m46 or m47

11-19-2002, 11:35 PM

First of all, i beleive that this post is worthy of the performance board. If not please move it.

From what i have read in the past, I understand that the m46 is stronger than the m47. How much HP can the m47 hold? Also, is the m47 the same length(same driveshafts) as the m46. Probably not b/c of the OD. Please help. Thanks.

11-20-2002, 02:44 AM

I've heard the M46 is the better option for higher HP engines. Case in point: They never put a M47 in a turbo charged model (to my knowledge).

According to a Volvo Technician I know, the M47 is a re-work of the M46 and when you "shift" to 5th gear, you are actually staying physically in 4th gear but moving the stick engages the O/D (instead of hitting the button).

So, the M47 is a considered among some circles as a "true" 5-speed, but I think it is actually a O/D based 5th gear.

I'd also like to know if anyone has additional info on the differences between the 2 trannies. Either way, M46 or M47......they'll be a heck of a lot more fun than a AW71!!!!

11-20-2002, 03:13 AM

no, they actually did put m-47's in turbos

Hank Scorpio · 11-20-2002, 04:00 AM

Well, Paul (volvula) has a m47 in his 245ti and he seems to think it's holding up fairly well, though I know he baby's it.

The m47 is much more a true 5 spd than you give it credit for. Just look at the cut-aways of both, oh ya and theres no external OD on that one!

No really, it has a whole other gear set built into the trany.

11-20-2002, 06:01 AM

There were euro versions of the 780 turbo B-230FTI & B-234FTI that had the M47 behind them... Too bad we Yanks get the short end of the stick...

The first gear on the M47 is much lower too........

Andrew

Hank Scorpio · 11-20-2002, 10:50 AM

Quote:

Originally Posted by 2 780s

There were euro versions of the 780 turbo B-230FTI & B-234FTI that had the M47 behind them... Too bad we Yanks get the short end of the stick...

The first gear on the M47 is much lower too........

Andrew

For once I think we actually got the better deal, because the m47's are far weaker, depending on how bad you thrash them, than a m46. Aren't the m47 all alloy cased?

Doug

11-20-2002, 02:52 PM

I stand corrected on the M46/M47 issue. Didn't realize they put them in 240 Turbos. Never seen a 240 Turbo with out an O/D button. Same with the 700 series.

Roguls · 11-20-2002, 03:22 PM

M47's were NEVER an option on 240T's, not even 740T's (at least not in North America). The fifth gear on the M47 is a true fifth gear, not just a different way of engaging the O/D. If you look at the two trannies side by side you'll see what I mean (the O/D is big and bulky).

Roguls
New York, USA

boondoggie · 11-20-2002, 03:44 PM

Quote:

Originally Posted by Roguls

M47's were NEVER an option on 240T's, not even 740T's (at least not in North America). The fifth gear on the M47 is a true fifth gear, not just a different way of engaging the O/D. If you look at the two trannies side by side you'll see what I mean (the O/D is big and bulky).

Roguls
New York, USA

Yes they did. In 1987, and again breifly in 1991. I've seen an 87.

Here's a (my) M47, BTW:
http://www.geocities.com/p_demeo_2000/M47.html As you can see, the first secton is almost identical to that of an M46.... (and is still basically "added on") It is no weaker than a alloy M46 from a 740...

JamesDean · 11-20-2002, 04:13 PM

one question... isnt both the M46 and M47 based on the same 4 speed design, with just an O/D or fifth gear put onto the back half of the housing? it says something like that in Bentley, but i just wanted to ask...
Jimmy

Volvo78GT · 11-20-2002, 04:22 PM

Yeah basically.

There's at least about 3 different designs for the 4speed part (1 steel and 2 alloy designs that I know of) and then, from what i've seen of the early 5 speeds, the 5th gear is just simply that, a gear stuck on the back of the 4 spd gear box... instead of the - supposedly - less reliable OD...

My OD runs real nice... its kinda nice to have a auto top gear... flick the OD off and its off. Because mine's nice and firm, its like having a clutchless gearbox... sweet.

However there's nothing that beats a true 5speed, or 6 speed for that matter. The M47's that I've seen are realy just 4 speeders that have a 5th gear on the back. From what I've seen I'm not that surprised that they had poor oiling for the 5th but whadda I know?

For a NA application up to 200hp I'd say, a M47 is nice (make sure its properly filled eh?) and a NA or Turbo app up to 225-250hp a M46 that's in good shape will serve perfectly well. I personally think that the Supra or Celica tranny is quite sweet.

