m46 or m47

[Anonymous]

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.

[Anonymous]

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!!!!

[Anonymous]

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

[Hank Scorpio]

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.

[Anonymous]

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]

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

[Anonymous]

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]

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]

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]

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]

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]

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]

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]

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]

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.

[Anonymous]

[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]

Every volvo I have seen in the junkyard is missing the shift nob too! :lol: I havent found any manual turbo 740s yet so i am about to give up.

[Anonymous]

http://pub5.ezboard.com/ftcvefrm8.showMessage?topicID=40.topic

[lilswizzel]

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]

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]

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.

[Anonymous]

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]

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? :lol:
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?

[FlatWagon83]

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]

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.

[Roguls]

"It's nice not to have to hit the clutch again, and they'll take abuse if well maintained."

The clutch should be used when engaging and disengaging the O/D.

[Anonymous]

i was wondering how hard it would be to make a m47 w/ od, to make a volvo 6-speed?

[gtlover]

Are you a machinist? Do you have access to a foundry? That's kinda what it would take.

I like John's suggestion better: adapt an existing tranny. They've had 6-speeds in Vettes, Bimmers, and Supras just to name a few. Find one with a suitable input spline, adapt a bellhousing and clutch, get a driveshaft and shifter fabricated, and enjoy the benefits of rowing. Yeah baby, close ratios and overdrive!

Anthony Hyde or John Lane could give solid figures, but it seems a Supra or domestic 5-speed swap would be more economical and easier, and work pretty damn well. It's hard to justify a 6-speed if you don't have the power to hit 150 on the front straight of your average track. I know some of us have bricks that could do it, though!

[U.N.C.L.E.]

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.

Hi! My first post.

T-bricks is a great forum!

Thats why I think it's bad that people like the one I'm quoting spread erronious information.
The 960 turbos had a B234FT with 204HP. I'm not saying it's a common configuration, but there's actually quite a few of them.

[Homer]

Holy post resurrection Batman!!!
Oh and welcome to the maddness that is Turbobricks :rofl:

[towerymt]

Hi! My first post.

T-bricks is a great forum!

Thats why I think it's bad that people like the one I'm quoting spread erronious information.
The 960 turbos had a B234FT with 204HP. I'm not saying it's a common configuration, but there's actually quite a few of them.
Documentation, please. I've never seen pictures or specs for such an engine. I have seen plenty of references to the B204FT/B204GT in the 960 Turbo.

http://wwwrsphysse.anu.edu.au/~amh110/16_valve_turbo_volvo.htm

http://www.bbt-automotive.de/zks/inf_volvo.htm

http://www.volvoniacs.org/forum/thread.jsp?forum=46&thread=1439

http://volvolandia.com/markkina/index.php?board=1;action=display;threadid=5987

http://www.uwm.edu/~keobrien/car/Misc/b204ft.JPG

[U.N.C.L.E.]

http://www.partsforvolvosonline.com/product_info.php?name=900+Series+90'-97'+Rear+Brake+Pads+(See+description+for+applicati ons)&products_id=2113

http://www.tomco-inc.com/Catalog/34mass%20air%20flow%20sensors.pdf

There are also part numbers for intake and exhaustmanifoils for b234FT. I'll come back later. Next time you change oil, look at the oil filter. It says b234FT on oem oil filters. I can't find one for sale right now, but I'm sure there will be one again some time. The first time I saw one, was in Minnesota, so you should probably have them over in the US as well.

[Snorko]

B234FT...??? Pure fantasy, faulty non OEM supplier lists. That silly list has the 16 v 940 under "6-cyl". Even the 960 Turbo had a B204 engine. The 2,3L Turbo engines where all 8 valve.
M47+Turbo??? The M47 breaks easilly with a n/a engine. Turbo cars have either M46 or M90.

[MikeHardy]

dave has a 89 (i think) 740 turbo, B230ET with M47, VIN shows it as being stock box.

[Unregistered]

M47+Turbo??? The M47 breaks easilly with a n/a engine. Turbo cars have either M46 or M90.
If it broke easily with n/a engine, I'd have broken mine by now.

Early 700 series turbo cars in the US had the M47. Not very many years, though.

[foggyjames]

Maybe this doesn't matter anymore, but the M47 is an M45 with a 5th gear section bolted on the end of it (where a 46 has the OD of course!). In that sense its kinda like and OD....but its a proper/normal gear.

