240
Although it does the job, my M46 is pretty worn so will be looking to replace it in the next few months or so.
My preference is for an M47 but M46 is also fine. However I want one that's in very good condition, as I want it to last the life of the car.
No hurry at all but I thought I'd see if there's anything out there.
Thanks
lasercowboy
What year is your 240 again? Is an M47 compatible with your injection system, or do you also need the flywheel to go with it?
Berry's had a couple of M47s in stock a few visits back - I can't remember the price, but it certainly wasn't unreasonable.
240
It's a 92 - I need the LH 2.4 flywheel for any manual gearbox, not just M47. (So I do already have that in there - as well as an M47-suitable clutch - so it'd be a straight swap).
I spoke to Mark at Berry's back in May and he didn't have any then...
Vee_Que
Your best bet is to get another one and have it rebuilt if you want it to last.
240
How much do you reckon a rebuild would cost? If it's expensive, I'd assume T5 would be a better option?
240
And can others confirm Vee Que's conclusion? Doesn't seem to make a lot of sense, surely there are some low km or looked after gearboxes out there... my car's not turbo or anything and I don't race it, so I wouldn't be putting a lot of pressure on the box.
Vee_Que
They are all over 25 years old is the main problem. there are rebuilt ones around. one of the ones I have supposedly is rebuilt, but they are turbo ones so I cannot garuntee it. All parts are available so I guess I could put new synchros in an na box i have if you're keen.
lasercowboy
As far as I can tell having done a bit of reading on this topic a while back, the bearings are easily replaced, but a new set of synchros will run you AU$1500-2000 for an M47. This puts it at the far end of realistic, cost-wise. Is that type of repair economical? Maybe, depending on the use and intended outcome.
If you want to up the power, an M47 is never going to be a good idea, and for that money, a T5 conversion is probably a more robust candidate.
I'm of the opinion that if you can find a good one that's not been abused, and you're running normal power, an M46 or M47 (if looked after) should last forever. The M47 in my old UK 240 had >400,000 kms on and was still sweet as anything and tight as a squirrel's chuff.
But Alex is right, in that putting another unknown transmission in could land you in the same spot you're in - how will you know if it's better than your current one until it's in the car (unless it's from a driveable donor)?
familyman
Wish I'd pushed for metalwork in high school. (Missed out by one place.) There are so many things I could have used those skills for in the years since. I'm not even sure... can someone that can operate a lathe make shafts, gears, and synchros? (I'm guessing OEM is only so expensive because they're from Volvo.) Yeah, I know - just find another working gearbox. ;-) Still, would be nice to have the skills, put a lump of metal on the lathe, even autocad it on computer first, then have a computeri$ed lathe knock out a dozen... [Sigh.]
240
At that price (for the synchros), it doesn't make sense to recondition an M46 or M47. Even though I probably won't be trying to increase power, in the near future at least, it seems more logical to go for a T5.
Regardless of that, I don't have the money at the moment, so finding a good used box is the only option.
I have a used M46 lined up which I'm told works fine, it is in a car at the moment but it's interstate so I can't drive it myself... this thread was just to see if I could find any other options to consider.
@lasercowboy your logic seems right - look after the box and it'll be fine. (I think my problem is that my current box wasn't looked after well enough.) Yes, they're 25 years old but sometimes that doesn't seem to matter with Volvos...
On the subject of gearboxes... I find 1st in my M46 to be way too short - I'm having to shift to second far before I'd like to as I hit about 3000rpm after about 2 or 3 seconds. Does the M46 and M47 have the same ratio on 1st? And is this normal? My car has a 3.73 diff, and I'm not sure if that's the ideal one for a manual.
The point being, is there any solution or do I just live with it?
Philia_Bear
354 or 331 make 1st usable
My prefrence on a 244 is a b230ft making ~165kw and a m47 with 331
This combo will last for pretty much ever and gets good fuel economy and takes advantage of the low end grunt of the setup
240
How hard is it to change the diff?