I dont understand a comment that was made earlier... about having a even shorter 1rst gear to make your car faster... I ask why???? Volvo 1rst gears are so annoyingly short!! Just tweak 2nd gear down a bit and you'd have a much better 1rst gear in my opinion... now if you had a low axle (3.31) or big wheels that's a different story, as I'm driving a small 195/70HR14 set of tires on 3.73 gears in my M46 4spd+OD 242GT...

Trannies are a funny thing.

towerymt · 11-20-2002, 04:35 PM

Quote:

Originally Posted by 2 780s

There were euro versions of the 780 turbo B-230FTI & B-234FTI that had the M47 behind them...

Must have been the B204FT/GT because Volvo never made a 2.3L 16v turbo.

[quote:35536ea9e5]The first gear on the M47 is much lower too........[/quote:35536ea9e5]

They have the same 1st-4th ratios (4.03, 2.16, 1.37, 1.00) unless you find one from before about '82/'83.

ZVOLV · 11-20-2002, 04:42 PM

Where would it say M46 or M47 on the tranny? Or is just looking for a OD button a reliable way to tell them apart?

towerymt · 11-20-2002, 04:44 PM

Quote:

Originally Posted by guidom12345

From what i have read in the past, I understand that the m46 is stronger than the m47. How much HP can the m47 hold? Also, is the m47 the same length(same driveshafts) as the m46. Probably not b/c of the OD. Please help. Thanks.

I don't know how much power the M47 will hold because it's not a predictable transmission. I've heard many stories ranging from some that have died behind non-turbos in under 100k miles of normal use, all the way up to some that have held well over 200hp from a turbo, driven hard. If you use proper fluid and change it OFTEN (15-20K miles) and overfill, it should last a while. The M47 can suffer from poor lubrication, so try to get as close to 2L into it by jacking up one side of the car.

If you miss a shift with a high HP engine, I wouldn't expect the M47 to handle it very well. I've abused my M47 quite a bit with general hard driving and many crunched gears from trying to shift too fast, and it's still doing fine behind my B230F at 168K miles. It doesn't whine and it shifts the same as when I got it with 132K.

The M47 has a true 5th GEAR and synchro. It has no overdrive unit, no solenoid, no switch, no wiring, no relay like the M46 Overdrive transmission. Because it has no OD unit, the M47 is shorter and the front half of the driveshaft will be longer than that of an M46.

towerymt · 11-20-2002, 04:51 PM

Quote:

Originally Posted by guidom12345

Where would it say M46 or M47 on the tranny? Or is just looking for a OD button a reliable way to tell them apart?

I was just looking through the Bentley manual, and it appears that you could tell the difference very quickly just by looking at the location of the drain plug. If it's near the front of the trans (front of car) and forward of the fill plug, it's an M46. If it's near the rear of the trans and reward of the fill plug, it's an M47. Having not looked at enough M46/47 transmissions, I couldn't tell you if this is consistant throughout the production run.

If it's still in the car with a shift lever attached, try shifting from 3rd to 5th gear. If you're pulling it from a junkyard, I would expect the shift knob is one of the first things to go, because I've seen a lot of bare shift levers that all look the same.

If there's an OD still attached, it's pretty easy to identify from a 4/5spd.

11-21-2002, 12:17 AM

[quote:485e2ab213]Must have been the B204FT/GT because Volvo never made a 2.3L 16v turbo.[/quote:485e2ab213]

so what engine did they put the 16v turbo on?
:?:

ZVOLV · 11-21-2002, 12:54 AM

Every volvo I have seen in the junkyard is missing the shift nob too!

I havent found any manual turbo 740s yet so i am about to give up.

11-21-2002, 01:55 AM

http://pub5.ezboard.com/ftcvefrm8.sh...picID=40.topic

lilswizzel · 11-21-2002, 03:59 AM

It was a 1.995 liter engine made in italy to keep them under the tax they have on high displacement engines. Chances of finding one of these in running condition in italy SLIM. Anywhere across the pond probably not at all. And tower was correct there has never been a 2.3 16v turbo production engine from volvo

gtlover · 11-21-2002, 08:26 PM

We should put some of this stuff in the FAQs, seems we've debated this one quite a bit.

But, from my perspective, the M46 is plentiful and the steel case versions will take 250HP or so, and the OD ain't half bad. It's nice not to have to hit the clutch again, and they'll take abuse if well maintained.