I'm not even gonna enter the 'how strong is it' debate, other than to say that I know a number of people pushing over 300bhp (crank) through them, albeit at high RPM (so less torque than you might be expecting)...plus they treat them very gently.

cheers

James

[volvorsport]

yeah , ive got an M47 , behind my motor , it doesnt really get babied , and the clutch is on its way out , so yes they can hold 230 ft/lbs torque as indicated by the dyno .

I think vadis said mine should have an M46 - although M47 was on the list . i must say i prefer the 5 speed , since it keeps the OD from popping out at 120mph , most disconcerting .

The main worry with these boxes is lubrication since it was a friday afternoon design thing , oh yes lets have a five speed . there was a change in 87 where they became better ,ATF fluid must be used since it wont oil the rear bearing and whoa out comes 5th gear .

[Boosted2003]

B234FT...??? Pure fantasy, faulty non OEM supplier lists. That silly list has the 16 v 940 under "6-cyl". Even the 960 Turbo had a B204 engine. The 2,3L Turbo engines where all 8 valve.
M47+Turbo??? The M47 breaks easilly with a n/a engine. Turbo cars have either M46 or M90.

Im not going to agree with you on this one. I have found quite of few things wrong with vadis and even with peoples stories. I wouldnt be surpised if volvo didnt pump out a few b234ft engines on a small amount. Volvo has never has a set standard they have always changed little things.

[robs89volvo]

i bought a 89 740t with the m46 in it and the od went out the second week i had it and the next month after i replaced the od the tranny blew up in it so i went with the m47 and i like it alot better now i might have the numbers wrong but you know what mean. ill have to put some pics up so you guys can see the damage that it did

[U.N.C.L.E.]

B234FT...??? Pure fantasy, faulty non OEM supplier lists. That silly list has the 16 v 940 under "6-cyl". Even the 960 Turbo had a B204 engine. The 2,3L Turbo engines where all 8 valve.
M47+Turbo??? The M47 breaks easilly with a n/a engine. Turbo cars have either M46 or M90.

Im not going to agree with you on this one. I have found quite of few things wrong with vadis and even with peoples stories. I wouldnt be surpised if volvo didnt pump out a few b234ft engines on a small amount. Volvo has never has a set standard they have always changed little things.

I regret that I made the post, before I had more substatial evidence. It was my spontaneous reaction because I've seen the sticker in the engine bay.

As far as goes for the m47. I think it is sort of a myth that they are so weak. I have a friend with a 740 turbo that dynoes 214 hp at the wheels. He claims that it is people who don't know how to shift that breaks them. The fact that volvo did not use them widely for their turbo cars (I did not know they did at all) does not mean it was because the m47 was too weak, it could be other factors. Take the 1970 1800E, they got a ZF gearbox just to handle 130 HP SAE (122 DIN). The next year sombody put an end to the madness, and the m41 came back.

I've decided to find out for myself, so I've bought an m47II to put behind my 230 turbo. Mabye I'll join the m47 haters union. But what I've seen in my friend 740 made it impossible for me not to try it out. It might be an icredible variation in build quality that causes all the different opinions.

[r.friborg]

Hello

The m46 is not nice.
If u drive it hard the od will start to spin internaly.
The m47 is better, there it depends how u change gears how long it will last.
m47 is a true 5 speed.
I have changhed 3 m46 gearboxes in my car in a month.

Now I have a m47 "temporarly", and it is much better.

If you fill the m47 whit more oil than recomended it will last better.

Robert the swede

[Fuse]

There are diffrent versions of M47. First ones were weaker. In 300-series there's M47R MKII and people are pushing over 250hp through and some over 300 so I guess with proper use it will take some power.

[Fuse]

B234FT...??? Pure fantasy, faulty non OEM supplier lists. That silly list has the 16 v 940 under "6-cyl". Even the 960 Turbo had a B204 engine. The 2,3L Turbo engines where all 8 valve.
M47+Turbo??? The M47 breaks easilly with a n/a engine. Turbo cars have either M46 or M90.

