Convert from Manual to Automatic

[Cowboy09]

I've got a 90 Chevy C1500, 2WD, 1/2 ton, sportside (what a mouthful!), and I'm attempting to convert it from its original manual transmission to and automatic. Unfortunately, it seems like the crank mounts for the flywheel are different on the automatic version than the manual. It seems really odd that they would have a different type engine build just for a transmission variation.

 

Anyway, I've truly hit a wall and wanted to see if anyone here could shed some light on it for me. Thanks in advance!

 

*Sorry for the double post. I realized after I posted the first one that it was in the wrong place *

[ratchet]

what engine is it? The crank mounts should be the same no matter what motor though. Since your truck is a manual there is a pilot bearing in the crank that must be removed. After that everything should just bolt on. I think you have to change starters if I remember right.

[Cowboy09]

It's the 350 SB.

[StoneyPgh]

It's the 350 SB.

 

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Shouldn't be a major undertaking.

Might need an autorans cross member and drive shaft

[Cowboy09]

Well, that's what I thought, but I've got this problem of the flywheel. The mounts for the auto and manual are different. Once I get the flywheel mounted, it's smooth sailing...until then, I'm hoping someone here can help!

 

EDIT: I'll check that out ratchet. Maybe I'm just blind and missed something.

[bluechevysled]

I've got a 90 Chevy C1500, 2WD, 1/2 ton, sportside (what a mouthful!), and I'm attempting to convert it from its original manual transmission to and automatic. Unfortunately, it seems like the crank mounts for the flywheel are different on the automatic version than the manual. It seems really odd that they would have a different type engine build just for a transmission variation.

 

did you have to change the wiring harness?

[95Sierra2500]

Not to sound like a smart ass, but the flexplate should bolt up to the same spot as the flywheel. However, GM does like to off-set the holes. Check to make sure you're putting the flexplate on the right way...You might be trying to put it on backwards.

[03blackburb]

Couple of things. Wrong flexplate. You have the flexplate backwards. You have not rotated the flexplate on the crank to the correct orientation to match the bold holes.

The crank is the same whether a manual or auto trans is being used. You also do NOT have to remove the pilot bearing from the crank.

[95Sierra2500]

You also do NOT have to remove the pilot bearing from the crank.

 

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This is the only point where I might disagree, as it's been a while since I've had an engine/trans apart...but wouldn't the pilot bearing be in the way of the pilot on the torque converter, which goes into the crank, thus necessitating the removal of the pilot bearing?

[03blackburb]

The from of the converter does not fit into the crank like a manual input shaft. the converter bolts to the flexplate as compared to the input shaft in a manual that is supported inside of the case by needle bearings, then the front main bearing. the rest of the length of the shaft is unsupported until it reaches the pilot bearing. The manual input shaft needs support on both ends.

[ohcrzyguy]

hey man i did this with my truck i used the same starter off the manual, you'll need an automatic drive shaft. mine is a 95 with a 700r4 and i got a painless wiring harness (that was fun) for the sencors to work

[ratchet]

I've never been able to get a torque converter to fit without removing the pilot bearing first.