Opinions on oil for HT740

[Seayfam]

Hi all,
I'm in the process of getting my bus all ready for a trip down to Idaho from Alaska this summer. I'm getting ready to change all my fluids and am wondering what you all like running in your 740's.
Also what do you all like using for hub oil?
Thanks in advance

Sent from my GT-I9300

[TomC]

Normal Allison approved ATF. Can run Transynd Castrol synthetic-but you have to change the trans fluid twice to rinse out the standard mineral oil. Transynd is about $40.00/gallon.
Run normal 85W/90 in the hubs. Can run synthetic-but if you have bad seals you'll find out quick with synthetic lube. Good Luck, TomC

[luvrbus]

You can use a C-4 engine oil in the 740, I always used the Cat TO fluid in my 740

good luck

[Seayfam]

That's good, I was really wanting to run synthetic. So you guys don't think running synthetic in an old 740 will hurt anything? Up here I always run TES295 in my Duramax/Allison pickups because it doesn't foam up as bad in the winter. It's the only way I can keep the pickups from bleeding all over the snow in the winter. I can get 10 gal of Castrol TES295 for 500.00 or I can get Amsoil torque drive (TES295 rated) for around 400. Do you guys think Amsoil is as good? I don't drive the bus in the winter, so is it even worth switching over?

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[TomC]

The only approved synthetic by Allison is the Castrol Transynd. Course-there aren't any warranties on old transmissions to worry about. I would not put synthetic in an older transmission-might (and they do) create leaks because of the smaller molecules in the synthetic oil. We don't run that many miles that synthetic is necessary-but-it's your money. Good Luck, TomC

[Don4107]

Longtime trucker brother-in-law swears that the best thing for hubs is 50-50 90w and Power punch. YMMV If you brother-in-law is like mine, would you follow his advice? 

[Eagle]

The Castrol Transynd will drop the temp about 15* and the shifting will improve tremendously.  It did in my 85 Eagle.

[Seayfam]

Longtime trucker brother-in-law swears that the best thing for hubs is 50-50 90w and Power punch. YMMV If you brother-in-law is like mine, would you follow his advice? 

I think we have the same brother-in-laws? Where do you live LOL!
That is the whole point in this thread, I really want to get people's opinions on their experiences and what has worked best for them. I like the idea of the Castrol TES295 running cooler and shifting smoother. I just don't want it to start leaking. My transmission was built in the early 90's and only has 46k on it. If anyone else has had any experience with using synthetic in a older transmission, I'd love to hear your opinions and personal experiences.

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[akroyaleagle]

I have used ATF in my 740 since it was new in 96. Never had any problems.
I like it because I think it is formulated to handle heat better than oil.

I use Lucas hub oil in the hubs. Never had any leaks or problems.

I also use straight Lucas in the diff, drop box and miter box. I just use the called for weights.

I am from Alaska also. Made 27 trips from Anchorage to points south. I Live in South Dakota now.

I think we sometimes over think things.

Course I still change oil in my pickups and cars every 3000 Miles.
I've got a couple with lifetime oil changes and lube programs. They get changed every three months.
Many times they don't have 300 miles since the last change but I payed for 4 changes per year.
Folks say I never check fluids in my vehicles.
I say, why, There's none on the floor of the garage, the pressure is good and they are never low when changed.

Just my way and I'm probably too old and set to change now!

[chessie4905]

I prefer Mobil semifluid synthetic grease in my hubs. When those oil seals finally leak, you'll have oil all over the drum and brake lining, which will cause a lengthening of stopping distance and a heck of a mess to clean up. BTDT. Many of our coaches set for a significant length of time without wheel rotation.