D7-17a recommended fluids

If your climate is moderate use 30W transmission drive train oil for the clutch and transmission and 80-90W gear oil or Cat 50W drive train train oil for the finals. Also 30W TDTO in the steering clutch booster.

I do not mean to hurt anybody’s feelings, but from all the years and hard knocks and mistakes I’ve had with a 17a and a 3t I am telling you 30 wt. in the clutch and booster are fine, for the transmission use no less than 75-90 I run 75-140 synthetic in the transmission works fine and is quiet. This CAT recommendation for 30 wt. was started for the later models with combined master clutch ,transmission and steering clutches using the same oil. As for the finals I just hate to see anybody put 50 wt. in. I was talked into that in 1987 and it COST me a reduction gear and a bull gear and an outboard bearing. Use NO less than 75-140 I run an. Amsoil 250 wt. synthetic it provides a cushion between the gears but doesn’t gel up as bad as mineral oil. If you are dead set on 50wt. At least put some STP along with it.

I agree with you on the oils for your application in ag work which is more steady long strain and higher temps, but for general dozer work the others will be fine. I like Cat's 50W, it clings to gears and is good in 10-20 F degree temps better than other 50W gear oils.

Thanks for both of yours reply that g8ves me a good starting place

75w80 gear oil is very close in actual thickness to 30wt engine oil. but im a firm believer in gear oils in gear cases and engine oil in engines. the oil you want will have cat TO-4 approval for the gear compartments. and you can use a good multigrade diesel oil in the engine a 15w40 is perfect for most applications.

your prefered oil company will have a tech advisory service phone them. or use the product guide on their website or they might have a product selector app.

as for using mineral or synthetic in a machine that is in retirement synthetic is often a waste. but in a machine that is still working for a living synthetic and semi syn oils are a good idea as they handle more extreme operation better.

On the fluids what are the quarts or liters needed in the transmission and the booster and clutch.

Thanks,

GvK