Play in differential

[Keith Clements]

I checked out the slack in the transmission and it is 30 mm measured on the wheel rim when holding the opposite wheel and in gear.

Is this excessive?

Note the mark on the tyre is not the one being measured but the two on the wheel rim.

[Keith Clements]

can you add to Jowett talk in answer to your question on back lash. Cheers John




My back lash experience.

It all started with that noisy axle that needed attention. The replacement came via David Morris ‘thank you David’ This was fitted with a new crown wheel and pinion. On checking, the pre-load was over torqued, back lash excessive but the tooth pattern was close to spot on. On stripping down an excessive gap was found over the diff trust washers of 40 thou. Parts 54260 and 54262.
Four new trust washers made of equal thickness to try and maintain the running fit of the diff. Diff gears lapped in to remove the high spots. Axle reassembled and fitted and has covered over 1000 miles, oil just changed using Castrol EP 90 which is still available. As the backlash has been reduced this is perhaps an opportunity to check the amount in comparison with Keith’s exercise. I took the measurement at the chalk mark on Keith’s photo the widest part of the tyre and at this point I measured 18 mm backlash approaching about half the measurement Keith recorded.

[Keith Clements]

Thanks John.
When I get the SA on the lift I will compare with the SC, but as I suspected the SC play is excessive.
Since the SC has large tyres fitted I measured on the wheel rim, which makes your figure even smaller and as you say half mine.

[Mike Allfrey]

There is a possibility that the pin (Item 880) is loose in the crown wheel carrier (Item 886). Items are from the Javelin/Jupiter Spare Parts Catalogue of 1952. This problem has arisen in farm tractors, particularly those with forward/reverse shuttle shift transmissions. We used to install new carriers and the pins. Have not tried boring and fitting bushings in the carrier.

We are still in lock-down, but the first six months of a two-week lock-down are the worst!

Keep well,

Mike A.