but you could scrape it off any use black RTV instead. RTV would actually seal better. You re-use the bolts.

[s3landy]

If you want to see if it is indeed a piece bouncing against the flywheel, hit the brakes hard and let whatever may be in there fall forward.

Mike

[NC Rover]

If you want to see if it is indeed a piece bouncing against the flywheel, hit the brakes hard and let whatever may be in there fall forward.

Mike

I attempted this with no luck. The sound only starts up once you get fast enough to shift into 3rd (I have a 5speed). And once its jingling around...you can take it out of gear and leave it in neutral, and it continues to make the noise until you slow down and it quits. The sound seems to be coming straight from under the middle and passenger seat...near the transfer case rather than hear the bell housing of the tranny.

I think I'll take the cover off the T-case and see what I can find.