I wasn't going to post here about this but Cliff started the discussion on my Facebook page so I thought I'd ask around here. Yesterday we were driving the coach up the very steep grade of the Park Vista Doubletree Hilton here in Gatlinburg TN. She couldn't make it up so we unhooked the 7,000 on land cruiser. She still couldn't go at full throttle she was just sitting there. So I backed down the hill gave it a small amount of a running start and made it to the last steep curve near the top. She pooped out and actually started rolling backwards under full throttle. This caused the tow hitch to jam into the pavement behind me on the curve. I was now fully stuck. Couldn't go backward and certainly couldn't go forward. I blocked traffic for an hour while figuring out what to do. A tow truck wouldn't even be able to get past me to tow me up, I had no way of reversing since the pavement behind me on the curve rose up and it would just keep wedging the hitch into the pavement. So I drove the Land Cruiser to the front of the bus, chained it to the tow loops on the front of the coach and to my frame tow points on the Cruiser. I have triple lockers so I put the Cruiser transfer case into Low gear, actuated all diff locks, and had my wife tow the bus up the hill while I drove the coach giving it throttle behind her all the way up. She spun all four tires for a moment until we got the coach unstuck from the pavement but after that we walked up that hill like it wasn't there.
So here's the question:
My coach was rated at 400hp and we did give it a little bump recently via computer and someone who knows their stuff. But it should have more low end. My 6v92 bus got up that same grade last year. Is the gearing in the rear end of a 102C3 8v92 different than a 9 with a 6v92? Or do I need to turn up the fuel down low in the RPM range or something? Here's a photo of heather towing me:
(https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Fuploads.tapatalk-cdn.com%2F20160909%2F57f0cc998646d6a9ca0051edbdfa9ceb.jpg&hash=937fe1f134b3685c230a0720d48023ea07086c4e)
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Scott gear ratio varies bus to bus not by model!
A good way to know if you have a different ratio or not is by seeing what the "top end" is on the highway!
Or check tags on the differential (if there still is one)
But that bus should have made it up that hill (maybe screaming and kicking the whole way, but still should have made it)
I have been up that hill many times (about 2-5 times a year for the last 10 yrs) in many different buses! And even in snow as one of the times I go is in February every year!
Yes I've had exciting moments like breaking traction in that last turn adn smoking the tires on the bus for a second or 2-3!
So it sounds like the DDEC needs some more tuning!
Don't know who did it for you before, but I do know Ken Arnold aka Hard headed Ken here on the board is pretty darn good with them!
The DDEC needs to sense turbo boost to supply the fuel needed to make power, could be something simple like a hose bad on the sensor, sensor, manifold leaking or a communication problem it won't be the gearing the bus will pull the hill lol been over it before with a 8v71 and 3:73 gear towing a Jeep
Your fuel filters aren't in need of changing are they? They can get plugged up at most inopportune time, even new ones. Were you seeing any smoke from tail pipe? Torque converter should have allowed it to keep rpms up. Not stuck in second gear; gov issue? Boost and fuel pressure gauges would be of benefit in these situations. Having a toad with 4wd can sure be helpful in a situation like this.
Was this problem before or after the oil leak at the blower housing? They might be related.
I forgot what transmission he has but he could have a 2nd gear start
Do you have a tachometer on the bus? What was the stall rpm when you were trying to pull the hill? Should be around 1500. Maybe a bad torque converter. Good Luck, TomC
If second gear start, should go to first if pulled down to "1" on the shifter. Good Luck, TomC
On my bus with 4.56 rears, and V730, my overall starting ration with torque converter (2.5:1) is 21.432:1. Even with 3.08 rear end on your bus, with the HT 740 or HT754CR (both same starting gear) you have 3.692 1st and with 2:1 torque converter, you should have a starting overall ratio of 22.74:1. I have never gotton stuck, and I weigh 31,000lbs with 375hp. You should not have gotton stuck, even with it at 400hp. I think you were stuck in second. Good Luck, TomC
Quote from: TomC on September 09, 2016, 08:34:26 AM
If second gear start, should go to first if pulled down to "1" on the shifter. Good Luck, TomC
Sometimes they will lock 1st gear out on the electronic Allison's,a trash hauler here has his locked out because the drivers would destroy his drive trains about 1 a month
I think you had some problems when you first got the coach. This might be some of the same problem. My 102C3 with the same engine and transmission had a 3.36 rear and would pull any hill any where. If you ever have the problem with pulling, put someone in the car and let them help push. That has worked for lots of us in the past. If you don't have one the silverleaf would be a good investment. With one you could see where you are down in power. No boost no power!!!
