Need help keeping the rev's down

Hey guys. Ive done a search, looked around here and there and found some things, but not enough. Here's my prob - my car eats gas like crazy and is geared way too high. I think it has 4.10:1 gears and im running the M46, so when im doing almost 70mph im at exactly 3k rpm's cruising. First gear is almost worthless.

My plan has been to get new R&P gears, like 3.73:1 or 3.54 to solve this problem, but from looking around this is going to cost a lot since the setting of the pinion and the gear is a tough job and is costly. Then i thought of maybe sourcing a whole axle with lower gears, but then i read that if its a year off or what not then the e-brake cables might not add up... abs might be different or non existent, and it could just be in horrble shape. Also i almost never see them for sale around here. So i'm not sure what to do in this department.
Would getting taller tires help me out? if they will then i doubt they'd help me out a lot.

So yea ive looked around but found only snippets of info. I really need some help here. Thanx

*edit* oh yea the car is a 91 740 turbo wagon

If you can find an axle (or diff) from a 1988> 765Ti (the estates kept the live axle) with an M46, you'll have a 3.54 axle that should bolt straight up with no issues and be compatable with the ABS/Speedo/e-brake etc.

just so you know, you got your terms mixed up. You have a set of low gears. 4.10:1 = low 3.73:1 = higher gears. Not trying to be a dick, but it will help alleviate some cornfusion.

as for my .02, I'd wanna keep the lower gears. They're better for ya out of the whole.

will the taller gears mess with the speedo?

In any of the rear axles with the trigger wheel in the differential housing you can put whatever manner of gear ratio you like in there and the trigger wheel will still go around the same number of times as the wheels go round and round. If your speedo trigger is in the trans then you will have speedo accuracy issues with a rear axle ratio change.

Are you quite certain that your car's appetite for fuel is not related to an issue other then the rear axle ratio?? It takes very little to make one thirsty.

My fifty cents in a bet has you being too naughty with the throttle to get descent fuel economy.

Ponder this one..........If fuel economy is such the issue you'd be far better off in something powered with diesel.

My two cents worth. Valued at exactly what you have paid for it.

JohnLane.

low gear, right. i always mix those two terms up.

But other than the gears is there any other way? or is my only option pretty much is to get a replacement axle.

Im not worried about getting stuck in no holes, i got some exprience with that. Im more concerned about highway curising speeds and keeping the gas consumption to a min.

I have seen a 3.31 rear axle ratio in the the back of a 240. Perhaps that ratio can be fitted to your toy??
With certainty changing the complete differential housing to one fitted with a more favorable final drive ratio will be the most cost effective way of getting where you want to be.

A side note.........This is a prime opportunity to fit your little treasure with a limited slip.

JL.

70 mph at 3k is same as in my 242. I think it was just over 24 mph per 1000 rpm which would be 73ish. I used to get 23-24 mpg at 70 mph cruise and 19 mpg being a boy-racer.
If you are going to exert the effort to get a new rear, definately try for a limited slip as JL stated. If you don't want to exert that much effort, bigger tires help but not much. Iss your car in good tune?, done any mods? What is your current mpg?

^^ this is what ive been thinking of. Hoping to kill two birds with one stone.

The thing certainly is fun with 4:10 gears though. Flies like nothing else. But still i miss the cruising speed of around 3k while doing 80mph when i had my 744 with the m46.
With this setup the car feels very erradic (spelling) not linear in the least sense.
I dunno. The thing is this car just recieved a new engine recently. My old one blew so me and my dad decided to take it to a dealer (we've had horrible experience with near-by auto shops, especially this one shop Bohannons volvo specialized shop who fuked me over totaly)
I forget how many miles are on this one but it feels completely different. Rev's past 5k without a problem and seems to like a little too much.

But basically, if i found say 3.73's or lower, i could just put em in with no problem? as in if i found some that are said to be for a dana 30, non relevant to volvo.

i have 3.31:1s in my 744 GLE M46, i was on the highway this weekend...rock solid 3000rpm at about 80mph in OD. my fuel mileage is somewhere around 27-28 on the highway at 70-75mph avg

oh and what size tires are you running?

thats exactly what im looking for. I relaly need to source some used gears or maybe even a whole axle. but im a little iffy about getting the whole axle cuz then u dont really know waht ure getting.

I would encourage you to fit a complete axle with the ratio you like rather then fit a different ratio to your carrier. Not very many folks have the knowledge to set up the relationship between the ring gear and the pinion via shims. This means that you may spend a bunch of dough to end up with a noisy rear end. Volvo rear axles are not prone to problems (aside from pinion seals) when driven by semi-normal human beings (not me) and therefore make a lot of sense to get used.
Get one shipped out to you from the West Coast and it won't be rusted beyond recognition.
Shipping via truck is more affordable then most of us imagine. It gets attached to a pallet and away you go.

Have fun!!

JL.