However, the M47 is lighter (as is the alloy case M46) and you never worry about forgetting to turn the OD off when downshifting. No OD switch, relay, or solenoid to crap out. But - I don't think it will take as much power without some reinforcement. Paul - what did you do to yours to make it a M47'R'?

I think for most of us, the M46 is fine. Beyond that, what's cheaper - replacing your tranny on a regular basis or swapping in a Supra tranny?
This is where we're stuck untill Kenny finishes his T-5 swap kit. :wink:

and for those frustrated with Volvo shift knobs, I'm putting together a universal shift knob and an aftermarket switch. pics and details to come.

towerymt · 11-21-2002, 10:49 PM

Quote:

Originally Posted by gtlover

But, from my perspective, the M46 is plentiful and the steel case versions will take 250HP or so, and the OD ain't half bad. It's nice not to have to hit the clutch again, and they'll take abuse if well maintained.

You sure as hell better be using the clutch to shift to OD if you're pushing 250 through an M46. It's recommened to use the clutch anyway, even on stock motors.

[quote:57ddb02b1e]Paul - what did you do to yours to make it a M47'R'?[/quote:57ddb02b1e]

The M47R comes from Unitek. It has straight cut gears and I think it has a dogleg 1st gear, so it's quite a bit different.

[quote:57ddb02b1e]...and for those frustrated with Volvo shift knobs...[/quote:57ddb02b1e]

I installed a Momo Race Air Leather knob when my M47 knob "failed" and kept coming off on the 1-2 shift.

11-21-2002, 11:26 PM

I plan on rebuilding an M46 for my next project car, but I've only had 100 and 200 series cars (well, one 1800e too) so I didn't know they had alloy M46s in 740s. From reading the above it seems these came in two flavors, is one better than the other?

I plan on building a 2.3l 8v turbo up to about 220-230bhp.

Dan

gtlover · 11-22-2002, 02:39 AM

[quote:b743f0f17f]You sure as hell better be using the clutch to shift to OD if you're pushing 250 through an M46. It's recommened to use the clutch anyway, even on stock motors.[/quote:b743f0f17f]

Good to know I'm not just being overly cautious. And, what, you don't think the OD's cone clutch could take a hard shift with 250 HP?

Good call, I might not of thought of that until I really wished I had a Supra tranny.

[quote:b743f0f17f]I installed a Momo Race Air Leather knob when my M47 knob "failed" and kept coming off on the 1-2 shift.[/quote:b743f0f17f]

Must be nice to just take any old knob you like and not have to worry about what to do with the OD switch.

Thanks for the info on the M47R, I had heard that MikeA put them together but didn't know why they were so special. I assume that the straight cut gears helps to reduce the axial loading on the bearing surfaces? (dang...where's the emoticon for "talking out my arse"?)
BTW how much is one of those beauties?[/quote]

FlatWagon83 · 11-24-2002, 12:57 PM

The M46 is much stronger than the M47, the M47 had a weak casing and is known for failure especially under high horse applications. The M47 is a true five speed. It is sort of impossible to put an electronic overdrive and have it engage by shifting to fifth gear, the linkage would have to magically disengage. I have used both trannsmissions and am much happier with the M46. Although it is nice to have an actual fift gear to shift into, it really doesn't make that much of a difference. The M47 came on my '88 240 which, of course, is not a turbo.

JohnLane · 11-25-2002, 12:32 AM

Quote:

Originally Posted by guidom12345

First of all, i beleive that this post is worthy of the performance board. If not please move it.

From what i have read in the past, I understand that the m46 is stronger than the m47. How much HP can the m47 hold? Also, is the m47 the same length(same driveshafts) as the m46. Probably not b/c of the OD. Please help. Thanks.

For the effort that would have to go into making an M-46 or M-47 actually half assed live, I would strongly encourage you to consider going to the effort of modifying your bellhousing for use with an Americanski five or six speed box and never have to worry about if your trans is going to blow up. I found that using a Quaife straight cut gearset in an M46 with the P-type overdrive (this is the flavor of M-46 with the mainshaft that won't break at the input to the OD in a stoplight battle) was good for up to about 250 horses. I broke both of my (expensive) Quaife gearsets before I got smart (more because I had to!!) and did a Jerico dogbox. Thoughts? JohnLane.

