88 tercel 3 speed auto -- overdrive possibilities

edt77 · Post by **edt77** » Sun Feb 24, 2008 9:02 pm

I was wondering if anyone has swapped a 4speed auto into their tercel. Is it possible with the 4wd? My objective is to get better gas mileage.

Thanks,
Ed

neonsport · Post by **neonsport** » Sun Feb 24, 2008 9:56 pm

Unfortunately, there's no such thing as an overdrive automatic that'll fit the 4WD Tercel. If it'd been possible, I'd have done it years ago. Your best bet would be to do a stick conversion.

Mac · Post by **Mac** » Sun Feb 24, 2008 11:36 pm

swap out the guts of the tranny?

takza · Post by **takza** » Mon Feb 25, 2008 4:06 am

Bigger tires or a torque converter with a low stall speed?

edt77 · Post by **edt77** » Mon Feb 25, 2008 7:03 pm

takza wrote:Bigger tires or a torque converter with a low stall speed?

I am already on 15in mags so I guess that this is the best that i got for the time being (gas mileage wise).
Is there a torque converter for the 3 speed?

I am really going to look into the manual swap. Does it require a shop full of tools or can it be done in my garage over the weekend if i have the parts?

thanks

Mac · Post by **Mac** » Mon Feb 25, 2008 7:16 pm

you could do it with a full set of wrenches and a ratchet set, plus you usual selection of pliers and screwdrivers.

hardest part would be removing the flex plate and installing a flywheel, those bolts are usually pretty tight.

neonsport · Post by **neonsport** » Mon Feb 25, 2008 8:07 pm

The flexplate bolts are pretty tight. They come right out with an air impact, or you can hold the balancer with a strap wrench while you break them loose.

Typrus · Post by **Typrus** » Wed Feb 27, 2008 9:55 am

A rubber mallet and a standard wrench works too. Thats what I did when I did my silver-swap back in the day.
So my question is whether or not cutting is involved? Change of the wiring harness?
Consider that there is a bit that is auto and manual specific, plug-wise. Important? I realize that the 4wd indicator and reverse are the biggest issues, likely.
You'd have to find a way to splice the reverse indicators into each other. 4wd as well. Not sure if they'd plug into each other, or if its even possible. Differing voltages or whatever.

I know its been done, someone just needs to come up and clarify on this point.
Also... Driveshaft and CV differentiations? The CV's are the same actually. I swapped them from an 86 6-speed to my 85 3-speed.

Post by **ARCHINSTL** » Wed Feb 27, 2008 5:31 pm

Here is the link to Repair Guides for the auto-to-manual swap:
https://tercel4wd.com/forums/viewtopic.php?t=1443
Tom M.

Post by **Petros** » Wed Feb 27, 2008 7:20 pm

Besides the taller tires, you might also look into swapping out the final drive ratio, the '83 and '84 Tercels have a higher final drive ratio. If you have an '85 or newer one this would have the same effect as adding an overdrive, and it is easier than doing a auto to manual change over.

Though I would highly recommend such a swap, but it is a lot of work and you will not likely make up the cost difference for many years of driving (unless you get a "donor" car for free). You might save that for when your tans needs to be replaced anyway.

A few other things to help economy is: a larger exhaust system (again only if you need a new exhaust system anyway, otherwise there is no savings). Advance your timing to 10-12 deg BTDC, make sure your vacuum advance is working, if not replace it. Put narrow tires on the tall rims, and pump them up to 45+ psi. Strip any unnecessary weight out of the car. Get a free flowing air filter, rebuild the carb if it needs it.

Good luck.

neonsport · Post by **neonsport** » Wed Feb 27, 2008 7:54 pm

The higher final drive only applies if you're talking about a manual transmission in a 4WD Tercel. The automatics didn't change, and you won't gain anything by swapping in an earlier final drive.

Post by **Petros** » Thu Feb 28, 2008 3:25 pm

I am talking about replacing the front and rear ring and pinion in the differentials, sometimes referred to as the "final drive". I do not think that it being a manual or auto trans would make any difference since the differentials are is separate housings.

Usually when referring to the "final drive ratio" one is referring to the whole drive train in high gear. If you have an overdrive trans with a low differential ratio, you could have the same final drive ratio as with a non-overdrive trans with a higher differential ratio. So changing the differential would change the final drive ratio.

You would have to swap both the front and rear, and you would have to find a higher gear ratio for both front and rear. If it already has the higher ring and pinion ratio set, than there would be nothing to change to.

neonsport · Post by **neonsport** » Thu Feb 28, 2008 5:07 pm

Petros wrote:I am talking about replacing the front and rear ring and pinion in the differentials, sometimes referred to as the "final drive". I do not think that it being a manual or auto trans would make any difference since the differentials are is separate housings.

Usually when referring to the "final drive ratio" one is referring to the whole drive train in high gear. If you have an overdrive trans with a low differential ratio, you could have the same final drive ratio as with a non-overdrive trans with a higher differential ratio. So changing the differential would change the final drive ratio.

You would have to swap both the front and rear, and you would have to find a higher gear ratio for both front and rear. If it already has the higher ring and pinion ratio set, than there would be nothing to change to.

I understand what the final drive is; what I'm saying is that the differences in final drive ratios were only in the manual transmission 4WD Tercels. Automatic 4WD Tercels and 2WD Tercels kept the same final drive ratios throughout the production run.