T444E/AT545 Maintenance List and Tips.

Engine, Drive line, and Suspension maintenance list and tips from our school bus conversion. T444E engine with Allison AT-545 Transmission.

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Bus Maintenance can be a bit frightening to some, but it really doesn’t need to be. Here are a few suggestions, tips, and words of wisdom to help get or keep your dream alive and rolling.

Even the most novice of mechanics can learn to service their rig in a very basic way. Filters, Fluids, and the other pieces that keep your engine, transmission and suspension in good working order are really some of the easiest parts to replace.

This post is based on the maintenance we have done on our 2000 International 3800 with a T444E engine and Allison AT-545 Transmission.

Air Filter – Air flow is important to the engine as it is a needed element for combustion as well as being used to cool various fluids as air moves across radiators. The Turbo on the T444E engine also needs air intake to operate. Originally we ordered our air filter through Rock Auto, but the wrong one. No Bueno. We decided after that to order OEM from the dealer. This thing is pretty big. It was $85, but well worth it. The old filter was filthy and covered in dirt, dust, and wasp carcasses. Replacing the filter is as simple as loosening a bolt on the filter box, taking the ring off, removing the old filter element and inserting the new one. Put the ring back on, tighten it all down and you are done.

Oil Filter – Oil is the blood of the engine; it is one of the most important fluids and should be maintained regularly. An oil change is a good idea (and super easy to do) as soon as you get your bus, even if the previous owner says it was just serviced, change it, write down your mileage and keep a watch on your oil level and condition. While the oil itself can be expensive, especially when you have 5 gallons of it to fill, the filters are inexpensive and easy to replace. We are using a Motorcraft FL- 1995 (F4TZ-6731-A) on our bus.

Coolant Filter – Ah the coolant filter… where do I start with thee? After getting a little too warm after a trip to the shop for a ABS sensor issue we decided to replace the filter. Once the old filter was removed we noticed A LOT of rust on and in the filter. We opted to flush the entire coolant system and replace the filter and fluid. We did that just days before making the trip from North Florida to North Georgia. All went well with the temps until we hit downtown Atlanta rush hour traffic. We started getting really hot and had to pull off the highway to let the engine cool down. This ties into the next thing on our list…

Thermostat – After making it to where we were going we determined the
Thermostat was faulty. When we removed the old thermostat there was almost nothing left of it. We sourced the thermostat online as the ones we were getting from Auto Zone and the like were all wrong. After our issues with getting the right parts from the standard auto parts stores we recommend NOT using them, call the dealer or a repair shop and source parts. They will know better what fits and what you need. We were able to find a slightly used one for $35 + 13 for Shipping.

You can see the difference in the picture as to what is supposed to look like next to what we pulled out. The part number I have for this is #NAV1845804C2 or Item # 481828.

Fuel Filter – I just recently replaced this filter on our bus. Without going to the dealer for an OEM replacement we ordered our filter at Autozone by using the filter from a Ford F-250. (I know I just said to not use the auto parts store, but we did, and it took 3 attempts to get the right one, which is why we warn against them.)
The filter we have is Part # FD-4595.

The function of a fuel filter is to strain out dirt and contaminants from engines. If the straining does not occur, the dirt, grim and contaminants can act as a stopper and significantly reduce the amount of flowing fuel into the engine. Reducing the amount of flowing fuel means the engine’s performance is going to decrease until the clog is cleared out of the filter. With diesel engines the fuel is strained and any water that may be in the water is seeped down and released without going into the engine itself.

Before changing the filter you need to turn the small lever on the side of the housing (gold lever in picture)

to release the fuel and water in the bowl and surrounding the filter. Grab something to catch the fluid and DO NOT put it back in the bowl after replacing the filter.

Transmission Filter – The transmission filter we ordered from the dealer. Part # – . It is a good idea with all the other filters being replaced to just go ahead and do this one as well. It also allows you to see the condition of the fluid in the filter and what comes out when you pull the old filter off. If you notice the fluid is darker than normal or see any indication of metal in the fluid I would recommend draining the system and replacing the fluid completely, you may also opt to have the transmission serviced or checked out by a reputable mechanic if you feel the condition warrants further investigation.

Front Shocks – When we bought our bus the previous owner had driven from Mississippi to Florida with a shock that had separated at the bottom mount. I ordered a set of Monroe shocks from Rock Auto. Fairly inexpensive and a simple install. The worst of it is getting the old shock off. If you can, use an pneumatic impact driver to loosen the nuts on top and bottom. We also used a larger pipe wrench to hold the body of the shock in place as we were removing the nuts. The new shocks came with new bushings and nuts. With the shock being broken the driver side tire had worn down pretty badly and needed to be replaced. Tire wear is a big indication that something may be wrong with your shocks as well as other suspension parts.

Front suspension seals and grease fittings – While greasing the suspension I noticed a few seals that needed to be replaced. We ordered OEM seals and installed them ourselves. The lower drag link seal on the door side had been obliterated and needed to be replaced. I also replaced an upper king pin bushing on the driver side.

Greasing the suspension and steering parts is a good idea to ensure they can operate freely and as intended. A grease gun and grease can be purchased rather cheaply at Harbor Freight (that’s where we got ours). One tip is to make sure that the fitting you are putting grease into isn’t actually a fitting to bleed the brakes… I say that from experience. Its a bad idea.

Rear End / Differential Fluid – This is a simple thing to check and fill as well. On the rear transmission housing or differential, between the rear wheels on our bus, there is a ¾ inch nut. Loosen the nut slowly, as the nut gets to the end you may get some fluid that seeps out. That is a good thing. Replace the nut, tighten it down to torque specs and you are done.
However, if you do not get fluid coming out, even when you take the nut off completely, you will want add fluid. Differential fluid is just as important as the transmission fluid so make sure to check them both and fill as necessary. The AT545 is fickle as it is, so lets be good to it and hopefully she will be good to us.

In the end the best thing you can do to keep your rig running right is to perform routine maintenance and the cheapest way to do it is to do it yourself. All of the maintenance we have done has been rather simple but extremely necessary. Remember to take notes on what filters and fluids you use and the intervals you are changing them.

Thanks for reading and if you have any questions or comments please feel free to leave them in the comment box on this post or find us on Instagram and you can connect with us there.

1 comments on “T444E/AT545 Maintenance List and Tips.”

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