Before I start ranting about the stupid-ass POS M46 in my 245 that's acting up AGAIN, I was just wondering if someone could shed a little light on why on god's green earth they designed a 4+OD manual instead of a nice, overdriveless 5 speed. That friggin' OD has given me more problems than I can even come up with a cute metaphor for.

Got raped on the smog test last week, too. It passed, but doesn't idle well in the cold (despite having a shiny new preheat installed). Have to do the t-belt myself this weekend.

If the damn thing wasn't long ago paid for and my reg recently renewed, I swear I'd just like to drive it into a huge oak tree and get a nice shiny new Jetta or something that wouldn't let me near it's engine unless I had $200k in specialized tools and diagnostic computers in the garage! GRRR...

I feel much better now. But why the M46 the way it is?

Volvo's been using overdrive transmissions for a very long time.

The first manual transmission that I know of, the M30, had an

overdrive option that allowed overdrive in 2nd and 3rd. These

transmissions were mounted to the B4, B14, and B16 motors. When

volvo went to the B18 motor, they also introduced a true 4sp

manual, the M40. This later in the 1800 had an overdrive options

(that was also an option on the 122 and later the 140/240 cars with

the B20 motors). My impression is that the M45 is almost identical

to the M40, but for some minor differences like being setup to mount

to a slanted motor and so on. Thus, it would have been trivial for

volvo to continue to use the same design for the M46, the overdrive

version of the M45.

The problems with the overdrive setup are:

needs electronics, hydraulics, and mechanics to work correctly

in order to work.

weighs more than a normal transmission, takes more space under

the car

has unfortunate failure modes (reverse + OD=boom).

Otherwise they seem pretty good.

chris

If you put one day of solid work in to it and changed the wiring, relay and seals, it would be good for another 20 years. I think Volvo had such a good transmission in the M45 (4-speed), that they decided not to mess with it and just throw the OD on the back. Look what happened when they tried to make a 5-speed (M47). It is very weak and troublesome.

Rene (M46)

"Look what happened when they tried to make a 5-speed (M47). It is very weak and troublesome. "

I think that I read much more messages aboud the M-46 OD on this board than about my so weak M-47... I think it's weaker but it's weaker than a bullet proof tranny so...

The only M-47 messages I read were about overfilling it.

But consider that i'm here just since this summer.. In my case, my '89 300 000km tranny works great and much better than my father's one(vw golf) in cold weather. When it'S below -5°C, he cannot engage his 2nd gear until he drove it for 10minutes.

I apologize, for regular use, with a few exceptions, the M47 are fine. If you visit Turbobricks, you won't find a single member with one. You're right, compared to a bullet-proof tranny, it's weak.

Rene

I wonder why on earth not an overdrive. The Austin Healey 3000 had a 4sp. with OD in 3rd and 4th. Makes things a little tricky when going from 3OD to fourth because you have to switch out of OD, but if you wind it out in third, then just reach up and flip that switch...Pow!, on comes the power. You do not want to get in a drag race with one of them.

Personally, I like the A-H 100 over the 3000 anyways. I'll take a nice 100 Sebring actually...

Ok I'm done. :o)

rehsper

Good to encounter another recovering Healy owner on the Brickboard. I figure that driving a beautiful, but somewhat undependable, car predestined me to favor somewhat homely, but always dependable, Volvos. I owned two '60 3000s and sold the last one for a downpayment on my first Volvo in 1973. Check out the current auctions on eBay for some breathtakingly restored AHs.

Why design/build a new tranny case and add a gear when you can keep your production 4-speed and add a separate, electrically-operated, transmission to the rear of the existing tranny with lower than 1-to-1 gearing? The move to the straight 5-speed was, IMHO, good for the N/A cars, but once you've seen a 240 making more than 200 Hp and the 5-speed blows apart, then that M46 starts looking mighty nice. BTW, my M46 has held up under HUGE torque loads (at 18 psi in my rather heavily modified 242Ti I'm at about 280 rear-wheel Hp, about 350 lb-ft of torque), no problems.

The people that really know the system (the Guru and V-girl to name two) consider the OD virtually indestructible if you keep fluid in it and don't bypass the 4th gear switch etc. I have to say my M46's with over 200,000 miles on them shift real well, like new. Sure you have to replace an occasional relay, solenoid o-rings, or 4th gear switch but once you get the hang of it it is not too bad. And the M46 is much stronger than the flawed design of the under lubricated M47, or so the turbo guys say.

Well, I did change the fluid about three weeks ago and cleaned the screen and the filters. No leaks or anything. Sealed up cleanly. Thought maybe I didn't fill it up far enough, so this weekend I jacked the beast up on the port side so that it was listing dramatically on its starboard and filled the tranny until there was fluid running out the fill hole and capped it. No change. Also cleaned the contacts on the solenoid and everything electrical underneath.

Basically, it will not shift into 5th unless you are travelling at about 65+ mph. Warm or cold, apparently no difference. Sometimes it will shift at 55 or so, but often it will immediately shift out, sometimes it will wag back and forth. Or there's a concussive sub-sonic vibration to it while it tries to decide what it wants to do. When coasting to a stop, if left in OD, it begins to lurch forward and backward between 55 and 45 -- almost like the clutch is slipping dramatically.

The relay, the switch, the button, the wiring (and -- my memory is hazy -- I think something else -- solenoid?), were replaced on it about 60k miles ago after another long-running nasty bit with it not engaging. Quite sure that was all electrical. It was performing flawlessly up until this sudden shifting problem. I actually trusted it for a little while.

