Manual to auto swap?

[MDrex]

My new T has a Chevy 3-speed manual and Chevy 305 V8, which I think are from an older pickup. The car also has a 9" Ford rear with 3.50 gears. I'm not a huge fan of the manual. I think it would be easier to drive and give me more room in the car with an auto. The shifter also has no feel to it, so its just not that nice or fun to shift through the gears.

What parts would I need and what would I have to do to swap to a Chevy 350 auto trans?

I know I'd need a trans, shifter, converter, maybe move the trans crossmember and maybe change the length of the driveshaft. I assume I would need a different flexplate instead of the manuals flywheel and also a different bell housing. Am I missing anything? Is this going to be a major pain to do? Any help or advice would help greatly.

 

[old round fart]

Don't forget to remove the bushing in the back of the crank. If I remember right the converter won't go in deep enough if you don't. I seem to remember putting wheelbearing grease in the hole and driving an old input shaft in the hole until it pushed it out.

 

[RPM]

Don't forget to remove the bushing in the back of the crank. If I remember right the converter won't go in deep enough if you don't. I seem to remember putting wheelbearing grease in the hole and driving an old input shaft in the hole until it pushed it out.

You won't need to take the bushing out on a Chevy. You won't need a bell housing as it is made as part of the trans.
Tranny
converter
flexplate
flexplate bolts
converter bolts
down shift cable
trans mount and bolts. Could be metric.
fill tube
maybe a starter, depends which one is in there now.
shifter and linkage
might need new bolts to bolt trans to block, if not the right length
slip yoke should be the same.
Might need to shorten or lenghten
Trans fluid

That should about do it. Is ATI still there in Baltimore? They used to be over near the Social security building.

 

[MDrex]

What exactly does the down shift cable do and what does it connect to? Thanks for the info, this sounds like it might be too bad. Maybe I'll tackle it as a winter project.

 

[donsrods]

You will also need a cooler for the fluid to run through.

Don

 

[Rick]

What exactly does the down shift cable do and what does it connect to? Thanks for the info, this sounds like it might be too bad. Maybe I'll tackle it as a winter project.

It does exactly that when you throw the boot to the throttle on a normal car you kick into passing gear which is down shifting from 3rd to 2nd which works fine on a 3000 lb. car but your under 2000 lbs.there really is no need for this on your car.To answer your question it goes to a sliding bracket on your carb.and since you have a stick i dought if you have this bracket.A good tranny shop can take your cable off for you if your not up to it.

 

[MDrex]

OK, that's what I thought it was. Sounds like I really won't need it, so it will just make the whole project easier to ditch it.

What do shops normally charge to change the length of a driveshaft?

 

[Rick]

OK, that's what I thought it was. Sounds like I really won't need it, so it will just make the whole project easier to ditch it.

What do shops normally charge to change the length of a driveshaft?

You'll need a different front yoke also.I don't know the price i had a new one made and it cost me $175.00
thats $20.58 an inch.LOL

 

[RPM]

I think the 3 speed manual and the turbo 350 can use the same slip yoke. The turbo 400 has a bigger yoke. To lengthen a drive shaft the entire tube has to be cut out and a longer tube installed. Turbo 350 come in 3 different lengths so he might not have to lengthen a shaft but maybe shorten one.

 

[MDrex]

If I do this I'd like to do it for less than $700. I have found a nice tranny with converter for $150, but the guy is open to offers. I'll still need a flex plate since he's keeping his, I'll need a shifter too and the driveshaft redone. I will have to recalibrate the speedo, but thats not a big deal. I may need to get a new starter also, depending on the number of teeth on my flywheel and on the flexplate I get.

Can I change just the gear on the starter if the number of teeth on the flexplate is different?

 

[RPM]

If I do this I'd like to do it for less than $700. I have found a nice tranny with converter for $150, but the guy is open to offers. I'll still need a flex plate since he's keeping his, I'll need a shifter too and the driveshaft redone. I will have to recalibrate the speedo, but thats not a big deal. I may need to get a new starter also, depending on the number of teeth on my flywheel and on the flexplate I get.

Can I change just the gear on the starter if the number of teeth on the flexplate is different?

The starter teeth are all the same, the difference is in the starter nose. They have different offsets, meening the bolt holes are in a different place. You should be able to get the right flex plate so you don't have to change the starter. Count the # of teeth on the manual flywheel before you order the flex plate and get the same amount of teeth.

 

[MDrex]

Thats what I was thinking I could do. I did some quick research and it looks like most of these engines either had 168 or 153 teeth on the flywheels or flexplates. I'll just count the teeth when it comes apart and order the flexplate last.

 

[RPM]

There are 2 different patterns on the converters, but the flywheels have both patterns dilled in them.

 

[Martin]

Or if you dont feel like counting teeth, the 168 tooth flexplate is 14' diameter, and the 153 tooth is 12 3/4'. Also the starter for the small one has the bolts straight across from each other, while the big flywheel starter has staggered bolts. Check your flexplate against your torque converter. Most flexplates are universal in that regard, but I have seen some that were not.

 

[MDrex]

Thanks Martin, that way makes it much easier than couting teeth.

Now, what about shifters? Will I need a floor mount, tail mount or one that mounts forward on the trans more? I'm sure you guys can't answer that, but any advice helps.

 

[Rick]

Thanks Martin, that way makes it much easier than couting teeth.

Now, what about shifters? Will I need a floor mount, tail mount or one that mounts forward on the trans more? I'm sure you guys can't answer that, but any advice helps.

A tail mount will pretty much put the shifter into the seat.

 

[MDrex]

A tail mount will pretty much put the shifter into the seat.

OK, so I'll need something that mounts more forward of that. I figured that might be too far back, but wasn't quite sure. I haven't gotten the car in the air to take a good look at the bottom yet. I plan on doing that soon and taking some measurements.

Does anyone know the overall length of a Chevy TH350?

 

[RPM]

Maybe one of the cable shifters would work for you. That way you can put the shifter wherever you like it.