The mechanic said he was going to use something with GL-4 per your advise because of brass, on the first page it was suggested to use Castrol Manual Vmx 80w due to the same symptoms I may go this route although it is 80w
A manual transmission fluid of advanced design especially developed to provide easier gear changes over a wide temperature range.
It is particularly versatile in cold weather as it reduces shift effort at start-up, as well as controlling transmission noise and idle rattle at operating temperatures.
It should be used in manual transmissions of most car and light commercial vehicles (LCV’s) requiring GL-4 performance, where improved low temperature shift performance is required.
Features & Benefits
Quieter transmission operation and easier low temperature gear shifting improves driving experience
Improved gear tooth and bearing durability reduces the risk of breakdown and extended component life
Effective lubrication over a wide temperature range
It can be used as a low drag gearbox oil in 2-stroke motorcycles with separate gearboxes
SAE 80W viscosity – SAE 75W-80 extrapolated (equivalent to 10W-30)
API Service Classification GL-4