Can a 331 be found with a speedo sensor?
This always confuses me - is that better or worse economy than a 3.73?
(And slightly left field question... I have a B230FX - how hard to +T it?)
Vee_Que
Your car is perfect to turbo. Late motor, just needs an oil drain, move the amm, buy the turbo parts (not pre 1990 turbo manifold and turbo though!) probably only need ti chip the ecus you have even!
The t5 ratios are not much better than the m46 before shifting out of first, I don't know what your comparison is that doesn't need to shift out of 1st by 30kmh though. But the diff ratio you should have is 3.91 or so given you had an auto. What revs do you do at 100kmh in od?
A 3.31 will mean lower cruising revs, and better economy to a degree. But 940s gained taller diffs (4.1) and the economy improved, because you don't need to press the throttle as hard to get up to speed...
240
"just needs an oil drain" - that's the hard part, right?
Pretty sure the sticker on my diff says 3.73. Is it possible that it had a 73 instead as one of the later cars (with B230FX)? I think it had the AW71 too instead of 70 (not sure about this - the sticker on it said 71, but when I took the oil pan off it said 70) inside the box).
Anyway, I think I do around 2500rpm at 100 in OD, maybe a bit more. (Fuel economy is between 10 and 11/100 but obviously that depends on a lot more too.)
As my current M46 is worn, shifting from 1st to 2nd is a pain (requires a fair bit of force). With a good box, I suspect the ratio wouldn't bother me as much. (I realise that such a ratio is good for acceleration - but if I accelerate hard, it's harder & longer to change to 2nd so I just lose all my momentum.)
lasercowboy
Does it help to double-declutch from first to second? If so, it's likely the syncro that's worn. If not, the gears themselves, or bearings on 1st/2nd. Has the gearbox had decent oil put through it? If it's had the wrong oil in, that can make a massive difference on the 1st-2nd gear change.
240
To be honest, it's probably the gears and synchro.
Doesn't seem to help a lot if I double-declutch but to be honest I'm not great at that anyway.
It has got decent oil though. From memory, I used Redline ATF type F which was what everyone seemed to recommend on turbobricks.
Brehon47
240
I have a 4 speed M46 - J type overdrive; fine spline input. Complete with shifter...I removed it from a 240 sedan. The vehicle was in very good condition - until it was rear ended. It was a spare for a 242GT I was going to rally. Available for inspection at a mate's workshop in Granville. Happy to consider an offer - pick up preferred. Tiny
familyman
You guys know how IPD has/had a plate with a short rod to permanently engage the overdrive on an automatic... Is there something similar for an M46 that would negate the need for an M47 swap? Or does an M47 have a better fifth gear ratio?
I'm asking this on both 240's and my own behalf. Personally, I've been avoiding an M46 swap mainly based on this reasoning... thinking the M47 is 'better ratios' than an M46. i.e. Lower revs in 5th gear if I'm not describing that right.
240
M46 OD ratio compared with M47 5th gear:
http://people.physics.anu.edu.au/~amh110/gearbox_ratios_compared.htm
There is a minor difference.
However I haven't found there to be any problem at all with the ratio of the OD (I sit at 2500rpm at 100km/h which is quite reasonable).
Rather, the advantage of the M47 is that by avoiding the OD, you avoid the potential problems that the OD units normally bring.
Also, such a device as you described
@familyman wouldn't work with an M46 because there'd be no way to only use 4th gear (without OD)...
@Brehon47 thanks, I've sent you a PM.
familyman
Hm... Going by the chart, why don't people go for M90s as much as M47s?
I know it says to get one post-1995, and also says: "Biggest issue is the flywheel, you'll have to take the 850R clutch and a flat B21/23 flywheel and modify accordingly." (Whatever that means.) But if B230 engines are in both cars, why wouldn't people just swap the box, clutch, and bellhousing all at the same time - why take only the gearbox, meaning you now have to use a different flywheel, 850 clutch, which now means the tailshaft is too short?
Or did M90 boxes not make it to Australia?