To gillig phantom or not to gillig phantom, that is the question

[jamesd20]

im going to test drive it again tomorrow

[jamesd20]

it seems it has an Allison HT-747 (4 Speed) transmission, is this a good one?
also according to the VIN it is a 1984 bus rather than a 1990

[cadillackid]

Did you check trans fluid level after it warned s bit? ( check while running).
And also color. If it’s dark brown or black I’d run.
It may be honey colored as Allison recommended engine oil in those for severe duty service.

Does it stay in reverse or does it disengage and just rev when trying to go forward?

Low fluiid makes R to D changes lazy but staying in R could mean stuck solenoids / very dirty fluid..

A misadusted shift linkage you would notice that the gears didn’t feel in the right place.. ie shifting to N might put you in R and going to R might feel sloppy on the handle

The Allison 700s were the choice for the heavier busses but like anything they can wear out or break.

My first step would be warm it up a bit, run the shifter through all gears then back to N and check the fluid. It should be a little over the full cold mark. If you test drive it on the road 15 or 20 minutes it will be likely closer but still a little below full hot mark.

Christopher

[jamesd20]

I'm going to check it today

It would stay in reverse and I could drive it in reverse it it wouldn't just rev

It may be operator error because I just read a service manual that says it must be shifted into neutral before shifting into any other gear and I didn't do that I shifted it directly into reverse and directly into drive so hopefully that's all the problem was

[Iceni John]

Originally Posted by jamesd20

it seems it has an Allison HT-747 (4 Speed) transmission, is this a good one?
also according to the VIN it is a 1984 bus rather than a 1990

Your photo of the engine clearly shows that it has a DDEC computer on it. DDEC I was not introduced by Detroit until the mid-1980s, and DDEC II (which is what it looks like to me) was introduced in the late-1980s: I have DDEC II in my 1990 bus. You therefore either have a repowered bus, or the VIN is wrong. Whatever it is, it is not a 1984 MUI engine!

John

[cadillackid]

Wasn’t it pretty common to do repower on these? From what I was told is ddec ii offered better mpg and power than the mechanical predecessors?

[Iceni John]

Originally Posted by cadillackid

Wasn’t it pretty common to do repower on these? From what I was told is ddec ii offered better mpg and power than the mechanical predecessors?

There's still plenty of MUI Detroits giving good service, so simple age is not the only cause for a repower. There's any number of reasons why a new engine could be needed (but many of them stem from driver stupidity and incompetence), but who cares, this bus has a newer engine than it "should" have. DDEC will give another half to one MPG over a MUI engine, will run cleaner, won't ever need racks run or governors readjusted, and can give you a wealth of diagnostic information if things go tits up (as long as you have a Pro-Link or DDR scanner). Power won't necessarily be greater than a MUI with similar-size injectors, and torque rise is dependent on turbo A/R and other factors, so don't expect a DDEC to outperform a MUI. Some folk, usually the die-hard traditionalists, are scared of electronics, but as long as you keep all the electrics in good condition and can read the DDEC Troubleshooting Manual and simple schematics, you'll be fine. After initial trepidation with mine, I now have no qualms about it, and I'm glad to have the ability to know exactly what the engine's doing through my Pro-Link. DDEC II, even though it's now been superseded by many later iterations, is still a good system - don't be intimidated by it!

John

[cadillackid]

I think most know how I feel about electronics .. plus there is a ton of stuff published about DDEC since it was used in so many vehicles. I know 3 and 4 were standard J-1708 which lots of scam tools exist for. I dont now a lot about 2.

Of course if it is a repower then you always hope it was done correctly.
Christopher

[jamesd20]

We bought the bus and plan to start conversion next week!

[BlackJohn]

Congrats, that is what I was wishing you would do. Take good care of her and she will do likewise for you.
That is beast material!



John

[TJones]

Nice looking bus! The valve cover looks to clean to be a Detroit! Looking forward to more details and pictures.

Ted

[cadillackid]

congrats on your new bus!!!!

-Christopher

[Tango]

Clean valve cover on a Detroit? That's as rare as a Harley that doesn't leak.

[EastCoastCB]

Originally Posted by Tango

Clean valve cover on a Detroit? That's as rare as a Harley that doesn't leak.

Detroits, Harleys, and VW's mark their spot!

[BlackJohn]

So did they come down or did you pay full price?

Where did you find this bus, any more pics? And the tranny issue, what did you find out?
Just being nosey for the benefit of all,


John

[jamesd20]

It needs new batteries and new tyres but when it's jumped it fires up right away and purrs along

[Robert Tassi]

Gillig is a great bus, though I have no experience with that particular transit model. The engine looks very clean ... Detroit's are great engines ... must not be lugged ... What type of service was it in?

[jamesd20]

It was an emergency mobile command centre. Do I need to worry about lugging it if it's an automatic?

[kenny76]

I'm curiously looking for a new bus to convert. I considered a transit bus and often wondered how well it would do with the task. I was swayed when I bought my skoolie away from one that was up for grabs because everyone said it would not do well on the highway. What kind of speeds are you able to achieve? What about fuel economy? Currently my skoolies gets about 11.5 to 12 mpg and tops at 61 mph. This top speed is why I'm considering either a mci coach or a transit bus.

[cadillackid]

You can build your Skoolie to achieve better highway speeds .. swapping gears , transmissions, upping the horsepower etc.. if your bus is already converted then it might be more feasible than starting over with a different bus.
If it’s not a far along project then finding a different bus makes sense. There are highway capable school busses too. A lot of the western states in the Rockies have rear engine units designed for highway travels .. you find them in other areas of the country as well , if a bus is from a manufacturer still in business you may be able to call a dealer with the vin and ask about engine trans horsepower gears etc.

A bus limited to 61 can be limited by mechanics or electronics. If it’s sinply computer limited a trip to the dealer or a friend that has the software can remove the limiter . That obviously doesn’t work if the mechanicals don’t support higher speed
Christopher