Which Gearbox?????????

Scott Stephen · May 24th, 2006, 22:55

Hello all, I've just bought a 1975 244 Saloon in outstanding condition for her age. (£80 off ebay!!!!!!!) She has only covered 84000 mls from new. I couldnt believe my luck when I won her for so little.

I wish to change the 4 spd box for a 5 spd box as she is a bit revvy at motorway speeds. I am unsure what is compatible. The car is fitted with the B21A engine. I seem to recall that my old '86C 740 2.3 Carb used to rev extremely low at 70 but I cant remember the gearbox code. Any help/advice appreciated

Ben O Brien · May 24th, 2006, 23:27

An M47 5 speed is fitted to most of the later models, this should fit just fine though check that it has the same output flange for your original driveshaft or you'll end up changine the shafts too, not hard but more work. Hope this helps.

Regards
Ben

dgbalfour · May 25th, 2006, 08:13

You may also have an issue with speedometer cables - the early ones were cable driven from the gearbox, the later ones used a sensor mounted on the back axle.

It might be worth sourcing a 4spd + overdrive from another cable driven speedometer'd car.

David

Clifford Pope · May 25th, 2006, 08:30

Also watch for the number of splines on the gearbox input shaft. early 4-speed boxes were different. I think they are still interchangeable as long as you use the appropriate clutch plate.
Ideally you do need access to the donor car. With the M47 5 speed the prop shaft couplings and flanges are often different, and the M46 overdrive box has a shorter front section of shaft, because the box is now longer. Mounts also differ, but are interchangeable. The alternative set of captive nuts for putting the cross member in the other position should already be present.
If going for the M46 you would of course need the appropriate gearlever as well, also overdrive wiring and relay.

Mike_Brace · May 25th, 2006, 10:18

The boxes are interchangeable by changing clutch plate. Early boxes up to 79 had a coarse spine clutch and it went to fine spline after that. Cable speedos only went to about 1983 - after that they were electronic off rear axle. To use one of these you'd have to change speedo and rear axle - a lot of work. Clifford is spot on with all his comments.

Mike

May 24th, 2006, 22:55	#1
Scott Stephen Senior Member Last Online: Apr 2nd, 2012 10:32 Join Date: Nov 2001 Location: aberdeen View Photos By: Scott Stephen	Which Gearbox????????? Hello all, I've just bought a 1975 244 Saloon in outstanding condition for her age. (£80 off ebay!!!!!!!) She has only covered 84000 mls from new. I couldnt believe my luck when I won her for so little. I wish to change the 4 spd box for a 5 spd box as she is a bit revvy at motorway speeds. I am unsure what is compatible. The car is fitted with the B21A engine. I seem to recall that my old '86C 740 2.3 Carb used to rev extremely low at 70 but I cant remember the gearbox code. Any help/advice appreciated

May 24th, 2006, 23:27	#2
Ben O Brien Senior Member Last Online: Nov 8th, 2023 18:22 Join Date: Dec 2002 Location: limerick	An M47 5 speed is fitted to most of the later models, this should fit just fine though check that it has the same output flange for your original driveshaft or you'll end up changine the shafts too, not hard but more work. Hope this helps. Regards Ben __________________ 82' 242 Cal Import, restoration beginning.. WTD: Rare 240/242 Parts, please pm if you have anything

May 25th, 2006, 10:18	#5
Mike_Brace Former contributor Last Online: Jul 2nd, 2022 07:54 Join Date: Dec 2004 Location: Rhosgoch, Anglesey	The boxes are interchangeable by changing clutch plate. Early boxes up to 79 had a coarse spine clutch and it went to fine spline after that. Cable speedos only went to about 1983 - after that they were electronic off rear axle. To use one of these you'd have to change speedo and rear axle - a lot of work. Clifford is spot on with all his comments. Mike __________________ A Volvo is for life not just for Christmas!

May 25th, 2006, 08:13	#3
dgbalfour VOC Member Last Online: Today 13:59 Join Date: Jan 2006 Location: Bedford	You may also have an issue with speedometer cables - the early ones were cable driven from the gearbox, the later ones used a sensor mounted on the back axle. It might be worth sourcing a 4spd + overdrive from another cable driven speedometer'd car. David

May 25th, 2006, 08:30	#4
Clifford Pope Not an expert but ... Last Online: Apr 26th, 2024 12:45 Join Date: Dec 2001 Location: Boncath	Also watch for the number of splines on the gearbox input shaft. early 4-speed boxes were different. I think they are still interchangeable as long as you use the appropriate clutch plate. Ideally you do need access to the donor car. With the M47 5 speed the prop shaft couplings and flanges are often different, and the M46 overdrive box has a shorter front section of shaft, because the box is now longer. Mounts also differ, but are interchangeable. The alternative set of captive nuts for putting the cross member in the other position should already be present. If going for the M46 you would of course need the appropriate gearlever as well, also overdrive wiring and relay.

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