Pro tip: stop using the wrong grease on your fifth wheel plate

I keep seeing guys at the shop grab whatever tube of grease is closest and slap it on the fifth wheel. That's a fast way to have a bad day. Most general purpose greases can't handle the heat and pressure, they just turn to liquid and wash off. I learned this the hard way about six months ago on a Peterbilt 579 that came in with a loud clunking sound. The plate was bone dry and starting to gall. Now I only use a proper fifth wheel grease, the kind with high moly content. It stays put and keeps things quiet. What brand do you guys trust for this job?

2 comments

2 Comments

nathan_moore121d ago

Yeah that clunking sound is the worst. Heard it once on a long haul and pulled over thinking something major broke. Just a dry plate like you said. Switched to a high temp moly grease and never looked back. The cheap stuff is basically throwing money away.

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elliot_allen651d agoMost Upvoted

Totally get where you're coming from, @nathan_moore12, but that clunk can sometimes be more than just a dry plate. On my old truck, that same noise turned out to be a worn center bearing on the driveshaft. The grease helped for a bit, but the real fix was replacing the part. It's easy to blame the lube, but a bad u-joint or a loose yoke will make that sound too. Always worth a second look underneath before just regreasing.