58SnowWhite

I have a 58 Olds 88. I would like to change the transmission to something more modern so that I can get better mpg. What do people usually do if they want to upgrade their transmission?
My engine runs really good. I believe its the original engine and trans. Cruising in this boat is so much fun... except when I have to put gas in it. Any thoughts?

Olds64

You can retrofit a later model automatic transmission to your engine. It's quite expensive though. You'd have to drive your Oldsmobile for years to come out ahead on gas savings.

joe_padavano

This is neither easy nor inexpensive to do on these cars. As Jesse correctly notes, you'd have to drive the car regularly for many, many years to get any return on investment. Be sure the car is properly tuned and aligned, be sure the original trans is working properly, be sure the brakes aren't dragging. In other words, do all the basic stuff to maximize your mileage with what you have. That will be relatively inexpensive. Swapping the trans is probably $5K, ASSUMING you do all the work yourself (including the metal work to reshape the floorpan). If you will be paying a shop, triple that number.

redoldsman

As has been pointed out, there will be a negative return on the investment you would make in a later transmission. These old cars love gas. It was cheap back then so it was not as big of issue as it is today. In addition to what Joe mentioned, keep your tires properly inflated. We really do need to see pictures of you car. Welcome the ClassicOldsmobile dot com.

58SnowWhite

I'm on the process of getting the olds worked on for much needed maintenance. I'm just worried that there'll be less and less mechanics that knows how to work on these classics that pretty soon it'll take a specialist to work on them... like carburators. I figured if I go for a newer trans, there'll be more parts and I won't need a specialist to work on it.

Olds64

I think that's already come to pass. Already most auto shops will tell you to go elsewhere or quote you such a ridiculous price that you're forced to take the car to a different shop. If you actually do get a spot at a shop that's why classic car owners often hear horror stories of an automotive shop that puts someone's classic in restoration jail.

joe_padavano

Well, "newer" automatics like the TH400 and 700R4 have been out of production for decades. More to the point, if you don't think you can find someone to fix your original trans, what makes you think you'll be able to find someone competent enough to accomplish a much more involved trans swap that requires fabrication. "Mechanics" today are just parts changers. They read the codes and do what the computer tells them to do. They have zero ability to diagnose a problem or figure out a swap. There are a handful of specialists who can both repair the original parts and accomplish the swap. They aren't cheap and if they're really competent they will have a massive backlog. This is why I fix everything on my cars myself (including rebuilding my own automatic transmissions). The vast majority of old car specialty shops out there are completely clueless.

OLDSter Ralph

How long have you owned the car ? What do you really know about it ?

jaunty75

You have to be careful here. I'm sure the price of gas in 1958 was every bit the issue it is today. A gallon of gas that might have cost, say, 25 cents in 1958 is equivalent to about $2.60 today. That's a little less than what it is right now around where I live, where it has dropped into the $2.90 range.

I looked it up. In 1958, the average house price in the U.S. was $19,000. The average annual income was $5,100. In that context, 25 cent gas was just as expensive as $3 gas is now. A new 1958 Oldsmobile would have cost, what, $2,500? That was a pretty sizeable chunk of the average annual income.

Cars got poorer mileage back then compared to today because we didn't know how to make cars any better, not because good mileage was something no one cared about.

Anyone listen to the Radio Classics channel on SiriusXM? I love "The Whistler," and it's always "brought to you by Signal gasoline, the go-farther gasoline." Yes, mileage mattered to people back then.

BangScreech4-4-2

I remember my dad putting his K-code Mustang (on which he'd installed dual Holleys) up for sale in 1970 because gas went from 0.29 to 0.32 per gallon.

To OP: It sounds like you really need one of two things: 1) a resto-mod kind of car which is thoroughly sorted out and fully turn-key, or 2) a new car. The car you have now is neither of these, and it will be very difficult and expensive to turn it into #1.

joe_padavano

I'll try it a little differently. If the OP wants a modified car, go for it. Nearly every car I own is modified in some way or another. Just don't lie to yourself that these mods are needed to improve mileage or reliability or maintainability. No modification will be more reliable than a correctly maintained stone stock factory car. Every mod will have some compromise associated with it and will require some amount of "figuring it out". This means that it won't be as reliable as stock and it won't be as easy to service. Again, don't let that stop you if that's what you want, and if "better brakes" or "better gas mileage" is you you justify it to the significant other, far be it for me to rain on that parade. Just don't kid yourself.

zzcruzin

What city do you live in california? The 58 Jetaway transmission was the better one compared to the late 56 and 57. I rebuilt three of my 57's and they work great. But you are right about finding a good mechanic now days that know about these cars. Good luck with yours.