Jack
Scott:I have the same problem with my bus.Got plenty of power when out and running,plenty of power in reverse ,but really drags it's heals on take off.Haven't gotten stuck yet but am afraid to bring it home and put it in my parking space in my yard out of fear that it won't pull back up out of there.Pulling in is not an option.Guess we'll have to start dong like the fire departments done with their old gravity fed engines,when they came to a steep hill,they turned around and backed up them. Incidentally, mine has the ht755cr which I am finding out is a quirky rascal!!
what does the transmission fluid smell like now...?
I still believe he has boost problem though
Quote from: luvrbus on September 09, 2016, 12:01:52 PM
I still believe he has boost problem though
i do too...but the nose knows :(
it may be (or has become) a compounded problem ... :( :(
Tranny fluid will be checked tomorrow. My
Prior check was that it was completely
Fine and clean. I have no idea the rpm but it was plenty high. I have the Allison 748 and the push button was selected on "1". Not much black smoke at all coming out of the tail pipe. Just changed fuel filters. Silverleaf coming soon.
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Trans fluid check this morning looks great. Fluid is nice and red and clean and smells like nothing...mildly like trans fluid. No burnt smell whatsoever. I have burned a couple of trannies in my lifetime so I'm familiar with "toasted trans" fragrance. I will need to sort out why I'm not getting enough low end grunt. Again, my highway experience is pleasant. Coach scoots along really nicely even up grades etc. but it didn't even want to attempt this hill. My old mci 9 with the slow 6v92 did this hill so I need to rectify whatever my issue is.
1. Going to just go ahead and put fresh fuel filters in
2. Have the computer looked at for codes and check fuel tables/boost etc.
3. Silverleaf will be ordered tomorrow. Been wanting to throw my dash instruments away any way. I'll keep oil pressure and water temp just for a backup tho.
4. Continue to drive it and enjoy it. This is our first tour with the coach and so far we are loving it. Baselining it is always a little bit of a process knowing what's normal and what isn't on a new to us coach. But so far so good. (https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Fuploads.tapatalk-cdn.com%2F20160911%2Fb84e5e13ca2acb47f4f6dce7a7a6b065.jpg&hash=6200bc2a41529bd4678ab52841b06645dd037ffe)
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I have been up that hill with my first coach which had an 8V92. It is steep but no worse than my 29 to 34% driveway.
I read all the posts and unless you have information that has not come out it does sound like a boost problem as Clifford points out. When you were coming up the grade what boost were you getting? What were your RPM's?
A turbo boost sensor that is going bad, or one that has a leak in the little section of hose leading to it can limit the amount of boost the engine sees and these coaches are gutless when that happens.
Quote from: bigred on September 09, 2016, 11:01:43 AM
Scott:I have the same problem with my bus.Got plenty of power when out and running,plenty of power in reverse ,but really drags it's heals on take off.Haven't gotten stuck yet but am afraid to bring it home and put it in my parking space in my yard out of fear that it won't pull back up out of there.Pulling in is not an option.Guess we'll have to start dong like the fire departments done with their old gravity fed engines,when they came to a steep hill,they turned around and backed up them. Incidentally, mine has the ht755cr which I am finding out is a quirky rascal!!
What kind of quirks have you had with that HT755CR?? Mine, with a 8V92TA, takes off like a dragster. Tow a Ford Supercrew and it still does. 3.58 rear end ratio.
Good to see you ordered the Silverleaf. I think you will be driving at night some, so you will want to not have too much light from your screen on the dash. I put darker colors in the gauges and made the type yellow. The first time I tried to drive at night with the white gauges had to turn it off.
Jack
Muldoonman: The only two quirks I have had with my HT755CR is that it acts like it takes of in second gear.Plenty of power in reverse and and running ,just slow take off's.The other one ,it occasionally refuses to go in gear after being parked for a fairly long period.When this happens ,I turn the switch off and back on and that seems to get it going .Stores no codes when this happens.
AHHH-nothing like the good old mechanical HT740. Just saw a video of the Freightliner Bonneville racer with a 16V-92TA with 4 turbos putting out well over 3000hp. Transmission-HT740! Good Luck, TomC
Quote from: TomC on September 12, 2016, 09:25:41 AM
AHHH-nothing like the good old mechanical HT740. Just saw a video of the Freightliner Bonneville racer with a 16V-92TA with 4 turbos putting out well over 3000hp. Transmission-HT740! Good Luck, TomC
And to think that Allison considers it to be obsolete! It is one of the best ever made. :)