International S1700 6.9 Diesel Info Needed Please

woodyking · 03-23-2008, 06:10 PM

We just bought an Air Force bus, 1987 year model. I've been trying to find out stuff like what oil to use, what transmission fluid, etc. No luck, though lots of truck people are quick to say it "probably" uses this or that. The original paperwork on the build of it states engine 6.9, transmission A. It is a four speed automatic, I suppose Allison from the A, but not sure. I tried local Advance Auto parts, but their books don't include heavy trucks at all. I did get an oil filter at WalMart from their book, but nowhere can I find exactly what oil to use. It has four spin on filters, one below which I know is oil, then one on top of the engine itself that is the diesel fuel filter, and the other two I'm not sure of yet. I tried following pipes some and believe the one near the top of the radiator is for the transmission. That leaves the last one, also by the radiator but very low. Unknown as yet what for... We have been hard at getting the seats out, scrubbing the mildew from the walls, ceiling, etc.
Is there someone on here with this type bus? It was made by Amtran in Arkansas, 1987, International engine and four speed auto tranny. I can't find anything on Allisons' site as to how to tell what tranny is what, or even what fluid to use. I've got a big folder on its past maintaince, all done by base mechanics, but nowhere does it say what they used. And nothing is marked on the reservoirs like most military stuff.
Any help greatly appreciated, it is going to be our "motorhome" within a few months if all goes well. Last year we made a sweet little houseboat, so this will be our second "live-aboard" project. Thanks again for any info! Woody and Linda, in Georgia!

lapeer20m · 03-23-2008, 11:35 PM

lots of diesels have two oil filters. some of them use an engine coolant filter (prob more vehicles should have that!) I haven't seen a spin on trans filter, but it's certianly possible. The transmission cooler lines run up to the front of the bus. If you can read the filter it should say what it is deiged for. You should also be able to follow the lines to/from the housing and get a good idea what it's filtering. Lastly, you can always remove the filter and see what's inside.

that's an international motor same one they used in the ford pickup trucks prior to the 7.3 liter.

rotella T 15/40 oil is rated to be used in pretty much every diesel engine. it's available at wal-mart autozone etc.

someone who knows Allison's will chime in with what kind of atf to use....i think it's a pretty versatile transmission when it comes to fluid.

the angle grinder is your friend when it comes to removing seats. first trying an air or electric impact wrench from underneath after spraying wd40 on the bolts and someone on top holing a wrench is a good idea. Bolts that will come out or break are faster to remove than grinding. Wear safety glasses!

woodyking · 03-24-2008, 05:32 AM

Thanks, I was lucky on the seats, most of the bolts weren't too bad rusted, and the legs to the floor were held with lag screws, which mostly rung off with an air rachet. If I get home today in time I'm going to try to follow fluid lines to the odd filters. Any transmission info still needed bad. I got the Rotella oil, not sure yet what the capacity is but will have an idea when I drain her.... She only has 60K miles, so there has been alot of time sitting. Thanks again, Woody

wmah · 03-24-2008, 02:24 PM

my bus with a 7.3, has two spin on fuel filters one oil filter and a spin on transmission filter under the bus driver side near the transmission. And then most of the other filters that a car would have. My bus doesn't have a antifreeze filter.

woodyking · 03-24-2008, 03:27 PM

Mine doesn't have a filter on the side of the tranny, like I've seen in some pictures. It may be an older model than yours, or maybe because it is military. Sometimes the military orders stuff done weird. I believe the 7.3 came after the 6.9, so your engine is newer for sure. I'm doing some hard looking tonight for any numbers I can find. Thanks alot, I'll let yall know what I find out no matter what! Woody

woodyking · 03-25-2008, 10:40 AM

Turns out that my tranny is an Allison 545. Now, on Alllisons site, they say all the C4 fluids are no longer recommended, but don't say what is........ What are you guys using? Dextron III shoud work, but in some cases especially with this older tranny, what would be best? Lots are running the 15/40 engine oil I believe, but that seems like it would be thicker than DextronIII.... How can something so common be such a mystery that even Allison can't explain? Recommendations welcome, experience with what you have used successfully I'd love to hear. Thanks very much for all help, Woody

woodyking · 03-31-2008, 06:56 AM

Moving right along, I have two fuel filters, one mounted on the right radiator post, and one on top of the engine itself. And a transmission filter below it on the frame. It has redish fluid which I believe is Dextron III in it now, so I will go with that. I changed the oil, used Shell Rotella 15W40 like most truckers use on the big rigs. This particular engine/pan holds 16 quarts including the filter. Running great. Now on to the project! Thanks for all the advise I got, Woody

Elliot Naess · 03-31-2008, 02:31 PM

I've been out of town and just found your inquiry.

Shell Rotella T diesel engine motor oil... Yes. Any brand is fine, so long as it is oil for DIESEL engines. 15-40 weight is very common, so you cannot possibly go wrong with that.

Dexron type ATF for your Allison AT545... Yes.

For some years, it was somewhat common to use a very specific type of motor oil (probably what you have seen referred to as C4 -- my memory is a bit rusty) in these trannies, but as you have discovered, that practice has been discredited. The idea was to reduce slippage, but a bus mechanic told me that the motor oil often gummed up and caused other problems instead.

My (former) S1700 had a spin-on transmission filter on the frame at the right front, near the radiator, so that may not be unusual. Sounds like you have this pretty well figured out now.

Oh... Welcome aboard! Your Air Force bus very likely has a higher roof than most school buses, so you are now the envy of most of us!

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