1970s Rockwell-Standard 4x4 Differential

Sorry to bother you with more questions but I am hoping members may be able to provide some info or guide me to the relevant information in relation to the two differentials I have in my XF4.

See truck here - www.hcvc.com.au/forum/YaBB.pl?num=1437819583/0

Both the front and rear differentials are Rockwell-Standard. I have managed to extract the following information from the differential housings.

I presume the differential is a Rockwell 5200. Could the A4 A5 73 be the date stamp. Could 3 (or 5) 83 be the ratio? Not sure on the last code as I am not confident that I have read it correctly.

I cannot find anything on the internet about 5200 differentials.

Unfortunately, the Workshop manual does not refer to any particular model of Rockwell differential. The illustrations and photographs show the differentials with different, 'smoother' gusset-less housings. If the date of 1973 is correct, then this would suggest that both differential assemblies were replaced after the army trials.

I was thinking that these type of diffs may have been used in International Harvester trucks from the late 60s/early 70s.


Front Differential







Rear Differential

Tommy, Get a Wire Brush & give the end of the Pinion Shaft a Real good Clean. The part No. & Gear set info will be stamped there.