Diff lock disaster - help please!

Diff lock on my '95 300Tdi has been erratic for a long while and has frequently needed to be reversed to "unwind" it. However, today, the light flickered on while on the road (having just been off road in diff lock), and before I could find a safe spot to stop and reverse up, there was an almighty bang, clunk and then no drive power.

A look underneath revealed a sheared UJ at the point where the front drive shaft joins the transfer box (the half of the UJ on the box side).

I've managed to recover the landrover home, but now what to do?

Is the effect of diff failure in the transfer box (so meaning a new transfer box and, of course at least one UJ) or does it get worse than that and mean problems at the differentials on the front and/or rear axles. My gut feeling is that the transfer box must have locked up which is why the UJ sheared, but without taking it all apart I don't know for sure.

Anyone who can suggest where to start looking and, if as I suspect a new transfer box is required, a source for a recon box, would be really appreciated.

Thanks.

a bust diff wouldnt break uj ,stuck in diff lock would ,put in diff lock and try it if it goes allright not t/box,bust diff usually requires fresh box , jack one front wheel up ,remove tunnel and operate diff lock while rotating prop,and feel operation using 13mm spanner on nut where selector lever goes into box ,switch screwed into far is often culprit for poor operation of diff lock collar ,and detent behind switch 6mm allen screw can be slackened if detent too tight ,but usually hi/low lever adjusted poorly so only just pulling out or in

Sorry - way beyond my knowledge

James will respond shortly I'm sure! PM him if not (jamesmartin) - top guy when it comes to mechanics and especially gear boxes

jamesmartin said:

a bust diff wouldnt break uj ,stuck in diff lock would ,put in diff lock and try it if it goes allright not t/box,bust diff usually requires fresh box , jack one front wheel up ,remove tunnel and operate diff lock while rotating prop,and feel operation using 13mm spanner on nut where selector lever goes into box ,switch screwed into far is often culprit for poor operation of diff lock collar ,and detent behind switch 6mm allen screw can be slackened if detent too tight ,but usually hi/low lever adjusted poorly so only just pulling out or in

Click to expand...

James, thanks for v prompt reply.

I've had another look at it while still on the trailer. It DOES go while the diff lock selector is engaged, in either H or L, in forwards and reverse. (This is obviously on in RWD as the front driveshaft UJ has snapped). It does NOT go when the diff lock lever is over to the right, it the lever clearly clicks out and the red light goes out. BUT it does go if the lever is over to the right but the red light remains on.

Are you saying that if what I've described is the case that the diff lock engagement might just need adjustment plus of course replacing the front UJ?

diff sounds all right new uj needed,diff lock is sliding collar that slides over front output shaft joining the two together giving lock ,it is operated by selector that is pushed pulled by spring so no direct contact to lever if stuck lever would just compress spring without moving collar this is to allow selection while moving in that you preload spring which puts it in out as shaft and diff align,as i said detent or switch can be screwed in too far making it harder for spring to push selector,when setting detent you wind in as far as inhibits mechanism moving with 13mm spanner on nut and wind out till good movement with obvious detent but not binding,lever in cab needs setting so that it will move difflock in out equally as lever through spring has to go past point of just selecting like you can with hi/low lever which is direct link

Thanks.

I slid the broken UJ off when I was winching the vehicle onto the trailer (it was flailing around), but didn't mark it for replacement so I'm not sure it will be balanced when I replace it.

With this in mind would be better just to replace the prop shaft with a new item which will be balanced and aligned (and also overcome any problems that may have arisen through shock to the prop shaft when the UJ broke)?

...when I say the UJ is broken what I actually mean is the flanged yoke on the transfer box side has sheared. Is this available as a separate part or do I need the complete prop shaft (irrespective of the balancing concern mentioned above)?

unless prop has come apart from splines there are no aligment issues as where it bolts to transfer box or diff makes no difference at all ,as default all props should be like double open ended spanner with both yokes nearest tube in same plane,lr do put them out on some front props 1 or 2 splines at most but will run in same plane perfectly well

so...final question to confirm, if the flange is broken do I need new prop shaft or can I obtain just one (splined) flange end with uj?

new prop tvb100610

Not quite the disaster I thought it might have been. Brilliant advice. Thanks again.

no problem, but i know plenty of garages that would have fitted new t/box etc