11-20-2002, 04:00 AM	#4
Hank Scorpio Chubfest 2009 Survivor Join Date: Nov 2002 Location: deafing the neighbors, one day at a time.	Well, Paul (volvula) has a m47 in his 245ti and he seems to think it's holding up fairly well, though I know he baby's it. The m47 is much more a true 5 spd than you give it credit for. Just look at the cut-aways of both, oh ya and theres no external OD on that one! No really, it has a whole other gear set built into the trany. __________________ off ~~playin~~ building geetar(s). bbl

11-20-2002, 03:22 PM	#8
Roguls Board Member Join Date: Nov 2002 Location: New York	M47's were NEVER an option on 240T's, not even 740T's (at least not in North America). The fifth gear on the M47 is a true fifth gear, not just a different way of engaging the O/D. If you look at the two trannies side by side you'll see what I mean (the O/D is big and bulky). Roguls New York, USA __________________ Roguls New York, USA

11-21-2002, 08:26 PM	#20
gtlover Board Member Join Date: Nov 2002 Location: The Great Northwest	We should put some of this stuff in the FAQs, seems we've debated this one quite a bit. But, from my perspective, the M46 is plentiful and the steel case versions will take 250HP or so, and the OD ain't half bad. It's nice not to have to hit the clutch again, and they'll take abuse if well maintained. However, the M47 is lighter (as is the alloy case M46) and you never worry about forgetting to turn the OD off when downshifting. No OD switch, relay, or solenoid to crap out. But - I don't think it will take as much power without some reinforcement. Paul - what did you do to yours to make it a M47'R'? I think for most of us, the M46 is fine. Beyond that, what's cheaper - replacing your tranny on a regular basis or swapping in a Supra tranny? This is where we're stuck untill Kenny finishes his T-5 swap kit. :wink: and for those frustrated with Volvo shift knobs, I'm putting together a universal shift knob and an aftermarket switch. pics and details to come. __________________ If you smoke after sex, you need to use more lubricant. ---------------------------------------------------- 2000 V70R AWD 02 C70 T5 Convertible "Black Pearl" 76 VW Westfalia Campmobile "Lizzie" B230F swap underway... Benelli/Wards Riverside 175 Restomod "Moby" 02 Derbi GP1 w/70cc kit "Henry" volvo_bass@hotmail.com

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11-19-2002, 11:35 PM	#1
Anonymous Guest	First of all, i beleive that this post is worthy of the performance board. If not please move it. From what i have read in the past, I understand that the m46 is stronger than the m47. How much HP can the m47 hold? Also, is the m47 the same length(same driveshafts) as the m46. Probably not b/c of the OD. Please help. Thanks.

11-20-2002, 02:44 AM	#2
Anonymous Guest	I've heard the M46 is the better option for higher HP engines. Case in point: They never put a M47 in a turbo charged model (to my knowledge). According to a Volvo Technician I know, the M47 is a re-work of the M46 and when you "shift" to 5th gear, you are actually staying physically in 4th gear but moving the stick engages the O/D (instead of hitting the button). So, the M47 is a considered among some circles as a "true" 5-speed, but I think it is actually a O/D based 5th gear. I'd also like to know if anyone has additional info on the differences between the 2 trannies. Either way, M46 or M47......they'll be a heck of a lot more fun than a AW71!!!!

11-20-2002, 03:13 AM	#3
Anonymous Guest	no, they actually did put m-47's in turbos

11-20-2002, 06:01 AM	#5
Anonymous Guest	There were euro versions of the 780 turbo B-230FTI & B-234FTI that had the M47 behind them... Too bad we Yanks get the short end of the stick... The first gear on the M47 is much lower too........ Andrew

11-20-2002, 02:52 PM	#7
Anonymous Guest	I stand corrected on the M46/M47 issue. Didn't realize they put them in 240 Turbos. Never seen a 240 Turbo with out an O/D button. Same with the 700 series.

