Drivetrain whine - FG434 + Entertaining Pics

Have had phantom issues before in various vehicles, sometimes the only cost effective time and monetary solution is to wait unit true problem manifests itself and hope it does not cause residual issues or break down at a very inconvenient time.
This is where being a conscientious vehicle owner can bite you in the butt, my wife would not notice that problem and not worry about it and just fix it when she has to. Where it would drive me nuts trying to find it and in the end I would have spent more money and time than her trying to be proactive.
 

yabanja

Explorer
As stated before, drain fluids from all boxes/axles and inspect for bearing material. I found that my truck was significantly quieter after switching to Redline fully synthetic fluids in the appropriate weights(except the rear diff which I run conventional with lots of friction modifier for the lsd)

Good luck!

Allan
 

Spoony

Member
Just an update for those that helped out.

I dropped all drive train fluids (again haha) and went with Gulf Western (Australian) full Synthetic 80w90LS across all components (talked to their tech department first to confirm suitability). I can confirm that running 80w140 does impact performance, probably most noticeable because has so little power already. More interesting is the noise behaviour. The whine is still there but peak volume reduced. It however more consistant, so the whine is there when it's cold or when it's been driving for 6 hour straight, the difference in volume when hot is more but only marginal. With 80w140 it is not as loud when cold but gets as loud when hot, probably louder. With the old semi synth 75w90 Penrite it got louder when hot.

This tells me that properties of the new oil are pretty consistent across temperate grades, where as the previous fluids, especially the 80-140w mineral is in't. So vs all previous fluids it seems like the oil is maybe moving better when cold but staying together better when hot. Based on at least the behaviour in my truck I'd recommend running this throughout the drive train.

They'll also deliver if you contact and find the local rep. 20l for this fluid and 20l of their semi synth engine oil, delivered for about $220 AUD, I probably wasted more than that stuffing around with other fluids haha.

Probably not much help to those out of Australia though, but a Allan stated above it seems running a full Synth is a good thing.
 
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