what the best way to change the gearbox ratio, i have a 4.1 now and i'm changing to 3.44, but i have to change the inner gear, how hard is it to do while the gearbox is connected to the engine. i have just finished my gearbox rebuild for my other engine , so i know how to change the inner gear while the engine and gearbox apart, but i'm not wanting to do that.
thanks

Ubolt the diff housing & remove diff, unbolt the speedo drive housing to gain access to the pinion gear, undo pinion gear (good luck) refit new pinion gear, tighten up ^&*%$# tight, change over diff pinion & re fit, not a hard job to do if uyou have the right tools.

Doogie

_________________
I won Hay once, here's the pic to prove it..


Hay, it's not about the car, it's not about the venue, it's about the people that come here. Peter Dwyer, Mayor of Hay NSW.

thanks

i should be right, i'm a diesel marine mechanic. so i will have all the tools. will i need to engauge both gears to undo the pinion nut.

Thats how you do it.

Doogie

_________________
I won Hay once, here's the pic to prove it..


Hay, it's not about the car, it's not about the venue, it's about the people that come here. Peter Dwyer, Mayor of Hay NSW.

That should be an interesting exercise with engine on and selectors not disengaged.

Let us know how you get on.

_________________
1967 Cooper S - new front bearings to do.
1965 Cooper S shell - Slow progress. No time or money!
1966 Deluxe- next rustoration!
Mk 2 & XJ6 Jags. Less said the better.

i will be doing it next week. has anyone done this before.

Use first and fourth gear, the ratios between 2 and 3 may not hold the 200 foot pound (or whatever the pinion nut is) of torque.

I have done it with a remote shift box, it's easy (just remove the selector interlock), but not so with a rodchange.
They will be harder to move the selector forks as the only access to them with engine on is through the back, once the selector spool is turned anti-clockwise to disengage it.

Lock into 1st and 4th gears, with either type box. This minimises the stress on the gear teeth.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

would the gears be able to take a rattle gun or use a braker bar be more gentle on the teeth. i'm just thinking about the teeth ripping off.

To do any job properly, a fastener should never be tightened with a rattle gun.
The breaker bar would be far safer on the gearbox.

Ive used rattle gun to undo them but not doing them up..I use a bar for that one..

Agreed, never use them to do the pinion up, it's too easy to bust expensive bits...
Some rattle guns are good for 450lb/ft or more.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I broke 2nd gear and the cluster trying to undo one with a breaker bar with 3rd and 2nd engaged

_________________
did I tell you that I won a trophy?

It`s easy to do in either box,,, as the good Doc says the extension housing (remote) type box you can take out the interlock swing plate mech from the speedo drive housing area & the gear shift actuation rod out of the case & select the gears manually into 1st & 4th...

Rod change type box needs to spin the interspool lock rod out anti clockwise from where it sits within the selector fingers & then manually select 1st & 4th via the use of a thin screw driver & push the middle fork finger thing into 4th gear & lever back the top fork finger thing into 1st gear ( all very technical terms i know:-) )

& i`ve used a rattle gun to rip the pinion nut off before, but best to use a BF breaker bar & stand on the dam thing till you hear/feel that "Click-Click" of your pretend torque wrench & the appropriate tension to do it back up

It`s not really that hard,,,, BUT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! on the rod change type box-->Just remember to make sure you have the interspool lock rod back into the right spot within the selctor fingers PROPERLY before you fit the diff housing back on & do it all up... if it slips out or wasn`t put back in properly before then,,, well,,, you`ll only have to rip the diff housing back off again to correct it & yeah ok, i`ve done that myself a few times years ago so that`s why i know this sh!t,,, just take heed or you`ll kick yourself.

_________________
No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.