240 M46 into 740

SLT16

Hi all,

Just thinking of putting an M46 into my 740.

Will a 240 M46 fit into a 740?

I know the shifter location is slightly different, but i've got a shifter extension from a 740, so if i put it on the 240 gearbox will that fit?

Both cars are LH2.2 and B230F so no fitment issues except for the shifter.

SLT16

bump

DCW242

It will fit no problem, depending on which type of 740 M46 mount you're using you might need to swap the mount brakcet on the gearbox, if you're using the early system the 240 mount should work.

carnut222

The propshaft will need to match the transmission as well. 240 M46 prop will be too short for a 740 IIRC.

SLT16

carnut222
The propshaft will need to match the transmission as well. 240 M46 prop will be too short for a 740 IIRC.

Is the propshaft on the 240 longer than on the 740? I have a 240 manual propshaft that was on an M46 car.

If its longer than the one on the 740, cutting it down should be quite cheap and easy.

Not sure if lengthening it is possible though...

SLT16

Also, what's IIRC?

Spac

If I Recall Correctly.

Roinik

A front shaft off a 240 with BW55 or M45 would allow easy cutting and shutting.

SLT16

The shaft i have is from an 87 240 with an M46. I am wondering if it will easily be able to be cut down for a 740?

Also, are shafts from M46s and 47s identical?

Roinik

Not by a long shot. The M46 box is a Bahco-Volvo box with a Laycock overdrive bolted on. The front shaft is short and has 2 uni joints. The M47 is a shorter Getrag unit that has a longer front shaft. The shaft is fitted with a flexible rubber coupling instead of a uni joint.

carnut222

the 240 M46 front shaft will be shorter than the 740 M46 front shaft, as the 740 engine is about 100 mm farther forward than the 240 engine IIRC (as somebody else clarified already - mean if I recall correctly) Don't you just love the internet slang? :) I think the M47 shaft would be longer than an M46 shaft, as the M46 transmission is longer than the M47 transmission. When I was trying to find the correct front shaft for the M45 I used in our 240 EV collection, I was shocked at how many different shaft lengths there are just for 240s! Plus, there are different shaft diameters and flange sizes, and then the later rubber coupling at the front. If you add in the 7-series to that mix you can have many more combinations! I was sorting thru a couple 55 gallon drums at Voldat looking or one the correct length...took an hour but I think I finally found one!

SLT16

I just got an M47 today from a 240.

I was aware that the shifter length was different, so i actually managed to get a shifter cage for a 740 for the m47 which is slightly extended, so it will fit fine and dandy.

Got the correct flywheel.

740 clutch master,

Mounts and crossmembers.

Clutch line.

Now all i am looking is for a driveshaft that will fit.

If anyone has it, i'd be more than happy to get it and pay for transport.

carnut222

Good going! I have a 740 M46 driveshaft but that will be too short, plus I may need to chop it to use in my 240 manual conversion if I can't find a 240 M46 one...or if I want to use the rubber donut connection.

There may be some down this way (try Berry Motor Group or Voldat) but postage wouldn't be cheap.

SLT16

By the sound of it, m47 740s seem so rare.

ramrod

I had no idea the M47 was made by getrag

carnut222

ramrod
I had no idea the M47 was made by getrag

I don't think it was. @Roinik may be getting confused with the 5-speed that was put in a few V6 260s in the early days. That was a Getrag. IIRC the M47 was a modification of the M45/6 design with an added 5th gear set on the back.

SLT16

How much would I be looking to possibly re manufacture the m46 shaft I have to fit my 740?

carnut222

Some good info here on ratios:

https://people.physics.anu.edu.au/~amh110/gearbox_ratios_compared.htm

The Getrag box in the 260 series was called the M51 FWIW (for what it's worth) ;)

Roinik

Thanks Greg. I'll be pulling one out of a LH2.4 89 240 at some stage this year, so I'll see what I find.

carnut222

Here's an M47 exploded view. As you can see the front bit is similar to M45/6...the 5th gear is basically an add-on at the back.