# Differential question??



## NYH1 (Jan 10, 2009)

I have a 2000 Yamaha Big Bear 400 4x4. I'm going to change my front and rear differential fluid. The last time I changed it I went with Yamaha diff fluid. I want to switch to synthetic fluid this time. I plow and haul firewood with it. I don't beat it, I do however work it pretty hard sometimes. 

I was going to use Amsoil Severe Gear 75W-90. I was going to use this for three reasons, 1- I have more then enough left over from my truck, 2- it works with limited slip diff's (my front), 3- I use their 0W-40 synthetic oil and their Superduty oil filter. Amsoil recommends I use their Universal Synthetic Marine Gear Lube because it works good if water gets inside. I've never had any problems with water getting inside my diff's. 

What are you guys/gals using for diff fluid?

Thanks, NYH1.


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## skywagon (Nov 13, 2008)

NYH1;737059 said:


> I have a 2000 Yamaha Big Bear 400 4x4. I'm going to change my front and rear differential fluid. The last time I changed it I went with Yamaha diff fluid. I want to switch to synthetic fluid this time. I plow and haul firewood with it. I don't beat it, I do however work it pretty hard sometimes.
> 
> I was going to use Amsoil Severe Gear 75W-90. I was going to use this for three reasons, 1- I have more then enough left over from my truck, 2- it works with limited slip diff's (my front), 3- I use their 0W-40 synthetic oil and their Superduty oil filter. Amsoil recommends I use their Universal Synthetic Marine Gear Lube because it works good if water gets inside. I've never had any problems with water getting inside my diff's.
> 
> ...


Amsoil severe gear all the way, use it in all my units and have for many years. If you drown the thing you need to change anyway so why use marine gear lube?


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