Transmission whine

[Kelpiesgmc]

Just had a great little trip in the coach with the newly broken in S&J engine. It had been a long time since I had the coach on the highway. I remember the transmission being kinda loud, but I think it's gotten louder. At around 45mph and above it almost whistles or hums whenever gas is applied. Sound instantly stops when coasting. Should I be concerned?

I checked the fluid and it looked to be correct. It shifts through all the gears like a dream.

 

[pvfjr]

Could it be the final drive? It kinda depends on the pitch of it. I'd check that oil level as well. I added a drain plug on mine so it's easy to let a little oil out check for shavings with a magnetic plug.

 

[Kelpiesgmc]

I dropped the tanks and did some other work on it so it has been a while since I last drove it. Anyway finally got around to looking into this and driving it around again.

The final drive oil was quite low. I put about 1 1/4 bottles in it and that topped it off. It still whines quite a bit starting around 40 MPH. It's screaming by 60 MPH. Sound disappears the moment I take my foot off the gas.

Maybe I should pop the cover off and have a look.

 

[LQQKatJon]

I dropped the tanks and did some other work on it so it has been a while since I last drove it. Anyway finally got around to looking into this and driving it around again.

The final drive oil was quite low. I put about 1 1/4 bottles in it and that topped it off. It still whines quite a bit starting around 40 MPH. It's screaming by 60 MPH. Sound disappears the moment I take my foot off the gas.

Maybe I should pop the cover off and have a look.

My bet would be final drive noise.

Ia it original gearing? You can find used final drives with the original 3.07 pretty easy. Getting one from a car is a good bet.

But a new ratio is always a big upgrade.

Taking the cover off. May or may not indicate a problem. It has to be drastic.

But a failure in a final drive can be catastrophic. I have seen where a final drive bearing goes out and rips off the front of the tranny on a could of coach’s.

 

[tmsnyder]

I dropped the tanks and did some other work on it so it has been a while since I last drove it. Anyway finally got around to looking into this and driving it around again.

The final drive oil was quite low. I put about 1 1/4 bottles in it and that topped it off. It still whines quite a bit starting around 40 MPH. It's screaming by 60 MPH. Sound disappears the moment I take my foot off the gas.

Maybe I should pop the cover off and have a look.

It doesn't take much more oil than that. Sounds like you ran it dry for a while, the damage may be done.

Let me know if you need a 3.07 final drive, I have several planned to drop off with Jeff I in Atlanta to build into 3.70s and LSD but he won't miss it.

 

[Kelpiesgmc]

It doesn't take much more oil than that. Sounds like you ran it dry for a while, the damage may be done.

Let me know if you need a 3.07 final drive, I have several planned to drop off with Jeff I in Atlanta to build into 3.70s and LSD but he won't miss it.

Looks like you're in the north east, it would probably cost a pretty penny to ship one down to southern Arizona?