Allison MH20 & Oil Analysis

[GJH]

Anybody have the guideline on what these should look like? I just talked to Acadian and they don't really have one; other than if iron or silver start escalating. They put much more emphasis on oil pressure as the key indicator. On mine, if I go more than 500 or 600 hours between changes, I start getting an elevated silver, and sometimes iron reading back, but at 150-250 hours they are deemed just fine by PowerTrac (now Stavely Services, BTW). So, the fellow at Acadian said, "well, then change the oild about every 500 hours.."

Just got back another good set of analyses on engines, genset and trannies, even with an unusually-for-me extended (not intentionally) 200 hour interval on the engine oil everything was way within spec, always happy news.

 

[Genesis]

Yep - iron and silver are bad news, and ANY hint of sodium (sea water contamination - bad cooler!) If they're good you're probably fine.

The latter usually will drain the oil (into the water) faster than it shows up in the oil analysis, but.....

 

[mike]

You need to take into account that the starter gear and flywheel starter ring gear are also contained in the same oil and bell housing area, so you can expect to see some iron level increase over time. I would be more concerned if chrome levels increased, as this may indicate signs of early ball and or roller bearing failure.

 

[GJH]

Thanks guys. Pretty much what I thought. I am going to see if someone at the lab can tell me what their thresholds are. They seem to have a couple, one is "Abnormal", a yellow light if you will, where they recommend taking another sample and/or reducing the amount of hours on the sample cycle. I am not sure if or how they take the number of hours on the oil into account. The next level is a red light indicating something is really messed up.

On transmissions, they are particularly focused on silver levels. Everything is hunky-dory for me right now, but I like to compare the results to specs, as I can do with the engines, as well as tracking them over time.