Hey all
I just moved to lethbridge and after doing my auto to manual swap I didn't have a chance to change my 4.11 gears for the 3.73. It's killing my highway mileage now that I'm making the 2 hour drive home often. Does anyone so happen to have set of gears they would be willing to part with for cheap?
Thanks,
-Trev

Welcome to the 'bridge...the airport PYP always has a few Volvo's kicking around (If Greg and I haven't stripped them).

Craig

I'm not too up on what gears would work in the 940 (ie. do older 740 gears work etc.).

There aren't any 900's around in the wreckers, there are 1 or 2 700's at Lethbridge Auto Parts on Highway 4, but they're kinda expensive, and the guy is stupid. Pretty much the airport PYP is the only good place to go, and there's only 240's there....and yeah, most of which Craig and I have already attacked! (The last time I was there, the guy told me they had to crush 2 more 240's, so he gave me a pen, and told me to mark which ones I wanted to keep, as I was the only one who was taking any Volvo parts!)

You really think it's killing your highway mileage? I'm dubious.

My speed calculator says that with the automatic you were turning about 2950 RPM at 120 kph with your 4.10 gears, but I imagine it was closer to 3100 after a bit of converter slip is factored in. With the M46, you're probably spinning 3400. 300 RPM is not going to "kill" your fuel economy. If you install 3.73 gears, you'll be back down to the 3100 RPM range, but I'm still doubtful that you'll get any more than about 1/2 a mile per gallon back.

An automatic 740 Turbo turns about 2800 at 120 and a manual turns about 2700, and the manual gets slightly better economy not because of the 100 RPM difference, but because it's not slipping the torque converter or driving such a large pump (it is driving a small pump for the overdrive, though).

Drive slower. That will make more difference.

The reason I'd get rid of the 4.10 final drive is because the M46 has a silly first gear that's practically unusable with a 3.31, let alone a 4.10.

I guess I should do the same thing when I convert my 940 over to manual. Can a guy use a ring gear off a 240 on the 940 ? I don't even know what kind of rear end is in the 940. I guess I should go out and have a look. I assume it's some variant of a Dana 30 with a limited slip.

I have a donor 240 sitting in my garage with a 3.73 Dana 30 in it. Either that or it's a 3.93. I forget which had the 3.73 in it, my '80 or '81. Would a 3:93 be ok to use as well ?

Roj

Wow, you guys are quick to reply

thanks for the welcome to the bridge! The thought of wrecking yards here had'nt occured to me yet, so thanks! I might have to go check those out once I get my tools up here.

Ugly Duck (it's Matt right?). Thanks for the calculations, and you're right it's not a huge difference, I just didn't go into great detail as to why I want the swap. I do think it would help my gas mileage, and you're probably right it won't be a ton. but also I do find 1st absoloutely useless, I can go maybe 3 meters and then I'm already revved up to 3k. Also I do enjoy driving faster on the highway and I feel horrible revving the engine much over 3.5k for the 2 hour drive.

Roj, I'm pretty sure your car already has a limited slip diff with 3.73 gears in it from the factory! if not though I think that the gears from the 240 do swap over. I seem to remember an article on TB where someone swapped the locker out of a 740 into a 240.....So I think the guts are compatible!

Thanks for all the responses!

The ring and pinion are the same between 7 and 9 (ASSuming the ratio is the same). The later 240 (and earlier 240T) uses a 1031, all 7/9 use the 1031 style ring and pinion.

I had 3.73 and went to 3.31 with the M46. In a turbo car with the heavy flywheel and at the time small turbo, with the 3.73 I'd get full boost ~4K in 1st, then the 13C would choke off all the fun by 5K and you'd hit the next gear and drop the revs a ton since M46s suck. Now I can actually get some speed up in 1st gear and use it and I turn like 3K at 80mph and ~25-2700 at 70-75 MPH (usual interstate speed limit), which is nice and relaxing for a highway car. Fuel econ when I'm driving a little more gently without the tri-bar roof rack is a couple mpg better. Maybe a mile or two over the 3.73 with the 5-speed. Nothing radical, and actually sometimes a little worse with a load on due to lugging it a bit.

With a 16V and a flat flywheel I could imagine 3.73 being a decent ratio. It is a ratio that is common as dirt here. It comes in all automatic 7/900T, and there are TONS of them here. Pulling an axle from a 7/9 is not a fun or rewarding job. Hard to say whether changing the ratio or the axle would be cheaper. I have a 3.73 R&P in decent shape from a 940 you can have for free. I'd love to have spare 4.10 1031 style R&Ps for the puke machine.

Well a couple of months ago I pulled what I thought was a set of 3.73 gears out of a 87' 760 turbo auto, but once I got it home I noticed 4.11 stamped in the serial number on the pinion gear. So if you want we could do a straight trade. I'll take your 3.73, and you can have my 4.11 that I accidentally ended up with as a spare. Sound good?

Volvo doesn't use a 4.11 - they use a 4.10. Any numbers that look to say 411 are coincidence.

If it's the tooth count, it'll say something like 41-11, which is coincidentally a 3.73:1 ratio

Definitely count the teef on your R&P. Numbers and stickers may lie or be irrelevant information. Tooth count never lies.

Yeah...even turning the driveshaft and counting the rotations of the wheel ain't so terribly accurate, is it Matt?

Yeah...we thought we were putting a 3.73 in the 122 until we took the diff out and found a tidy 4.10 stamped on the ring gear...after we'd welded the thing to fit the 122...

n/a low power car?

4.10 is win.

I love my 3.91 - Sure, first gear is suck-o. But jeesus does she climb fast.

I still can't go past quarter throttle (or I get that weird 3 cylinder thing, stupid car, feels nearly identical to if you pull the knock sensor, weird - eh?) anyways, got the car up to 155 kph up Shaganappi (stretch between John laurie and edgemont blvd) - aka Speed Hill. (i see bimmers in my neighbourhood going up it at 170+ every day)

anywho, on the old motor, I never got past 160, and I really dont't think i'm making as much power at 1/4 throttle with the new motor as I was on the old one?

lol

so, yea - gears are win.

- R

I have a 3:73 from a 1031 rear end, that i would trade for a 4:10 as well...so if interested let me know.