Am wondering if there is something clogging a relief valve inside the OD or maybe the filter and screens need to be cleaned again. Or maybe I got the wrong/bad fluid? Manual specs Type FA. Ideas? I DO NOT want to have to tear this thing out and rebuild it. Too many sad things in 700/900 FAQ sound vaguely like what's going on. Thx.

Watch the address everybody. The Guru is with a new ISP and now I have an address that makes a little bit of sense and is easier to remember for OD problems. It's a bit of stretch rearward for the bushing tool but ODGurubushingtool seemed a bit ridiculous.

On to the OD problem.

The symptoms you are describing are within the realm of deteriorating actuating piston seals IF the dash light does not react with the other symptoms.

The key is your leaving the lever in 4th as you slow down. The seals should hold the OD in until you reach a low of 30 before attempting to drop out then re-engage.

Hopefully the wiring rework was done properly.

Please e-mail me and I will forward a troubleshooting tip sheet that will eliminate any electrical difficulties. Also include a description of the OD symptoms.

Your cost to repair is about $35 to $40 and about 3 to 4 hours. Less if you have a lift.

Duane

ODGuru@kc.rr.com

If it goes into OD and will not come out when you tell it too, it is probably the O-rings in the solenoid that are allowing fluid past a seal. Then the piston can't move back when it should. For repair you need a 1" crow'w foot (thin) split ring pliers and a handful of o-rings. BTDT.

On the other hand if it won't go in, it sounds like the piston seals that are replaceable with a little more work. You have to consult the OD guru. Write if you need his address.

Why don't you pull the OD off of your car with tranny in place and replace the o-rings? It is not a bad job, and the last ime I did it the o-rings, gaskets, and shipping were less than $30. It will take you about 3 hours of work, maybe more if you are low on the learning curve. I did my son's car this summer, and it has worked flawlessly since. See the 700/900 FAQ for great instructions from Duane Hoberg.

Brian-

It's funny that you should post that message today, because my 6-month plus mission to fix my faulty M46 ended this afternoon with an enjoyable test run on the higway. So as you may expect, I'm no longer in the mood to bash my tranny. (Before, I was just as annoyed as you seem to be.)

I'm definitely not an expert in the history of Volvo transmissons, but there's one explanation for the existence M46 that I've heard about makes sense to me. As the story goes: Waaaaay back before the oil crisis, Volvo developed this nice, sturdy little 4-speed manual transmission that they used on quite a few of there cars. (Don't remember the proper designation for it...M45 comes to mind.) But since the final drive ratio for this unit was 1:1, gas mileage wasn't all that great for cruising at highway speed. To have any chance at competing with 30+ mpg Japaneese shoeboxes, Volvo had to increase their efficiency and one of the easiest ways was to put in a transmission with a final drive ratio greater than 1:1. Since they had a perfectly good transmission already, they opted to bolt on the Laycock de Normanville, (British built), OD to act as a fifth gear. Depending on the rear end, the car could now cruise at 60 mph and only rev at something like 2300-2500 RPM. Poblem solved. If anyone has a different story, please post it.

So now I have to ask: What's wrong with yours? Perhaps one or more of us can direct you to a successful repair. There's a great deal of knowledge available through this board and I've had a lot of success in the past.

Close, but no cigar. Volvo was using the Brit OD unit on 4-spd transmissions well before imports from Japan or the '73 energy crisis were an issue. Look underneath any 1800 or 142E.

Sounded logical until the words 'electronic' and 'British' were used in the same paragraph. Ugh. No wonder.

Why does it say I posted the above?? It was Brian.

That was REALLY weird......

Yes - those 2 words are extremely scarey together (take it from an old MG owner/masochist). You know - "Why do the British drink warm beer? Because they have Lucas refrigerators" or " Lucas - the Prince of Darkness". I'll stop now... that was a long time ago.

I agre with you Ive had plenty of problems with 4+odwired the wholw thing from the switch to the floorboard and in doing that i disconected the wireing to the switch. couldn't connect it cuase my car has lowering springs. i was going out of town that night and couldn't fix it 60+ miles

in 4th gear 3000-4000rpms the whole way never had more fun in my life!

> in 4th gear 3000-4000rpms the whole way never had more fun in my

> life!

boring life? ;-)

Ooohh, that's rough. But, from what I gather from other threads, you don't go over 3500 rpms at all!

Shift light...HA! Just run 'er up till you hear the valves float!! ;o)

Will Repsher

> Ooohh, that's rough. But, from what I gather from other threads, you

> don't go over 3500 rpms at all!

you should have been on the road when I test drove her ;-)

in any case, the comment was pointed most sharply at the fact

of 4000rpm being the highlight of one's life..

now, as exciting as hurling a giant blue brick down the highway

at 75mph to buy cheeto's may be; I must say, I would be lying if I

told you it were large enough to overshadow the rest of my existence.

in fact, it's quite clear to me that the most exciting point in my

life had nothing to do with cars at all, not even such as a Volvo.

therefore, it is on this reason that I based my conclusion of Jake's

level of entertainment on this planet..

now, let him feel free to contest this claim.. since I see no response

as of yet, I must assume that he concurs with my judgment.

so, with that statement made, I will end this portion of my post.

> Shift light...HA! Just run 'er up till you hear the valves float!!

> ;o)

but, its so orange and Swedish.. how could I resist such charm?

those valves love me, friend. can you say the same about yours? ;-)