Super UDT vs Sae 80-90wt

JBR · Jun 22, 2004

I'm sure I read in my bx1500 manual, trans fluid "use super UDT or sae 80-90wt gear oil. I'm going to look again but that sounds NUTS. Has anyone else read something like this?

Maxwell · Jun 22, 2004

The manual is talking about the front axle case (at least on the B7500). You can use either gear oil or super UDT. Most Kubota's have super UDT in front axle case because many dealers say that it is just easier. However after reading many discussions on TBN about this subject, I decided to switch to 80-90 weight gear oil at my 50 hour service.

Woodsman_Pete · Jun 22, 2004

I haven't read that but I wouldn't put gear oil into a hydrostatic transmission, I don't think that the gearoil's viscosity is designed to be pumped or filtered, I just read my manual on Saturday and bought 3 Gallons of Super UDT for my 300 hour service on my BX2200, the only place I read to use gear oil was in the gear box of the mower deck and the front axle. I'm just going off of memory on what I read but the Super UDT was $13.75 per gallon and It takes 2.7 Gallons to refill the case after you clean the screen on the 2200. so for $42 bucks I would use the hydraulic oil..

JBR · Jun 22, 2004

I Would never use 80-90wt in a hydraluic system either. I will read the book again and see where it is stated. I remember the guy who droped the bx off, he said to use a good hy-trans in the front diff. I don't like that idea either.

kevinj · Jun 22, 2004

My BX1500 manual states that you may use gear lube in the front axle or super udt. They ship with super udt in the front and trans so why not just replace with proper Kubota fluids. I would not try to save twenty bucks for the maintenance of a $9000.00 tractor. Your dealer should should be able to explain the fluids required to keep your warranty valid.

_RaT_ · Jun 22, 2004

You must not have read the whole thing or missed something. It had to be refering to the front 4Wd axle. The use of gear oil or hydraulic fluid in the front axle is allowed. There is no difference in performance in using either. Gear oil will simply take longer to drain then hydraulic oil. Both are good lubricants. Some are under the impression that the front bevel gears would be better served by gear oil because of "extreme pressure" characteristics it has, but my understanding of this term is that these types of forces on gears are developed at high RPM's, something your front gear case will never see. I use UDT.

uhmgawa · Jun 22, 2004

( Some are under the impression that the front bevel gears would be better served by gear oil because of "extreme pressure" characteristics it has)

I'd have to agree although I'm unsure if any operational benefit exists
in practice. FWIW I have been told by a dealer, Kubota itself sells
Kubota branded 80w90 for exactly this purpose.

To add to the confusion there are those who claim the 80W-90W
gear oil called out in the Kubota service manuals is different from
the 80w90 gear oil sold domestically.

In any case the function of the front axle oil is lubrication. The main
purpose of oil contained in the transmission is power transmission.

Junkman · Jun 22, 2004

The main reason to use Super UDT in the front differential is only applicable in cold weather climates. Super UDT flows better under low temperature extremes, which gear lube doesn't. For the small amount of Super UDT, I would use it in the differential for this reason. The cost differential between the amount of Super UDT and the gear lube is less than a meal at McDonald's!!!!

kevinj · Jun 22, 2004

( For the small amount of Super UDT, I would use it in the differential for this reason. The cost differential between the amount of Super UDT and the gear lube is less than a meal at McDonald's!!!! )

Well stated. /forums/images/graemlins/grin.gif

JBR · Jun 23, 2004

I reread the manual and every one is correct. It only states 80-90 wt for the front diff. I still find it strange that you can use a 10-30 wt hy-trans(super UDT) in place of a 80-90wt gear oil and get the same protection for the bevel gears. /forums/images/graemlins/confused.gif