Crankshaft is too long for torque converter pilot hole?

[jamesejam]

My 1987 Cutlass is in the shop because the flexplate was all torn up. He thinks it's because the torque converter wasn't snug with the flexplate. Now I can't confirm any of this because I haven't looked at the transmission and it's in the shop now, but apparently, per the mechanic's words, on my 307 the crankshaft fits into a pilot hole on the torque converter. The problem is that the crankshaft sticks out too far and won't allow the torque converter to mate with the flexplate, so he's shaving down the crankshaft to fix this.

The weird thing is, this is the original torque converter, so it should've always fit perfectly. Also, I thought the crankshaft stopped where the flexplate bolts to it - I didn't know it went through the flexplate and fit into a pilot hole on the TC. Does this problem make sense?

 

[pontiacgp]

are you sure you have the right flexplate and that it's not mounted backwards? And is that the correct torque converter?

Crankshafts are balanced so I wouldn't suggest any material be removed from it.....

 

[jamesejam]

So he actually shaved a few millimeters off the nub on the torque converter so it now fits snug against the flexplate. It runs OK now when the car is cold, and maybe I just need to get used to the V8 vibrations since my last 2 cars were a 4-cyl Saab sh!tbox and a transverse-mounted 6-cyl Ciera. But it seems like it vibrates a little more than I'd like it to, after the car warms up. Also, when I rev the engine in park and let off the gas, I hear a little spinning noise from under the car for just a second. It's as if I'm hearing the torque converter stop spinning. I can hardly hear it over the engine, but it is audible when I listen for it with my head out the window and I can tell it's coming from near the transmission. I can just barely hear it with the windows closed and the radio off. Is this anything I need to worry about, or is this probably just a quirk that won't matter for another 50k miles? He gave me a 4-month, 4000 mile warranty on the work done, so maybe I'll just wait a few months and see what happens...

 

[pontiacgp]

if you had to shave anything for a stock set up then there's some part(s) that's not right...

maybe I just need to get used to the V8 vibrations

maybe you need to find another mechanic

 

[joe_padavano]

if you had to shave anything for a stock set up then there's some part(s) that's not right...

maybe I just need to get used to the V8 vibrations

maybe you need to find another mechanic

X2. There is no need to "shave" anything. Note that on an Olds motor, you cannot install the flywheel backwards - one of the bolt holes is offset to prevent this. You would need to leave that bolt out or to file the hole. Either way, anyone with a clue would know something was wrong.

 

[pontiacgp]

I'm thinking it was the wrong torque converter....

 

[jamesejam]

Well I already paid the guy $900 to fix it, so hopefully he did it right. I don't have the time or the space to pull the transmission and look at it myself. He said he tried 2 different torque converters just to be sure, and neither of them fit perfectly, so he had to shave just a smidgeon off the one. He thinks this fitment problem is what tore up my original flexplate. He seems pretty knowledgeable, and he's been voted "best mechanic" by the local paper and online reviews, so I don't think he's dumb. I just wish I could look at it myself, and I hope it doesn't ruin the transmission. I can buy a new flexplate and a new torque converter eventually, but I'd be super pissed if the transmission got ruined. If he did shoddy work, I hope it breaks in the next 4 months/4000 miles.

 

[pontiacgp]

The button on the torque converter is supposed sit in the pilot hole of the crankshaft. I've changed over a dozen trannys on a G body and have never had any fitment problems. If that torque converter is the right one then what has probably happened is the button on the torque converter was damaged when the flex plate was wobbling around and that's why it won't fit now. The crank's material is stronger than the torque converter's material so the crank is probably ok but the diameter of the pilot hole should be checked. The splines on the transmission shaft and the splines in the torque converter should have also been inspected. The mechanic may be a real good but everyone at some point makes mistakes and/or overlooks something.....