'98 3.8 GT N/A knock or lifter after tranny rebuild

After spending 3 months diagnosing a stupid distributor cap on my van (see Chevy posts) and rebuilding my daughter's Grand Prix tranny (4T65E), I'm down to yet another puzzling problem.

The original problem:
GT 3.8 with the 4T65E tranny just disconnected while stop and go in construction. Pump was replaced before because a hand written price was on it. This time, the pump's vanes were chewed about 1/8" down, the pump rod was twisted and broken off in the torque converter and the 4th clutch hub (original prob) had sharpened splines into it's sun gear. Replaced hub, some washers, rebuild kit, plus shift pressure modulator valve and torque converter, etc.

Get the tranny back in and while filling, I started it while low on P/S fluid. Lots of whine, but finished filling the tranny. Test drive and all is fine. Very pleased with the shifting and T/C lockup including downshifts. Topped off P/S fluid and the whine turned into a whine/squeal/tick. While listening around, it dies real quick like something locked up. Cranks sluggish but starts up and idles. Tick getting louder and more solid now and whine easing off some. Stethascope can hear the tick at the tranny, but it's louder on the block... still louder on the intake and very loud on a rocker arm through the oil filler hole in the valve cover. It pretty closely resembles the tick of a lifter, but it's almost too hard to be that. It's mostly like a rod knock now with a little 'tinny-ness' to it. P/S whine mostly gone (probably purges the air bubbles by now). Problem is that it ran last night for about 30 seconds before seemingly 'seizing' up and dying on me. Restarting still cranks hard (dims the headlights) but starts anyway. After that, it barely idles and dies if you don't feather the throttle. Seems very labored to run and the knock now has almost a squeal (like a belt squeal, but shorter, louder and heavier) sound that goes along with it.

I did have some problems putting the guts back in the tranny, but after learning how, I got it to slide together nicely with no questionables. (I haven't rebuilt a tranny in 10 years, but I've done dozens in the 80's).

Any ideas out there? All I can think of is that while sitting with the hood open to accomodate the engine hanger, maybe something got in the engine (it was still closed up) and she spun a cam bearing. Beyond that, I can't think of anything that could make those sounds. One would think that the tranny was the problem though with 4 miles on a non-professional rebuild, but the sound is definitely strong around the valve train.

Help! My daughter's ready to have my hide after spending 3 months getting the tranny done!

Any way we could get a video of the noise maybe on youtube?

I have had cars (motors) sit for a few months while I work on them, and sometimes (one in particular sat all summer) when they were first started, the lifters ticked untill they got pumped back up.

Otherwise, you say you left the hood open? How could something fall inside the motor? Did you have the valve cover or oil cap off?

I would be half tempted to take the plugs out and see if one has any mechanical damage. Then you could do a cylinder drop test to try and narrow down and see if the tick changes when a specific cylinder is cancelled.

This is an interetsing one....

I would pull off the accessory drive belt and start it up again. I bet either an idler pulley or one of the functional units (e.g. PS pump, alternator, AC compressor, water pump) has locked up a bearing. The "tick" is from one or more balls floating around between the races as one of them may have disintegrated to dust.

Don't run too long because there's no water pumping but you can get away with enough idle to check if the symptoms are gone.

Even if the above doesn't resolve the issue you still have at least eliminated a lot of hardware with a simple stroke as you troubleshoot.

I haven't been able to get out there much in the last couple days, but I did get to check two more things. I pulled the belt and started it up. It only took 2 seconds to know that wasn't it. I also drained enough oil to check for water in the oil. In talking to the guy who works exclusively on these trannies, he said these engines are notorious for blowing a gasket in an intake water jacket after overheating, revving (from bad tranny) or even sitting long term. According to him, they can dump water directly into an intake runner and/or the crankcase. This could cause hydro-locking, knocking, bearing seizing and possibly even lifter collapses. I didn't see any water however.

Another suggestion has been to check the flex plate for cracks. Since the pump shaft twisted off in the torque converter, the shaft may have pushed the flex plate toward the block and cracked it. He said that this could make most of the sounds and would likely get worse quickly. I'll have to wait til tonight or tomorrow to get under there to see. I hope this is it since I won't have to go deep into the engine or transmission. :licka: I'm kind of doubting it, since the sound sounds loudest inside the valve cover, but who knows.

Oh, and I haven't done a cyl drop-out test yet or pulled the plugs. We'll see how the above goes. It's too bad my iPhone doesn't do video, but I'll see if there's a way to send an audio recording.

....It's too bad my iPhone doesn't do video, but I'll see if there's a way to send an audio recording.

Dang! Those things wont record video? I thought they did everything! Heck, even my frebie upgrade verizon phone can take pictures, record sound and video. :icon16:

I have one of the old iPhones before they added video, but I do have a sound recording app. I converted it to mp3, but I don't have any way to post it here. How best to send? (Email is easiest)

I pulled the belt and torque converter off and the sound is still there. Pulled the front valve cover and it's louder but I don't see anything out of the ordinary. So I enlisted another nephew and we started pulling the engine. Should have it out and apart this afternoon if we can find a cherry picker to borrow.

Once it is out, what are you going to do? Rebuild it? Did you pull the plugs to check for mechanical damage?

Can't scrounge up a cherry picker just yet so it's sitting in the driveway waiting for it to snow. :uhoh: I just hope the weather cooperates for me to get it out and into the garage. There's not enough room in there for the car and the engine hoist.

I pulled 2 plugs and didn't find anything wrong. I also drained a little oil and didn't find any water. I'm fairly convinced there's a rod or bearing gone south in the bottom end so I'll have to at least put rings and bearing in it. ...now who did I last lend my cyl bore mic to?... Can't believe I'm gonna do this on a little V6 with 206K miles on it!

What was the coolant level at? I wonder if the UIM picked that exact second to flood a cylinder with coolant and hydrolock the motor. Try pulling plugs 5 and 6 and see if they look wet with coolant.

Pulled 1, 3 and 5 and no problem found. Rolled the engine and nothing (like water or fuel) came out. Drained a little oil and got no water there either and the coolant level is completely full.

Just got word that we've got an engine hoist rounded up... and 4" of snow. Feeling kind of mixed on the latest news.

So, how can I post an mp3 file for you fine fellows to hear?

Ya know...after more thought...I hate to bring up this possibility as far as you've gone.

I'm wondering if one of the hydraulic lifters simply drained down and hasn't refilled with oil again. That would fit with why the noise mysteriously started without you doing anything other than having the car sit for awhile.

It would probably take either an extended idle to get everything good and warm, or just some easy driving, there should be no damage to the lifter until it pumps back up unless you're doing WOT runs around the block the whole time ;)

Thanks for the comment... Both to you and to everyone above.

I considered the lifters. Since the odd bank seemed a little louder, I pulled that valve cover. All rockers act the same and have no play. Tapping on a screwdriver on each end of each rocker gives the same bounce and sound as each other one so at least that bank is "uniform". :O And the noise sounds much deeper/thicker/heavier than a lifter now. It also gets worse as it warms up (over the course of 10-20 seconds).

I did record a sound and have an mp3 file but I don't know how to 'post' it so you guys can hear it. You can pretty much seperate it from a lifter sound in the file.

What about a leaking exhaust manifold?

What about a leaking exhaust manifold?

that was actually my thought too.

To share files I used to use www.box.net It used to be free, but might not be anymore. Basically you have to sign up, upload your file, select it to that its open access to share, and then post the link to it here so we can download it.