Guys did a 4L80E conversion on my 04 GMC Z71 and need some help. Got everything bolted up today and I'm getting some bad noises. Everything seemed fine until the truck idled for a few minutes. I added fluid and fired her up initially with no strange noises. After a couple minutes I put it in gear and the RPMs dipped and the speedo went up to 20 MPH so I know the pump is working ok (no driveshafts). Put it back in park and a minute or two later started getting this noise. I shut it down and pulled the inspection cover to make sure the converter bolts were still tight. They still seem to be tight. I restarted the truck and the sound was gone but it returned again about 2-3 minutes if idling. This is a vigilante 10.5" converter made for the LS1 style flexplate so I kept my stock 5.3 flexplate. I did shim this converter with washers since it seemed pretty far from the flexplate. I've got at least 1/8" of clearance with the washers now. I wonder if I should take those out? I'm also wondering if I might have got a bum converter from Vigilante?

You guys have any thoughts on this noise? (videos below) Thanks for any input!

 

Did you fill the converter before installing it? How much fluid did you put in the trans before starting it?

 

Yes, I had 3 quarts in the converter and I had added 7 quarts to the trans before I started it up. Good level on the dipstick.

 

Sure sounds like a loose bolt or one that is rubbing the back of the block. I would also look to make sure that the starter is not rubbing the ring gear as it spins.

 

Vince,

Good call on the starter. I'm going to try and get back under the thing tomorrow and do a better job of looking around. I'll definitely check that out. I was pretty beat today after rolling around under the truck all weekend and felt pretty defeated when I heard the racket that I didn't do much investigation.

You think the washers are needed? Do you have a rule of thumb on how much allowable clearance there should be between the flexplate and converter mounting pads?

Thanks for your comments!

 

My thought was a bolt too. Flexplate to converter clearance should be 3/16"

 

Thanks for the comments guys. I looked over everything again tonight and didn't see anything out of the ordinary. The starter has plenty of room and the converter bolts are all tight. I started the truck again tonight and ran for 5-6 minutes and never heard the noise again. I spoke with Vigilante this morning on the phone and they seem to think this is normal clutch chatter for the triple disk. A coworker of mine had one of these on a Trailblazer SS and mentioned having some chatter from his as well.

Anyone else with a 10.5" triple disk that has had any chatter like this? Vigilante has about got me convinced that this is normal under certain light load conditions. I hadn't heard of this until now.

I took measurements tonight for new front and rear driveshafts. I'm going to leave this thing alone for now until I can get my driveshafts bolted in for a road test.

 

Yes I have heard some noise with these converters on the dyno until we would cycle the TCC a few times. I would not say that after a test drive if the thing is still making noise that this is normal. Keep us updated.

 

Also make sure the head of the converter bolts aren't hitting the rear cam cover on the motor.

 

I should have the driveshafts on monday so I'll see how things sound after a road test. Might get on the highway and lock/unlock the converter a few times. If there is something wrong with this converter, I sure hope it doesn't trash this fresh transmission!