11-20-2002, 04:13 PM	#10
JamesDean Board Member Join Date: Nov 2002 Location: Santa Cruz, CA	one question... isnt both the M46 and M47 based on the same 4 speed design, with just an O/D or fifth gear put onto the back half of the housing? it says something like that in Bentley, but i just wanted to ask... Jimmy

11-20-2002, 04:22 PM	#11
Volvo78GT Board Member Join Date: Nov 2002 Location: Plano, TX USA	Yeah basically. There's at least about 3 different designs for the 4speed part (1 steel and 2 alloy designs that I know of) and then, from what i've seen of the early 5 speeds, the 5th gear is just simply that, a gear stuck on the back of the 4 spd gear box... instead of the - supposedly - less reliable OD... My OD runs real nice... its kinda nice to have a auto top gear... flick the OD off and its off. Because mine's nice and firm, its like having a clutchless gearbox... sweet. However there's nothing that beats a true 5speed, or 6 speed for that matter. The M47's that I've seen are realy just 4 speeders that have a 5th gear on the back. From what I've seen I'm not that surprised that they had poor oiling for the 5th but whadda I know? For a NA application up to 200hp I'd say, a M47 is nice (make sure its properly filled eh?) and a NA or Turbo app up to 225-250hp a M46 that's in good shape will serve perfectly well. I personally think that the Supra or Celica tranny is quite sweet. I dont understand a comment that was made earlier... about having a even shorter 1rst gear to make your car faster... I ask why???? Volvo 1rst gears are so annoyingly short!! Just tweak 2nd gear down a bit and you'd have a much better 1rst gear in my opinion... now if you had a low axle (3.31) or big wheels that's a different story, as I'm driving a small 195/70HR14 set of tires on 3.73 gears in my M46 4spd+OD 242GT... Trannies are a funny thing.

11-20-2002, 04:42 PM	#13
ZVOLV "You're their to?" Join Date: Nov 2002 Location: California	Where would it say M46 or M47 on the tranny? Or is just looking for a OD button a reliable way to tell them apart?

11-21-2002, 12:17 AM	#16
Anonymous Guest	[quote:485e2ab213]Must have been the B204FT/GT because Volvo never made a 2.3L 16v turbo.[/quote:485e2ab213] so what engine did they put the 16v turbo on? :?:

11-21-2002, 12:54 AM	#17
ZVOLV "You're their to?" Join Date: Nov 2002 Location: California	Every volvo I have seen in the junkyard is missing the shift nob too! I havent found any manual turbo 740s yet so i am about to give up.

11-21-2002, 01:55 AM	#18
Anonymous Guest	http://pub5.ezboard.com/ftcvefrm8.sh...picID=40.topic

11-21-2002, 03:59 AM	#19
lilswizzel Board Member Join Date: Nov 2002 Location: Portland oregon	It was a 1.995 liter engine made in italy to keep them under the tax they have on high displacement engines. Chances of finding one of these in running condition in italy SLIM. Anywhere across the pond probably not at all. And tower was correct there has never been a 2.3 16v turbo production engine from volvo

11-21-2002, 11:26 PM	#22
Anonymous Guest	I plan on rebuilding an M46 for my next project car, but I've only had 100 and 200 series cars (well, one 1800e too) so I didn't know they had alloy M46s in 740s. From reading the above it seems these came in two flavors, is one better than the other? I plan on building a 2.3l 8v turbo up to about 220-230bhp. Dan

11-22-2002, 02:39 AM	#23
gtlover Board Member Join Date: Nov 2002 Location: The Great Northwest	[quote:b743f0f17f]You sure as hell better be using the clutch to shift to OD if you're pushing 250 through an M46. It's recommened to use the clutch anyway, even on stock motors.[/quote:b743f0f17f] Good to know I'm not just being overly cautious. And, what, you don't think the OD's cone clutch could take a hard shift with 250 HP? Good call, I might not of thought of that until I really wished I had a Supra tranny. [quote:b743f0f17f]I installed a Momo Race Air Leather knob when my M47 knob "failed" and kept coming off on the 1-2 shift.[/quote:b743f0f17f] Must be nice to just take any old knob you like and not have to worry about what to do with the OD switch. Thanks for the info on the M47R, I had heard that MikeA put them together but didn't know why they were so special. I assume that the straight cut gears helps to reduce the axial loading on the bearing surfaces? (dang...where's the emoticon for "talking out my arse"?) BTW how much is one of those beauties?[/quote]

11-24-2002, 12:57 PM	#24
FlatWagon83 Board Member Join Date: Nov 2002 Location: Minneapolis, Minnesota	The M46 is much stronger than the M47, the M47 had a weak casing and is known for failure especially under high horse applications. The M47 is a true five speed. It is sort of impossible to put an electronic overdrive and have it engage by shifting to fifth gear, the linkage would have to magically disengage. I have used both trannsmissions and am much happier with the M46. Although it is nice to have an actual fift gear to shift into, it really doesn't make that much of a difference. The M47 came on my '88 240 which, of course, is not a turbo.