Gearbox Clutch CVs - Gearbox type swap

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HarryMann: T25s can have their 4 speed boxes swapped for 5-speed and vice versa. 

Selector rod layouts are the main gotcha. Diesels are slightly different rear selector rod detail; TD diesels have different front gate boxes (wider cooling tunnel)

yankiecamper: I've changed my old 4 speed diesel box for a 5 speed turbo diesel one ive removed all the four speed linkage and replaced it with the 5 speed linkage but now i cant get it to work its all really stuff and tight can i put a 5 speed box and linkage into my 1981 van or are the chassis different i.e. the holes that it all goes though.

any help would be gratefully received

metalmic8ey: Have you replaced ALL the linkage from g'box up to and including the gear stick and its mounting box?

yankiecamper: Yes I've changed the whole lot from box to gear stick its all just really tight I wondered if there was any diffrences under the vans on later models for the 5 speed selector rods?

dug: Just a thought, if i remember correctly the long rod has a dip to clear the cross member near the back, it could be you have this upside down and its rubbing... I may be wrong but im sure my mate had a similar problem.

SyncroG: The vans factory built as Turbo diesels have a different cab floor with extra large air duct for the rad fan, hence the gearstick houseing below the stick is different and mounts underneath the floor rather than in it (?) so the leaver is in the same place relative to your seat. Don't know what would happen if you fit a TD houseing on a non TD floor (asuming there are only the 2 different floor types, don't know if early stuff if different) but it probably won't work as it'll be in the wrong place - could be the route of the problem.

yankiecamper: Right peeps! I've done it on the 4-speed linkage there is an extra bracket which my 4 lb lump hammer removed last night! Now its all good, it's as free as a bird . Many thanks. NB. Extra bracket was making it bind..

Aiden: fyi - Please note the following info is for watercooled 1983 on, not necessarily the Aircooled/early diesel variants with the early gearbox, if you want to know about them look at Vagcom, Etka, Etos etc..

gearsticks and the associated "boxes" below gearstick come in these flavours,

4 speed Petrol and n/a diesel 4 speed Turbo diesel

5 speed Petrol and n/a diesel 5 speed Turbo diesel

Syncro Petrol Syncro Turbo diesel

front linkages come in these flavours

2wd 4 speed 2wd 5 speed Syncro

and rear linkages come in these flavours

2wd petrol 2wd diesel Syncro Petrol Syncro diesel

For the perfect gear change you want the four speed 2wd gearstick and front half of the linkage, the rear linkage you have should be right assuming the vehicle still has the original gearbox and engine type in it. You can stick with the 5 speed stick and linkage but you'll find getting reverse a bit of an 'a***' and 1st and 2nd won't be easy as the extra spring pressure in the 4 speed gearbox is working against the extra spring plunger at the bottom of the five speed gearstick, but it may be possible to adjust the thing to work and you'll get used to it, hey if you could cope with the original 5 speed set up..............

4 speed and syncro front linkages have two nylon tipped ears at the bottom of the gearstick which point upwards and interact with the 'gate' and the sides of the box under the gearstick

5 speed gearstick have two nylon tipped ears which point down and interact with the two alloy guides in the bottom of the box under the stick and there's a small metal bar on the front linkage which interacts with a plate on the side of the box to provide the reverse lockout and a sprung plunger on the bottom of the gearstick gives the extra positive spring pressure when you try to go to first (and reverse). Actually make that 'should' have nylon tips cos lots of them are fobarred hence Ian (Silverbullet on here) is making the repair kits at my behest (which can be obtained at Brickwerks) to help sort out the vague selection/poor gate experienced by many despite refurbishing the other bushes in the linkage and spending time setting it all up, only to discover it's barely any better.

To fit an Aircooled box you must change the rear linkage as that is completely different to a watercooled one.

Also see:

Sloppy gear change improving

Gearchange - Pictures and drawings