240 General: New member + '82 244 transmission swap advice needed

[Clan]

Originally Posted by mylittletony

The M46 is easier to find with the speedo drive needed for your instruments. The M47 (pure 5 speed, not 4+OD) was introduced a few months before the cars went to an electronic speedo with signal coming from the rear axle.

You CAN find a cable output M47 but they're much, much rarer then those without.

You could change the rear axle and fit an M47, but it's a lot of hassle if you don't need to. Coming from someone who did that and converted my speedo, I wouldn't do it again!

Make sure you get at least the front section of the prop to suit whatever gearbox you go with, they're all different lengths.

The overdrive can be easily wired in on a standalone circuit, but you must remember to disengage it, treat it like a switch for 5th gear.

there is a cut out switch on the gearbox which turns the OD relay off when you drop out of 4th gear . The circuit is quite simple so best wire it as it should be . See if you can find a stalk switch to activate from the steering wheel without taking your hands off the wheel ...

Volvo's usual practice is when you have ab OD the axle ratio is lower , hence the whole car feels more lively . I converted a 140 once and it had the standard axle ratio , it made the OD gear rather lifeless , ie ok down hill and on the flat but any slope and the gearing was a bit high, but you can always drop back to 4th gear :-)

[EJRB]

Thanks all for invaluable help, already learnt a lot in the short time I have been here.. I was thinking that the m46 was the way but if the m47 on offer has the prop etc in place it may be a good idea..

Do factory fitted od boxes have the switch in the gearstick? If anyone has an od m46 with accoutrements I would be very interested as well..

[Clan]

Originally Posted by EJRB

Thanks all for invaluable help, already learnt a lot in the short time I have been here.. I was thinking that the m46 was the way but if the m47 on offer has the prop etc in place it may be a good idea..

Do factory fitted od boxes have the switch in the gearstick? If anyone has an od m46 with accoutrements I would be very interested as well..

Yes a slide switch , but much easier to use if you can get a small stalk switch to mount on the steering column housing behind the steering wheel . The 140 series had this and was a delight to use , fingertip actuation . the M46 is a very heavy cast iron gearbox the M47 is all alloy but the same design .

[Clifford Pope]

In general with overdrives I prefer the switch on the gearlever because then you can coordinate operation with the gear changes. But as the Volvo one operates only in 4th gear (unless you modify the cut-out switches) there's not much point.
I once had a 240 with the OD switch mounted in the redundant square panel in the dashboard, close to the dip switch.

[Martin Cox]

I vaguely remember reading somewhere that Volvo chose to make overdrive only available on 4th gear to limit the amount of torque the overdrive unit had to handle. How true this is I don't know.

However more importantly it ensures there is no possibility of the overdrive being engaged when reverse is selected which could be catastrophic. It's something to be aware of if you make up your own circuit to operate an overdrive.

Martin

[classicswede]

Correct it is to limit the torque and never use in reverse

I used to wire them to use in any gear but in all honesty you only really need it in top. It could just be handy sometimes in 3rd when overtaking to use the OD rather than change up