1G Eclipse. A/t to m/t swap.

91-GS · Oct 7, 2012

The Eclipse (1991 GS 2.0) had an automatic four-speed with burned out computer. Drove it with a manual switch for a while but came across a cheap five-speed not long ago so decided to do a swap. The m/t is out of a 1990 Plymouth Laser 1.8, so even though it bolts onto the engine, the clutch does not fit.
Now the actual questions:

1) What would be the best way to mate the two? No part stores around have a 6-bolt Eclipse flywheel. Will one out of a Ram-50 work (heard they used same engines as the GS)?

2) Cleaned up the m/t and found a crack on top of bell housing. About two inches long, not a gap, just a crack. Will that be an issue?

3) Is the swap even worth it? The car is a daily driver, not expecting it to set speed records any time soon.

TylerLorenz · Oct 19, 2012

1. The 2.0 and 1.8L transmissions are completely different.

2. Even though the crack is minor. It could very easily split farther. The Torsion from the engine will pull that crack apart even under easy load.

If you have access to someone who can weld aluminum, and you are on a budget, weld it. I would not recommend using a cracked bellhousing transmission without replacing the bell housing.

3. The swap is a bit more than just a transmission/clutch swap. you have to add a clutch pedal assembly, cut the firewall for the shift linkage, and (don't quote me on this) the wire harness may need adjustments.

91-GS · Oct 25, 2012

Thanks, TylerLorenz.
I'm installing the pedals and the linkage now. Since the transmissions are diferent, will look for a 2.0, at least everything else will be ready. As far as wiring harness goes, there is only one wire on the M/T (the backup light) so it will be a matter of figuring out what wire on the A/T harnes had same function and splicing them together.

Mischif · Oct 25, 2012

The 2.0nt and 1.8 transmissions are the same. As far as the crack on the bell housing you can just drill out both ends of the crack to relieve the stress and it should be fine. You will aslo need to get Flywheel bolts, they are bigger than the flex plate bolts. Besides splicing in the back up lights, you will also have to by-pass the neutral safety switch as well.

91-GS · Oct 25, 2012

One difference I noticed between the transmissions is the input shaft (different number of splines between the 1.8 and 2.0). And the 1.8 flywheel is 5-bolt, not 6-bolt so something would have to get modified. Some suggest machining out the center of the 5-bolt, welding in a blank, and drilling 6 holes in it. Others say that will never work, but suggest drilling the 6-bolt flywheel to accept the pressure plate of the other. Any thoughts on that?

Sean485 · Oct 25, 2012

I am fairly certain the transmissions are exactly the same for 1.8l NT and 2.0l NT. So all you should need is a 1.8l MT flywheel and clutch setup. Dont start hacking flywheels/clutch disks...

As for the crack, get it welded, and make sure your dowel pins are in place to locate the transmission.

Mischif · Oct 25, 2012

Since you have the 2.0nt you will want the matching 6bolt nt flywheel. The transmission you have will work with either a 1.8, 2.0nt, or 2.0t flywheel but its not recommended to use it on a turbo. So with that said, find a flywheel to match your crankshafts bolt pattern., and then a clutch/pp to match that flywheel.

All the 1g dsms have the same input shaft spline count. Its only the output shafts that differed on some of them.

Sean485 · Oct 26, 2012

Oh, I'm sorry. I mis-read that, if the car its going into is a 2.0 then yes, use the 2.0 flywheel and clutch. I thought it was going out of a 2.0 into a 1.8...

91-GS · Oct 28, 2012

That makes matters alot easier since all I gotta do now is get a 2.0 (6-bolt) flywheel and a clutch set to fit it, don't have to worry about having a different disc.

The car that is getting the tranny is a 1991 Eclipse GS 2.0, and the "donor car" is a 1990 Laser (base model) 1.8L.

What are your thoughts on hydraulic VS cable for working the clutch?

Sean485 · Oct 28, 2012

All DSMs use hydraulic. It is not an exotic off-the-wall swap, use the parts off the donor car you will minimize your headache.

91-GS · Oct 30, 2012

Would really like to have a trigger-like button/lever on the shifter to work the clutch so was thinking of different ways of doing it (cable and vaccuum booster, tapping into the power steering pump for pressure, or something crazy like that) but for now the best thing would be to use the factory setup.

1G Eclipse. A/t to m/t swap.

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