Transmission noise when hot

[SPO]

Hey everyone so I finally got my rig out for the first time this year, been working on restoration and much needed maintenance over the last 8 months from when I purchased it. I recently had to replace the transmission tower because the linkage on my old one broke causing the truck to get stuck in reverse. While I had the tower off I inspected everything, teeth and gears all looked to be in great shape. Fast forward a week and I took the rig out on a 60+ mile trip, truck ran great and slipped into each gear with ease. When we got home I parked it just to let it idle and flow some air to help it cool down (something I always do with diesels) and I noticed a real loud grinding/rattle from the trans on the driver side so I shut the truck down. The next day I had to mave it and when started it was not making any noise and I moved it around the yard with zero issues. Possibly just low on oil? I did notice the oil was a bit dark but it didn't look horrible. I do have a video of the noise but don't know how to upload it, thanks.

 

[ToddJK]

Hey everyone so I finally got my rig out for the first time this year, been working on restoration and much needed maintenance over the last 8 months from when I purchased it. I recently had to replace the transmission tower because the linkage on my old one broke causing the truck to get stuck in reverse. While I had the tower off I inspected everything, teeth and gears all looked to be in great shape. Fast forward a week and I took the rig out on a 60+ mile trip, truck ran great and slipped into each gear with ease. When we got home I parked it just to let it idle and flow some air to help it cool down (something I always do with diesels) and I noticed a real loud grinding/rattle from the trans on the driver side so I shut the truck down. The next day I had to mave it and when started it was not making any noise and I moved it around the yard with zero issues. Possibly just low on oil? I did notice the oil was a bit dark but it didn't look horrible. I do have a video of the noise but don't know how to upload it, thanks.

You have to upload the video to YouTube then you can share it here, that seems to be the best way.

 

[rustystud]

The next time you take the truck out, and it starts to make this noise again do this check. Make sure the park brake is on. Check your transmission oil level. Then start up your truck.
Push in the clutch and put the transmission in first gear. With the clutch fully depressed, does the noise get louder or changes ? If so than the throw-out bearing is probably going out. If the noise stops , than chances are your transmission input bearing is going bad.

 

[SPO]

The next time you take the truck out, and it starts to make this noise again do this check. Make sure the park brake is on. Check your transmission oil level. Then start up your truck.
Push in the clutch and put the transmission in first gear. With the clutch fully depressed, does the noise get louder or changes ? If so than the throw-out bearing is probably going out. If the noise stops , than chances are your transmission input bearing is going bad.

Thanks for the tip! I went to drain and re-fill the trans fluid yesterday afternoon but did not have the correct size Allen for the drain and fill plugs. Anyone know what size they are?

 

[fsearls92]

If you end up needing a replacement transmission I believe I still have 2 in Las Cruces. Not sure what part of NM you are in.

 

[SPO]

If you end up needing a replacement transmission I believe I still have 2 in Las Cruces. Not sure what part of NM you are in.

I'm west of T or C, I'm interested. How much?

 

[SPO]

Hopefully I figure out most of my issue, I drained and re filled my trans with fresh oil and I was two quarters low and the crap that came out of it was blacker then the motor oil out of my ol 12 valve cummins. It also had a slight milky color so I'm assuming it got some water in it some how. Fingers crossed I don't have any issues but I am definitely interested in a spare transmission to keep on hand!

 

[gringeltaube]

Anyone know what size they are?

9/16"
https://www.steelsoldiers.com/threads/allen-wrench-size-for-trans-fill-drain-plugs.13120/, posts #6 & #7

 

[SPO]

9/16"
https://www.steelsoldiers.com/threads/allen-wrench-size-for-trans-fill-drain-plugs.13120/, posts #6 & #7

Thanks buddy! What I finally ended up doing was digging around in an old bucket of bolts I got and found that a 14mm bolt head fits perfectly in the plug. I guess I got one of the "English" type transmissions that takes the Hex head. Anyway I put two nuts on the bolt and tightened them against each other, put a socket on the nuts and inserted the bolt head into the plugs and it worked as good as any hex head wrench!

 

[cucvmule]

If you have not checked diffs now is the time.