Information on upgrading a gearbox

AngieMaggieB · Jun 26th, 2011, 01:07

Does anyone know if it is possible to upgrade (with relative ease) a 1980 245, four speed gearbox with a later five speed one.

Thanks,

Angie

Clan · Jun 26th, 2011, 09:19

yes its possible but the clutch and possibly flywheel will be different . so best get everything from the flywheel to the rear axle flange from the scrapped donor car ..

make sure the 5 speed box has a drive for the speedo cable though and make sure the rear axle ratio of the donor car is the same as yous or you will have to find the correct speedo drive gear to fit the new M47 5 speed gearbox to make the speedo read correctly .. You could get the axle too i guess :-)

brodgar · Jun 27th, 2011, 17:05

that speedo cable and unit is extremely important

clarification== the old car has a mechanical speedometer pick up( wire cable)
from the gearbox

== the donar car might have an electrical speedometer pick up
with an ELECTRIC wire and picks up the signal from the
backaxle. In the backaxle there is a pulse unit which you will
not find in the older car

conclusion --- if you want to do something like that buy the 245
and a good donor car - as you will need many parts from it

and -- when you are in such a project, change the engine as well for a 2.3 engine

redboy · Jun 27th, 2011, 18:16

In order to have the speedo drive in the right place, you need a 4+overdrive box not a 5 speed. This is a very simple bolt-in conversion- all you'll need is:
gearbox w/ overdrive
propshaft- as the new gearbox is longer
wiring for overdrive
gearshift
OD relay
The wiring connects just by a single lucar connector to the fusebox, and bullet connectors to the overdrive.

I'm in the process of converting my '79 245 from automatic to overdrive manual- yours will be much easier. You can use the same clutch between a 4 speed and an overdrive- they're cheap on ebay at the moment. I got mine for £20 for a Luk kit.

If you get all of the parts, its no worse than changing the clutch.

cheers,
Brian

redboy · Jun 27th, 2011, 18:17

Oh- and 4+Overdrive gearboxes were used until about 1984/5. The way to tell is that they have a little button on top of the shift lever with a '5' or 'on' written on it.

Its called the M-46 in Volvospeak.

Jun 26th, 2011, 01:07	#1
AngieMaggieB New Member Last Online: Oct 26th, 2017 21:42 Join Date: Jun 2011 Location: Bristol	Information on upgrading a gearbox Does anyone know if it is possible to upgrade (with relative ease) a 1980 245, four speed gearbox with a later five speed one. Thanks, Angie

Jun 26th, 2011, 09:19	#2
Clan Experienced Member Last Online: Yesterday 23:47 Join Date: Jun 2007 Location: L/H side	yes its possible but the clutch and possibly flywheel will be different . so best get everything from the flywheel to the rear axle flange from the scrapped donor car .. make sure the 5 speed box has a drive for the speedo cable though and make sure the rear axle ratio of the donor car is the same as yous or you will have to find the correct speedo drive gear to fit the new M47 5 speed gearbox to make the speedo read correctly .. You could get the axle too i guess :-) __________________ My comments are only based on my opinions and vast experience .

Jun 27th, 2011, 17:05	#3
brodgar I've Been Banned Last Online: Nov 27th, 2012 10:56 Join Date: Feb 2009 Location: Forest Row	===== that speedo cable and unit is extremely important clarification== the old car has a mechanical speedometer pick up( wire cable) from the gearbox == the donar car might have an electrical speedometer pick up with an ELECTRIC wire and picks up the signal from the backaxle. In the backaxle there is a pulse unit which you will not find in the older car conclusion --- if you want to do something like that buy the 245 and a good donor car - as you will need many parts from it and -- when you are in such a project, change the engine as well for a 2.3 engine

Jun 27th, 2011, 18:16	#4
redboy Master Member Last Online: Aug 9th, 2013 23:07 Join Date: Dec 2003 Location: hastings	In order to have the speedo drive in the right place, you need a 4+overdrive box not a 5 speed. This is a very simple bolt-in conversion- all you'll need is: gearbox w/ overdrive propshaft- as the new gearbox is longer wiring for overdrive gearshift OD relay The wiring connects just by a single lucar connector to the fusebox, and bullet connectors to the overdrive. I'm in the process of converting my '79 245 from automatic to overdrive manual- yours will be much easier. You can use the same clutch between a 4 speed and an overdrive- they're cheap on ebay at the moment. I got mine for £20 for a Luk kit. If you get all of the parts, its no worse than changing the clutch. cheers, Brian

Jun 27th, 2011, 18:17	#5
redboy Master Member Last Online: Aug 9th, 2013 23:07 Join Date: Dec 2003 Location: hastings	Oh- and 4+Overdrive gearboxes were used until about 1984/5. The way to tell is that they have a little button on top of the shift lever with a '5' or 'on' written on it. Its called the M-46 in Volvospeak.

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