Truck is parked

[Russell]

Sigh, those of you who visit the engine and drivetrain section probally already know that I didn't install the tranny right. The flexplate appeared to be bent as I cranked the truck truck over, I swapped a new flexplate on, and it still did as much, so that means the crank is bent. Transmission is probally fried too. So the GMC is off the road for the winter. Gonna get my little Toyota pickup registered and insured, drive it for the winter. I guess this is as good of time as any to start swapping stuff between the two trucks. The cab, wiring, driveshaft transmission and front clip from the GMC are going to the Chevy. I'll also be buying and installing new heads on the TPI 350, breaking the cam in on it, then installing the TPI, and eventually installing it into the ex-chevy. I also need to do some sheetmetal repair on the cab of the GMC, needs new cab supports, along with fixing little dings in the rest of the body. I hope to have it running the TPI 350 / TH400 combo and have it in primer by spring next year.

[rage'nrat638]

GOOD FOR YOU MAN... IT'S WINTER ANYWAY.....
THING'S HAPPEN FOR A REASON......

YOUR TRUCK MUST HAVE BEEN CRYING FOR HELP !!!!!!!

[1972C10]

How does a crank get bent?

[Russell]

I dunno Don, I would have guessed the flexplate to bend first, but I know the new one is straight, and it still wobbles something nasty.

[1FaastC10]

you cant bend a crank. it will break, not bend. my bet is that the new flexplate is bent too. all the bolts tightened to proper torque and in the proper sequence?

[Russell]

Originally Posted by 1FaastC10

you cant bend a crank. it will break, not bend. my bet is that the new flexplate is bent too. all the bolts tightened to proper torque and in the proper sequence?

Yeah, they are. I put both flex plates down on a flat level surface, and both are perfectly flat. Just to make sure, I put the new one on, and it wobbled too. There is no other way to explain a wobbly flexplate than a bent crank

[1FaastC10]

cast iron wont bend, the crank is made from cast iron. what sequence did you use to torque the flexplate bolts?

[Russell]

The one in my chilton's manual, each to 35 ftlbs

[Destructo]

the flex plate on my truck will wobble some, maybe even up to a 1/2", but if you don't get the torque converter in your tranny all the way it will bend that flex plate when you tighten the bell housing bolts, ask me how I know that .

And I also have never heard of a bent cast iron crank, steel maybe, but I don't think cast iron will bend.

[Russell]

You know what... You're right... There is no way that crank is bent... I can only imagine the forces applied while those pistons whip around at 4000 rpm....

I'm gonna get under the truck and take that plate off again, check it for straightness again, see if the center is bent or something, and make sure that I didn't get some crud between the flexplate and the crank...

[1972C10]

Sometimes its hard to get the flexplate on all the way try cleaning the crank hub with a wire brush Ive gotten aftermarket flexplates that would not fit and i have to massage with a die grinder.

[76cheyenne]

What is the flex plate is it the big gear next to the Torque converter?

[sdkid]

Yes it is. The torque converter bolts to it.

[leastbay]

yeah you might call it a flywheel i called an auto parts store for a flexplate and they said there wasnt one for my truck just flywheels autos have flexplates and manuals have flywheels im not sure really what the difference is though

[sdkid]

A flywheel is much thicker and cast iron instead of steel(read; much heavier)

[76cheyenne]

Ya I always thought it was the flywheel. My Flexplate is rubbing on something and is making a ticking sound. Is there a way to take it out with the engine and the tranny together?

[sdkid]

No, they have to be separated. pull the inspection cover and see if it goes away. Sometimes the cover just needs to be repositioned. I've never seen it in a pickup, but, I have seen flexplates break near the center. Sometimes all the way around.

[1972C10]

Sometimes the dust covers get banged up and get dented into the flexplate. Check for signs of wear and shinniess

[corn]

The first thing Id check is the converter (like Destructo said). The easiest way to make sure you have the converter all the way into the front pump is with the flexplate unbolted to the converter you should be able to slide the converter back & forth away from and toward the flexplate. If its not in all the way it will bow the flexplate.

[dark-star]

very important to make sure the converter is in correctly you can cause some serious damage to the transmission if the pump is not driven by the converter, i have learned the hard way as well!

[76cheyenne]

Oh ok. I already took that dust cover off and it still did it. I see were it is rubbing. The P.O. installed the tranny himself so it is probably installation error. Geesh this truck is full of surprises from the po.