Regearing a tranny - Toyota Tercel

[Daox]

Alright, the time is comming near when I'm going to need to pickup a tranny for my Tercel. Now, I really want to get the rpms down on the highway under 2000. With the stock tranny I plan on picking up for it I can get the rpms down to roughly 2600 @ 65 mph. This is faaaar from ideal. So, I've been thinking of different ways of dropping that down a bit further. I've heard of swapping 5th gears out and was wondering about swapping in another 2nd gear set into the 5th gear position, but in reverse. With an original ratio of 1.904 this would give a nice low .525. At this ratio my rpms @ 65mph would be a much better 1875 rpm.

Does anyone have any experience with this sort of thing? Yeah, I did read the article about the Escort and I'm hoping my situation is different. I also realize I may need to have some machining work done to get it to all fit up. Thats not a real big deal.

[XFi]

I'm at that point right now too!
Here is my thinking-
My first steps are:
1- Track down all info on compatible (direct swap in or limited modification) transaxle's gear ratios and final drive ratios first. R&R the complete trans if one has the desired ratio.
if this is not acceptable...go to the next step
2- Track down all compatible trans gears or final drive differentials that can be swapped into the trans from 'related' transaxles.
if this is not acceptable...go to the next step
3- Research some racing or machine shops that could 'make' a gear set for you (I was quoted about $700-800 for this when I called around).
if this is not acceptable...go to the next step
4- Pull out hair and scream loudly.
if this is not acceptable...go to the next step
5- Run large diameter tires and keep your speed down.
if this is not acceptable...go to the next step
6- Join EcoModder and search for answers in previous threads.
if this is not acceptable...go to the next step
7- Post New thread titled 'Regearing a tranny' and hope someone has some experience with this sort of thing!

[MetroMPG]

Originally Posted by Daox

Alright, the time is comming near when I'm going to need to pickup a tranny for my Tercel.

Just to clarify - do you call the Paseo a Tercel?

I wish I could offer more advice than XFi already has (I had a laugh when I got to steps 6 & 7).

[Daox]

No, I have a 1993 Toyota Tercel that is undergoing surgery atm. The Paseo is my daily driver.

I guess I'll let you guys know how the tranny stuff goes. Some one has to dive in!

[MetroMPG]

You're the first Tercel-owning hypermiler/ecomodder I've met. Although there was a another Paseo owner that posted a few times @ GS a long time ago.

All of which is to say: you'll have to be the pioneer!

[cfg83]

XFi -

Here's one I noticed on GS :

Congrats to COZX2 on the 100+ MPG fill!
http://www.gassavers.org/showthread.php?p=62366

Thanks, minic6, I posted my gearset info into a thread started by another member. You will find 3 of my posts there:

http://www.gassavers.org/showthread.php?t=3094

I kyped the idea from my friend Tom, an engineer in Michigan. There is a link to his site that shows great pics. Made from stock gears from another Escort trans. I paid $200 for precision grinding of the gears, $55 for the used trans and my brother did the welding. Custom cut gears would probably cost more than my car is worth. Hope all this info is of some use.

Which led me here (good and bad news I'm afraid) :

Modifying Gears for Taller Overdrive
http://sites.google.com/site/diyoverdrive/

UPDATE July 2007: I learned that the Escort "Pony" and "Fuel Saver" models from 1986 to 1990 had a four-speed manual transmission (MTX-II) with overdrive similar to my project. The acceleration in lower gears would not be as good as my car. Also the halfshafts lengths are different for the old four-speed, so it would not be a simple transmission swap. If anyone tries this, please let me know how it turns out!

UPDATE January 2008: The new 5th gear failed and I had to go back to the stock gearing. Oh well, it was fun while it lasted (15 months and 22,000 miles). See the "Durability Failure" link above for photos and failure diagnosis...

However, I was under the impression that the $200 was a lower cost because they were friends. But, I may be wrong, I never asked CO ZX2.

Question : Does your Escort have the same tranny as CO ZX2's Escort?

EDIT : Whoops, are you trying to re-gear the Escort or the Hyundai?

CarloSW2

[XFi]

Sorry Daox...didn't mean to 'jack your thread!

CarloSW2, Daox is modding his tercel, I am modding my escort.
Hyundai's trans isn't getting modded until it is out of warranty.

I didn't see the update on that gear mod (the demise of the gear), thanks.
To answer your question...No, the ZX2 trans is different than the Sdn/Wgn Trans.

I did purchase a 'Pony/Fuel Saver' Trans at a yard but still have to tear it down and compare it to my trans.

[Daox]

Well, since I need to get moving on this I've collected enough info to make a descision. I'll be shopping for two Corolla transmissions. The 2nd gear will be taken out of one of them and modified into a new 5th gear for the other. 1875 rpms here I come.

[MetroMPG]

Do you know yet how extensively you need to modify things?

[Daox]

I just looked at the escort site again and noticed that there was a whole page dedicated to the failure. I'll have to talk this over with some of the guys at work. Its nice to have experts around.

The actual modification hopefully won't be too horrible. I'll have to bore out both of the 2nd gears, turn the teeth off of the 5th gears, and then press them together. Pretty much exactly what they did in the escort article. Luckily I work at a gear manufacturer and I can get access to machinery, or find someone to do it for me (more likely). I also have access to liquid nitrogen and heating equipment to press them together with a tighter interference fit. I don't know yet if any welding will be done, however I would like to stay away from it mainly due to the heat treating of the gears. I also got some tips from our FEA guy at work on how to get better interference fits with more evenly distributed stress so the fit won't fail as quickly.