Citroen XM Forum

Hi Chris, no I haven't tried that, will investigate. It runs on 80W90 GL5, forget which brand is in there at present.

Cheers

Marc

Hi Marc,

A lot of boxes produced in the 70s/80s/early90s were listed as needing 80W90 or thereabouts. It turned out that for many vehicle makes, gear engagement when cold, and gear shifting, was notchy and difficult. ZF 5-speed boxes for Rover were notorious for this: on a cold day, even if you managed to engage 1st at standstill, you couldn't actually shift on the move from 1st to 2nd! Rover's original spec was 85W90. Realising the problem, dealers were asked to remove the gear oil and fill with ATF. Problem solved.

Many 'modern' close-tolerance sunchro' boxes suffered the same, and the lubricant manufacturers rose to the occasion with Manual Transmission Fluids. An early Castrol one was SMX, which looked just like red ATF. Castrol later added Syntrax to their range, and now it's called Syntrans, in several varieties.

Details here: http://www.castrol.com/en_gb/united-kin ... luids.html

These fluids approximate to 75W, but are optimised for gear engagement and changing. Best, these days, to keep away from 85...90 stuff, which belongs now almost to a past era.

I first used SMX MTF back in the 70s on a 5-speed ZF box conversion for my P6B, and have used MTF several times since - including BX, RAV4 and the 2.5.