BGU oil ?

[dewayne 0]

Good morning members, I know that it calls for hydraulic oil for these units. My question is since it is basically a ring and pinion why a 90wgt gear oil wouldn't be better? Just curious. ___________________________________________ dewayne this post can be deleted cause it's in the wrong forum.

[D-17_Dave 12]

While I can't speak for why the enginers chose one type oil over another, you can compare the lubricating properties of the oil and get some idea. Good hydraulic oil being thinner will flow better at a lower temp. and probably dissapate the internal heat better than heavy gear oil. It also has so many new additives that the applied load can't sqeeze the oil film out from between the gears so the gears stay lubricated even though it is a thinner oil. Plus, can you picture trying to get gear oil in those small openings.lol

[UCD 14]

Older style BGB's used 90 wgt gear oil the newer ones are useing ATF. For that matter today they are useing ATF in 4, 5 & 6 speed manual transmissions and 4wd tansfer cases in pickups SUV's and Light trucks. If it will standup in those applications it surely will in a BGB in these tractors.

[dewayne 0]

Thanks for the input, I know it is being widely used in the industry now. Just curious what other members thought. _____________________________________________________________________ dewayne

[HubbardRA 19]

I have rebuilt several 5 speed manual transmissions in recent years. I have been replacing the ATF with a mixture of 25% 80W90 gear oil, and 75% 30Wt motor oil. I started doing this after it was recommended by a friend who has been a transmission rebuilder for 40 years. It is my opinion that an oil designed for lubrication is somewhat better than a hydraulic fluid. How much does it help? I don't know. None of the ones I have done this way have had any problems. As I said, it is just something that I do, I but have no long term data to back it up, and prove whether it is better or worse. I listed this for information only. I am not trying to convince anyone to deviate from factory recommendations.

[dewayne 0]

Thanks Rod for your input. I also put this post under the wrong forum. dewayne

[2burning 1]

If you want some manual transmission oil a little heavier than ATF, there is some stuff called Synchromesh that GM had made. You can get it from GM, Penzoil, and Quaker State. It doesn't have detergent and has an EP additive. The detergent is not so good in a gearbox, as it foams up. But I am no expert on this stuff! I just ran into it trying to find a better fluid for my T5 http://www.pennzoil.com/products/gear_oil/syncro_fluid.html http://www.stealth316.com/2-pennzoil-synchromesh.htm I have synthetic (75/140 I think) GL5 in my BGB's

[Roy 0]

"My question is since it is basically a ring and pinion" The BGB is not a ring and pinion. It has two equal sized spiral bevel gears. Bevel gears have line contact whereas hypoid ring and pinion gears have a wiping/sliding contact which is why they require EP (extreme pressure) additives. The BGB does not require an EP lube. ATF oils/fluids are designed for heat transfer, reduced foam, lubrication, and power transfer (in the torque converter). Not sure why Simplicity switched the BGB's from gear oil to ATF but it probably had to do with reduced operating clearances and/or improved efficiency (lighter oil equals less frictional drag). D-17 correctly pointed out some of the reasons for going to ATF. Enough,