Transmission Knock

[cardoff_giant]

Just put a rebuilt 350 and rebuilt 700r4 in my 84 K5. Heard a knock coming from the bell housing. Figured it to be the flywheel but called the transmission shop to check with him. Of course he stated that it must be the flywheel. So I pull the transmission, pull the flywheel and low and behold, there's a crack in it. I put in the brand new flywheel and wouldn't you know it, I still have the exact same knock.

It's most noticable in park and neutral. It decreases, though doesn't go away, when I put it into reverse. This is what first lead me to believe it was the flywheel. I don't hear it running down the road, but the 36" swampers may play a part in that. Anyone run into this before, or have any info for me when I take my beast to the transmission shop and tell them it's their turn to pull it?

 

[GMC500]

it might be the torque converter
I had one failed on 1989 caprice and it was knocking as crazy

 

[scrappyk5]

It is possible something isnt seating right when you are bolting the flexplate and torque converter together. Look and see if the flexplate is cracked again.

 

[gone huntin]

I had a knock from a torque converter too, it did it for a few months......up until it broke the hub inside of it and filled my trans with metal.

 

[USSkoval]

My buddy had a knocking that we thought was coming from the converter, changed it out and sure enough, the knocking was gone.

Also had one hiss really loud while stopped and in gear. Did that for years before it started to finally dirty up the fluid. Anyway, if it starts to hiss too, then you know that's it.

 

[cardoff_giant]

Thanks for the input Gentlemen. I'll mention the torque converter when I finally get it in to the shop.