Volvo made 16v B21/B23 motors also. With R-Sport head though and it was an aftermarket engine. But still a Volvo-made. ;) Mainly in rally cross use though...

http://wwwrsphysse.anu.edu.au/~amh110/all_gifs/Turbo%20page%20gifs/16V_RSport_carb.jpg

228hp@7200rpm, twin Solex, N/A. (Turbo versions were also made but haven't seen anywhere else than in rallycross 343/360)

[Snorko]

[QUOTE=Fuse] Volvo made 16v B21/B23 motors also. With R-Sport head though and it was an aftermarket engine. But still a Volvo-made. ;) Mainly in rally cross use though... [QUOTE]

Come on! We are talking about real production runs here right? Like all manufacturers they try a lot for motorcross-markets and pre-production experiments.
Volvo made 740/240's with the 5 cyl for test purposes before producing the 850.
That does not mean you can buy it at the nearest dealer... unless you have an astronomic budget to spend on a Volvo. The 16v R-sport engine probably costed as much as a 240 Turbo. I guess you could have had the dealer install whatever transmission in a car as long as you pay for it. Just take a look at the "Evolve" projects in California now. Similar stuff as the R-sport department did when it existed.
Anyways a m47 on a HPT would be asking for trouble. You can get them for free and it doesent hurt anything but your pride when you bust one by flooring the pedal in 3rd.
I first had a M45, then a M47, alloy M46, now a iron M46.
The transmissions all broke the same way, full power (0.95Bar boost) in third gear. No rough shifting.
A Getrag 262 is now on the livingroom floor getting prepped for installation. I would like a M90 but the price is just ridiculous compared to the Getrag. $1000 v.s. $50
Save some time and effort and get a T5, getrag or something that can take a little torque.

[foggyjames]

Anyways a m47 on a HPT would be asking for trouble.
If you mean stock HPT (ie: a B230ET / FT)...they were supplied like that from the factory, and are well documented as making it well into 6 figure mileages...can't be that troublesome!

I'm prepared to concede that if you abuse the shifts on an M4x box they don't last long. They obviously can't take high torque either. Having said that, there are several people in the UK developing the kind of torque necessary to see above 300bhp, without breaking M4xs. One guy gets above 300bhp through pretty high RPM (ie: less torque than achieving 300bhp at 6000rpm), but another makes it at 6k. He said M4xs are fine to 330bhp, but start breaking at 350. Of course there are a lot of other variables here - its not just engine torque.

Of course there are people who are breaking them because they can't take the power. However, I think there are also people who break them because they need lessons in driving a manual car :-P

cheers

James

[neurot75]

maybe i missed it or over looked it, but what are the final drives on the m46 and m47? comparing the OD on the m46 and the 5th gear on the m47

[foggyjames]

My M47 is a (edit: 0.83...what was I thinking?!). I think that's shorter (higher RPM for a given speed) than the OD on the 46.

cheers

James

[volvorsport]

as before , mine survives behind 230ft/lbs torque , so it s quite capable .

[TheJoyOfSix]

O/D on the M46 is 0.79:1

[rick3612]

A question for the M46 folks. I have a '78 M46 (10 spline input shaft) and I'm considering getting an '80 M46 (22 spline input shaft). Is it possible to put the input shaft off of the '78 into the '80 M46? Are there any noticeable shifting difference between the two trannies? Thanks

[samyboy]

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.

what :???: that was the thing that made the old 944TD sooo cool get to a high speed in 4th gear and hit the button to get the huge kick in the pants (when i was younger i thought that was a turbo :oops: )


and on the M46/7 topic my 240GLT its 4 speed OD dont know what gearbox it has but its got 192K on the original one and ive given it a heck of alot of thrashing 3rd gear clutch kiiling burnouts but still all works super fine

[JohnLane]

Get the clutch disc for the fine splines and be happy........Fine splines when lubricated will slide more easily making it less likely that you will crunch in to reverse or first.

JL.

[swedishiron.com]

A question for the M46 folks. I have a '78 M46 (10 spline input shaft) and I'm considering getting an '80 M46 (22 spline input shaft). Is it possible to put the input shaft off of the '78 into the '80 M46? Are there any noticeable shifting difference between the two trannies? Thanks

Why would you want to tear apart transmissions to swap the input shafts?
It would be much easier to match the correct clutch to the correct transmission...
There should be no difference in shift quality when comparing an '80 to a '78.
The only difference will be in the overall amount of wear that either tranny has incurred.
JD