1999 Discovery SD (series I)

Hey everyone,
Disco started vibrating heavily through the steering wheel becoming obvious at 30 mph and increases w/ more acceleration. Once I take my foot off the accelerator the vibration goes away completely.

I’m not able to reproduce the vibration with steering and steering does not make it worse or better
Braking is smooth and does not reproduce the vibration and the car is not pulling to one side to the other

I have a feeling it is either the front or rear drive shaft. From searching around it seems like it may be the rear drive shaft and more-so the fittings for the rear drive shaft.

Can anyone else confirm my thinking or has had the same issue?

Thanks

 

One way to isolate the front from the rear is to lock the center diff and take off one of the drive shafts. If the problem persists then replace that one and remove the other.

Do you have a rotoflex on your rear drive shaft or a universal joint?

 

Id start with driveshafts as well. When my u-joint was going up the play was visible from just trying to turn the driveshafts by hand with the car in park. For me it was the front driveshaft u-joint at the transfer-case (as that is common - exhaust heat burns out the grease).
this assumes U-joints not flex crap.

 

Thanks guys, I hope to get it up on jack stands tomorrow and will check out both drive shafts. I had bought parts for the front, but Atlantic British advised that on the series I the rear joints tend to fail so I ended up ordering parts for the rear, but will hopefully figure out tomorrow.

 

WaltNYC I thought the diff was permanently locked for the Series I?

 

nope. not at all. the center diff is 'open' until you move the lever inside the cabin to the left. When you do that, it locks the center diff and sends 50% of the power to the front drive shaft and 50% to the rear.

When it is open (lever in the cabin pushed to the right), power will flow to the end which is easiest to turn like any other open differential.

Locking the center diff means you will always have power flowing to at least two wheels. So if the front has no traction, you still have power to the rear (and hopefully some traction there).

 

Hey all,

Thanks for the help and suggestions.

I crawled under the Disco last night with the rear wheels on jack stands and grabbed onto the rear drive shaft while I watched the spider joint (U joint) linkage between the rear differential and the back portion of the rear drive shaft. The drive shaft moved independently from the differential linkage for about 8-10 degrees before engaging (yikes!). I ended up replacing the spider joint that night and all symptoms have ceased!

One last question though, I was sent a kit by Atlantic British for rear drive shaft in which a rubber flange was included that I didn’t see anywhere on my rear drive shaft... any ideas where this is supposed to be used? (Image below, sorry it’s so big)


Included in kit for rear drive shaft, but not seen on my discovery as a current part?

 

IIRC - prior to 98= roto flex (what you have pictured) --- - 98 and up - Ujoint
one or the other, but not both
sounds like a return to AB.

 

Ahhh, awesome thank you so much.