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possible to replace 5 speed gearbox with 6 speed?
- Thread starter skreamz
- Start date
I've also been told better fuel economy on motorways. and well... because i want one 
billygilly
Active member
which models came with a 5 speed??
Think you may have hit the nail on the head skreamz; doubt anybody here has done that particular mod, mainy because they've bought a 5 or 6 speed for a reason - economy, insurance, personal pref etc. Logically you'd think you could swap out the box but as SR says, you'd also probably be looking at replacing the diff too so the ratios weren't all mashed up.
Bolt pattern of the bell housing would be your least worry. You'd need to check input shaft splines, ecu settings, matching of engine torque to box ratios, final drive, etc. All are to a a large extent matched as a set.
You could end up with a near impossible to drive car, lower economy, poor performance and a big headache.
I've spent too much time swapping engines, gearboxes, transfer cases and diff ratios on Jeeps to believe it can ever be simple.
You could end up with a near impossible to drive car, lower economy, poor performance and a big headache.
I've spent too much time swapping engines, gearboxes, transfer cases and diff ratios on Jeeps to believe it can ever be simple.
While I on the other hand have swapped gearboxes on Saab 900s and the Passat with no bother.
Saab were generic and the engine codes on the 20v VW had to match but that was all you needed.
Both FWD so the diff is inbuilt which may have some bearing (arf arf)
I understand the mpg obsession and the general joy of mucking around with spanners, don't give up yet.
Saab were generic and the engine codes on the 20v VW had to match but that was all you needed.
Both FWD so the diff is inbuilt which may have some bearing (arf arf)
I understand the mpg obsession and the general joy of mucking around with spanners, don't give up yet.
Finisterre said:
I totally agree with you - the joy is spannering and making things work, however you need to go in eyes wide open and know what you're doing and expect there to be issues.
I've swapped old Mini gearboxes to different ratios from MG's in a morning.
My most complex of a straight 6 to a V8 required a new auto box, adaptor plate, to a new transfer case and then to get it all right a new rear diff. That of course needed a new front diff to match. Of course new prop shafts and lots of wiring and plumbing. Still, the joy of a 400+ hp Jeep that has exactly what I wanted in auto and 3 selector levers, 160:1 crawl ratio, etc. is an awesome feeling when it all worked.
I've done it on an E36 328. I stuck an M3 gearbox in there. A 330i with an m3 gearbox and a 330i with another 330i.
Gearbox ratios between both boxes are the same from gears 1 - 5 gear 6 is an overdrive gear, therefore you won't need a new diff.
To accomplish this swap you'll only need:
Gearbox
Props haft
Clutch to match the gearbox
Selector arm
This bodes the same for all BMW model where they have a 5 speed model and a 6 speed model with the same engine, since the bell housing patterns chane depending on the engine. Or the 2.5l will take the 6 speed off the 330. The ecu's do not need reprogramming since they all cater for the 6th gear.
You can use a short diff for better acceleration and your cruising speed won't suffer too much due to the overdrive gear.
Gearbox ratios between both boxes are the same from gears 1 - 5 gear 6 is an overdrive gear, therefore you won't need a new diff.
To accomplish this swap you'll only need:
Gearbox
Props haft
Clutch to match the gearbox
Selector arm
This bodes the same for all BMW model where they have a 5 speed model and a 6 speed model with the same engine, since the bell housing patterns chane depending on the engine. Or the 2.5l will take the 6 speed off the 330. The ecu's do not need reprogramming since they all cater for the 6th gear.
You can use a short diff for better acceleration and your cruising speed won't suffer too much due to the overdrive gear.