Fuel Economy and tranny

No. Assume fuel prices are $1.80 per gallon and you get 14mpg on the old tranny, thus your cost is 12 cents a mile, and with 17mpg on the new tranny your fuel costs are now 10 cents a mile. So the new tranny saves you 2 cents a mile.

Now assume you find a junkyard tranny cheap, your looking at $500 for a questionable tranny just to get overdrive by the time you buy all the miscellaneous stuff, and this is assuming you do the swap. Now, how many miles will you have to drive to break even? $500.00/.02 is 25,000 miles. Do you even drive 25,000 miles in a year in this van?

This is why people who have single-paned glass in older homes don't bother replacing all their windows with new double-paned windows. The returns on the investment just aren't there unless your going to be living in the thing for 20 years.

Ted

In a year? Surely the transmission will last longer than that!

I have a 97 Custom Van (2500) with the same engine and transmission combo you have. I get 16-17 mpg on mine.

I don't know what the rear end ratio is, but can probably find out from the vin number or something.

I doubt that a tranny change or installation of a two speed aftermarket unit is worth the money.

We're talking about an el Cheapo junkyard, tranny here. And a Dodge trans to boot. 25,000 is being generous :-)

You've got a lot of good points there. Thanks. I guess it doesn't add up.

That's not too bad, I was just going by the stats, not actual real mileage, since I just got it, and haven't run through a full tank yet. I won't worry if I get 16 or 17 mpg. I'm pretty conservative driving it anyway.

It's marked somewhere, under the hood I think. I forget, but I believe it's the lower number that's available. 3.73 or 3.43 or something, as opposed to

Thanks, I'm guessing you're right. Unless there's some real easy/cheap way to change the rear drive, (like swapping a rear sprocket on a bike), I guess I'll just leave it.

Everything else is great, pwr windows doors, cruise ctrl, remote entry, alarm, with the exception of the tilt steering, but that's a separate thread.

You can usually find complete rear axles in junkyards for on the order of $200-$300. That's much easier than changing the ring and pinion to a new ratio on a salisbury (rear cover plate type) axle. Of course if it were an old Hotchkiss type 8-3/4, it would be INCREDIBLY easy since all you change is the center section. But that axle went out of production in '74.

As long as its the same type axle, you can just hook your existing driveshaft and springs up and go, and I'm guessing that 90% of Dodge vans use the corporate 9-1/4. Rear ends last forever unless they've gotten full of water or run out of fluid- they're almost never what puts the van in the junkyard. As long as it turns smoothly and has the ratio you want, go for it.

On the other hand, you can't walk out of a junkyard with an overdrive transmission for under $500, AND you'd have to rig up manual controls for the convertor lock-up and the overdrive, which are normally controlled by the engine computer.

Don't be stupid while trying to be funny. Rear-drive Dodge automatic O/D transmissions used with the 5.2, 5.9, V10, and Cummins diesel are just the old A-727 3-speed with an electric overdrive unit added in the tail housing. They last forever- certainly better than a GM 4L80E or Ford equivalent. This isn't a front-drive (A-604) minivan transmission we're talking about.