I have an 2003 H2 that recently has gone through a major service and now has a slight grinding noise coming from the transmission area, which was not present before.
The engine was removed to be cleaned and to receive new seals, gaskets all around, new plugs, new bearings, a timing chain kit, new oil pump, new pulleys, balancer pretty much everything. Almost everything replaced in the suspension, new water and AC piping as well.
The torque converter and the transmission was never removed. It was sitting for about 2-2.5 months. Other than changing the transmission filter and fluid, nothing else was done to it.
The car is back together now, running and shifting and excellent. Upon cold star there is no noise, but once it warms up there is a slight grinding noise coming from the transmission area. More so from the right side. Not sure what it can be. Already drove about 100 miles since putting everything back together, and the noise seems to be less, but still noticeable.
I uploaded 2 videos to try to demonstrate the noise. The first video (24 sec) is the cold start video, there is no noise. The second video (14 sec) is when it is warm with the noticeable slight grinding noise.
Also uploaded to google photos: https://photos.app.goo.gl/8PyVdvX76MQGG68TA
Is it normal sound? Do you have any idea/suggestion what it may be, what I should check?

Thank you,
Atd

 

Not an expert here... But maybe if there is a Inspection plate on the bottom front of the tranny housing it could be just touching the fly wheel. Happed to a Bud of mine. Only showed up when it got hot and the thin metal inspection plate moved just enough to touch the fly wheel. Don't know if there is on on your rig or not.

Some one with a better understanding of the engine to tranny hook up might jump in and help. My buds happened after a Tranny Rebuild and install.

 

It's hard to isolate the exact sound you're referring to, however could it be related to the A/C?

try tuning it off to see if the sound goes away.

 

Sounds like a loose plate or exhaust rattle of some kind. Check all of the connection points on the exhaust.

 

Hi Everyone,
Thank you very much for your input!
We tried removing the 2 little inspection hole covers from transmission housing. but did not change the noise.
Also tried the AC. We tried running it without the belt on the AC side. It did not change the noise.

Thank you very much for the ideas.

 

Well I would keep at it. Maybe one of those cheap automotivestethoscopesyou can hold and move around the engine compartment .

Here's one on Amazon as the overall pick.

 

A number of years ago I had GM replace my 4l65 in my 06 and when I got it back a few days later I noticed almost that same exact noise. Upon crawling around underneath I discovered when they re-assembled the exhaust the did not fully tighten down the joining clamp.

I unbolted it completely, put some anti-seize on the threads and tightened it up. Noise and problem gone! Had to believe something as simple as that could make it sound like the trans is about to blow up. lol

 

Yeah.. sometimes when your sure it's a little stupid thing and you can see the problem in your brain and say to yourself....I'll fix that tomorrow. Then the next day you crawl under the rig to fix the noise which you were positive was a lose bolt... it turns out you have a big Azz Hole in the Diff....!!!

In your case it was the opposite...a lose bolt on the exhaust flange....LMAO..

 

Update concerning the sounds. We believe we did find the source of the noise. We removed the oil pump and we removed the cover of the oil pump. The gears inside the oil pump was touching the cover and grinding the cover. It was touching enough to make noticeable sound and very slowly grind off the metal. We did not find any metal in the oil, so it must have been very slow grind.
Now we just need to figure out if the pump was faulty, or we did not install the crankshaft socket correctly.

 

Good thing you found it, consider removing the oil filter and cutting it open checking for metal content. If it contains a lot of metal you may want to consider a motor flush after you get it all back together to get all that metal out of it.