SASLess
I'm afraid I must rely on Rigga's recall (whom I know, and trust implicitly) when he said (above);
And, through an assumed lack of drawing control, transferred the same problem to Almondbank, UK.
Almondbank was (is) the 3rd line repair facility for Chinook transmissions, from about 1983-on. This doesn't mean they repaired or had even seen the transmission components from the 1989 aircraft. In common with many Chinook components tasked to NARO (Naval Aircraft Repair Organisation) - ignore "Naval", in this context it is all Rotary Wing - there was a complete lack of supporting documentation. On the face of it, one could criticise the London office responsible for ensuring the correct resources were in place before declaring a 3rd line capability, but one must also take into consideration the solid evidence that, as late as 1999, maintained technical publications, drawings and their configuration control were still absolutely verboten and largely unfunded. I can assure you from personal experience that when Chinook was being introduced to service any such tasking at 3rd line received little or no support and staff were told to DIY. Having to reverse engineer and develop your own test procedures was quite common. In some cases, no test rigs were provided (a repair is not complete until verified) and those supplied for other aircraft were adapted locally. This was also a complaint from the AAIB during their 1994 investigations into ZD576. The CHART report of Aug 1992 re-enforces all this.
Hope this helps.