Can some one tell me if i am using the right type of gear oil in my front and rear box 80-90wt hypoid oil. The bike is a 2002 praire 300 4x4. I am confused from reading post some say 10w30 in front and some say 80-90wt?

 

i run 10w-40 in the front
gear oil in the rear
0w-40 weight in the engine.

I run all amsoil synthetic

2008 brute force 750 4x4

 

Ditto.

 

Hayashi...I respect your thoughts here and you've helped me a time or two, but...he is asking about a P300. I think you're thinking about a P360 or P650. This doesn't have a wet brake rear. My factory service manual says 80w or 90w in the rear. (depending on temp.) (Although I have 75w/140 synthetic in both of mine.)

The manual calls for 85w/140 in the front that is suitable for a limited slip differential. (Again i have 75w/140 synthetic in my front differentials too.)

On a side note, the Mobil 424 might be fine though. Guess I'd rather have Mobil 424 in a P300 rear than have 80w/90 in a P650 rear...

 

so i guess 75w90 synthetic would be alright

 

Yes it should be...if it's not too hot outside. I don't know your climate, but if you ride when it's 100 deg plus, it might be a little light for the front diff. Just make sure it is ok for a limited slip (front diff). I'll try to post EXACTLY what it says in the Kawasaki factory service manual tonight. It has what viscosity to use at certain operating temps. Obviously synthetic will give you a little broader range.

 

I put the castrol syntec gear oil in. it says on the bottle. Exceeds the service fill requirements of conventional andl limited slip differentials. If not i will get some synthetic 75-140, and change it again. If you can look at the service manual that would be great.

 

I stand corrected...(slightly anyway)...the manual says: Front GL-5 Hypoid gear oil for LSD, SAE 140, SAE90 or SAE 85w-140. It does not distinguish between temps for the front.

Rear Diff: API GL-5 Hypoid Gear oil SAE 90 above 41 deg. F, SAE 80 below 41 deg. F.

I checked my manual for my Prairie 400 which the exact same diffs front and rear and it said to use SAE 140 or SAE 90w/140 in the front. The rear was identical to the P300.

Obviously your synthetic 75w/90 should be great. I had a bunch of 75w/140 synthetic around here and put it in all my atvs, front and rear. Hope that helps...

 

Thanks for the help. I just had a friend give me some amsoil severe gear 75w-90 to try he said he thinks it is one of the best

 

I'll probably start WW III here by saying this, but I talked at length with an engineer for a large US company that manufactures ring and pinion gear sets. He told me that they tested a bunch of different gear lube brands. He stated that all of the synthetics tested better than all of the dino lubes. He also said that Amsoil was "in the middle of the pack" as far as the synthetics went. He basically said that any synthetics are a great lube for 99% of the general public. Only if you are drag racing with super high horsepower engines (high shock loads) would you ever need to consider (or even notice) the finest synthetic.

I think for an atv it's much more important to change the diff fluid regularly since it's exposed to so much dirt, mud and water...(even though I always use synthetics in everything)