question Diamond 'T' 980 Transfer box

I thought it would be interesting to post a small problem we have to see if others have come across this with their Diamonds and in the two types of transfer box i have come across, to which in the manual i only seem to see one type!

So last week whilst maneuvering in reverse the 980 decided to throw the main shaft forwards and punch the end out of the bearing cap !! thank goodness this did not happen on the road at speed.

From investigation the bearing is held in on the outer race by the bearing cap and the inner race by a circular nut, that nut has no means of being withheld, not castellated nor a lock tab, but wound up tight, but not in the case of ours as the nut had come undone wound its way back to the bearing cap plate and with a little movement on the shaft cracked the cap plate off in the centre.

Thinking we had another transfer box to replace the plate was a foolish thought at that has a different style plate and bearing set up as the photo attached shows.

So we are having the plate repaired, and the nut will be reinstated with locktight, fingers crossed this will be OK then.

Has anyone experienced a similar failure, or know of a safer way to hold in place a circular nut?

Tony Graves is kindly sending me some further technical information, but i thought as the old forum stretches further than my knowledge of DT owners, there would be nothing lost in asking.

I can't quite see how it works from the photos, but either stake it or drill and pin? Even a dab of weld if all else fails.

Andy

You may be able to fit a fastener across the bearing retainer to locate in the two recesses, then drill and fit sellock pin into shaft side of centre hole, while using the centre hole to tap out and thread for a suitable set screw, giving two anchor points. All the best Nigel, dt owner.

Thanks Nigel for your thoughts, are you the same Nigel we met at W&P ?

In plenty of discussion on this with retired heavy haulage users who worked these after demob, two have told me they had the early transfer boxes fail to full destruction when the slogging nut did what it did to us, probably why the later box was designed !

if your T is with the early transfer box with the cone cover as in my photo I would take a sneaky view to check it's tight, I did read this is a service item after 2000 miles

I have wound the nut back on with some quality thread lock compound, so fingers crossed.

Yes thats me, met at W and P show, was a good show, even with the mud that made things interesting for alot of the viewing public. I will take a look at mine as an early model T. Looking for a tail gate now. All the best with your projects, Nigel.