Modifying an 89 Geo Transmission

[IheartGeos]

Background: Bought a 1989 Geo Metro, rebuilt the engine (I also painted it for extra hp!) and now it's a hoot to drive. Only problem was the third gear was tricky to get into -- push it in and press up-and-left -- and I can't downshift into third. Then I noticed the clutch was slipping -- it looked alright when I put the engine back in, that and I can't get one for under $200 made me decide to wing it. And, last but not least, both the CV joints are bad, and '89 joints are hard to come by. I replaced the worst one, and the transmission oil came out looking like mercury! Bad sign!

Now: Thinking ahead to the summer (when I am out of school for a while) and finally being able to work on the Geo, I had an idea: '89 parts are hard to come by, and Geo parts are fairly modular, so why not slap a '94 transmission, clutch, and CV joints on instead?

Anybody see a problem with that? I am already probably replacing the transmission because the third gear issue, and I need new parts all the way to the wheels, so why not?

Then, I was thinking, I thought I heard somewhere that there is a slightly different transmission you can put in, one that is a little stronger. Any ideas?

[MetroMPG]

The transmissions came with the same gear ratios, but different final drive ratios. You could install a transmission with a taller final, which would lower your RPM in all gears for a given road speed. = slower acceleration, potentially slightly more clutch wear, and better fuel economy.

Project 'nerd gear': taller tranny transplant nets +5.2% MPG - MetroMPG.com

[MetroMPG]

PS - I don't know about the '89s -- if they're fully compatible with the later years. My '98 has the transaxle from a '93 in it.

[TestDrive]

Originally Posted by MetroMPG

PS - I don't know about the '89s -- if they're fully compatible with the later years. My '98 has the transaxle from a '93 in it.

Wikipedia - so who knows how accurate - but FWIW this page indicates:

• Geo Metro was based on Suzuki Cultus
• 89-94 were GEN-II
• 95-97 Geo Metros & 98-01 Chevy Metros were GEN-III.

[Johnny Mullet]

If you drain that trans after getting it warm and refill it with Synchromesh, you might get that gear back. It's worth a shot. I got 2nd gear back on my old transmission this way.

[MetroMPG]

That's good advice, Mullet. 2nd gear stopped grinding on my first Firefly when I went from owner's manual-recommended 70w90 to Synchromesh.