Lightweight gearbox on S3

Evening all.
I have a petrol S3 with a 901 Suffix A gearbox. Crunchy change between 3 and 4 and rather than having her off the road for weeks/months whilst I rebuild (Follow up question on this below) I’ve found a 951 Suffix D which, I believe, is from a military or possibly lightweight. Will this just bolt on as a straight replacement onto the old girl?

Has anyone partially rebuilt a gearbox to sort the synchro changing between 3 and 4? If so, is it a straight forward job?

Hi Busby, does this help
https://www.syncrogearboxes.com/2014/05/13/land-rover-series-3-gearbox-identification/

on my 84 diesel had a suffix D with a crunchy change
I bought a cheap suffix B to renovate so I could do a straight swap
Rebuilding was easy and fun and not many special tools reqd.
I then. Decided to rebuild the SUFF D box , it’s straightforward to check for worn components
Once on the bench it’s quick to strip down and get back together , I bought new synchro hub and springs , I think one had come off on mine

if it is just a missing spring it’s possible to replace in situ , you can google it , although possible it sounded difficult with the lack of access

Thanks Steve. That was my reference page for the gearbox ID. That was my plan too - rebuild the used box (with unknown history/miles and likely its own set of issues) in the garage.
Sounds like they are all interchangeable and a straight swap - I just wasn’t sure about the military/lightweight variants.

Busby77 said:

Thanks Steve. That was my reference page for the gearbox ID. That was my plan too - rebuild the used box (with unknown history/miles and likely its own set of issues) in the garage.
Sounds like they are all interchangeable and a straight swap - I just wasn’t sure about the military/lightweight variants.

Click to expand...

same box