Bus Conversions dot Com Bulletin Board
September 19, 2014, 10:59:36 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
News: If you had an E-Mag Subscription: It takes up much less space in your bus.
   Home   Help Forum Rules Search Calendar Login Register BCM Home Page Contact BCM  
Pages: 1 2 [All]   Go Down
  Print  
Author Topic: Allison Troubles  (Read 3955 times)
homermandy
Jr. Member
**
Offline Offline

Posts: 85




Ignore
« on: June 19, 2006, 05:24:04 AM »

Allison HT-746 automatic in my Eagle 15. Cruising on highway for about 10 minutes, DO NOT SHIFT light goes on. Pull off on next exit, torque converter does not unlock. I stall the engine, check fluid, 4 qts too low. Start the engine up, take off, and the light comes back on and stays in whatever gear it was in last. However, it does not stall and torque converter unlocks. I am taking to service tomorrow. Just wanted to know if anyone had any clues. Engine is rebuilt < 1000 miles 6V92T. Thanks
Logged

1991 Eagle 15
TomC
Hero Member
*****
Offline Offline

Posts: 6783





Ignore
« Reply #1 on: June 19, 2006, 07:27:11 AM »

First off-did you top off the trans fluid? Bus trannies have shallower pans for better ground clearance and 4 quarts low may be enough to start making the trans do weird stuff.  Try that first.  Good Luck, TomC
Logged

Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Busted Knuckle
Hero Member
*****
Offline Offline

Posts: 6447


6 Setras, 2 MCIs, and 1 Dina. Just buses ;D


WWW

Ignore
« Reply #2 on: June 19, 2006, 10:20:55 AM »

First thing I'd do is change the fluid and filter if it was that low, it's been pretty hot and probably burnt! If that doesn't help it I'd check with an Allison qualified repair shop!  FWIW BK
Logged

Busted Knuckle aka Bryce Gaston
KY Lakeside Travel's Busted Knuckle Garage
Huntingdon, TN 12 minutes N of I-40 @ exit 108
www.kylakesidetravel.net

Grin Keep SMILING it makes people wonder what yer up to! Grin (at least thats what momma always told me! Grin)
Sammy
Hero Member
*****
Offline Offline

Posts: 523




Ignore
« Reply #3 on: June 19, 2006, 02:03:19 PM »

See if you can flash out the trouble code, might be a 51 - lockup solenoid.
Let us know what code you get, might be able to help a bit.
Sammy  Cool
Logged
homermandy
Jr. Member
**
Offline Offline

Posts: 85




Ignore
« Reply #4 on: June 19, 2006, 02:16:41 PM »

Took it to local Detroit service center tonight. Dropped it off. Light didn't come on for a 30 minute ride. I suspect oil too low causing weird things to happen? They are going to run the coach with the Allison computer hooked up to it to check shift points, etc.  I just had a rebuild on the 6V92T and i notice excessive smoking when the trans downshifts. They are doing a few more tests on the fuel pressure, etc. I will keep you posted. Thanks
Logged

1991 Eagle 15
homermandy
Jr. Member
**
Offline Offline

Posts: 85




Ignore
« Reply #5 on: June 22, 2006, 04:57:20 AM »

Update:
 They are still trying to locate the software for the HT746(scares me).  I am picking it up tonight regardless.  Strange thing is that when they test drove it, it would only go in re reverse and stayed in 1st gear. It would not shift. I am wondering if the Throttle Position Sensor might have something to do with it. OR a bad connection somewhere. It rode too good when I dropped it off for the 30 minute ride. Any suggestions? When I get it home tonight, limping in 1st maybe, where is the TPS located on the 746? Thanks
Logged

1991 Eagle 15
homermandy
Jr. Member
**
Offline Offline

Posts: 85




Ignore
« Reply #6 on: June 22, 2006, 04:58:39 AM »

Also, how do I flash out the codes without a reader? I have the keypad controller with 1-2-3-D and R-N.  Thanks
Logged

1991 Eagle 15
Sammy
Hero Member
*****
Offline Offline

Posts: 523




Ignore
« Reply #7 on: June 22, 2006, 02:46:44 PM »

You should have some type of diagnostic test switch, then code will flash out on the check trans light.
It might be near the trans ECU (computer).
See what you can do. If you can get a code, I'll help diagnose it for you.
I would also check the output speed sensor on the trans and it's connections.
Unplug the 2 pin connector and check the resistance of the sensor.
Let me know what you get.
Sammy  Cool

Logged
homermandy
Jr. Member
**
Offline Offline

Posts: 85




Ignore
« Reply #8 on: June 22, 2006, 06:14:55 PM »

Thanks Sammy. I will check tomorrow. Turns out the Authorized Allison Detroit Dealer never found any software to read my Allison HT746. So it sat ther all week. Anyways, I picked it up(no charge) and started driving home. It stayed in 1st fear for about 5 minutes then all of a sudden the trans operated perfectly all the way home. I'm starting to suspect a connection or electrical problem. I need to get some manuals.

On a side note, I did get my 6V92T in-framed when I purchased the coach. I'm not sure why I get excessive black smoke on acceleration. I can understand on heavy acceleraction, but it seems it smokes a little too much. I get about 16PSI boost on a hill, new air filter, rebuilt blower. Any suggestions on the black smoke would be greatly appreciated. It is a DDEC2. Thanks
Logged

1991 Eagle 15
Sammy
Hero Member
*****
Offline Offline

Posts: 523




Ignore
« Reply #9 on: June 22, 2006, 06:53:11 PM »

I would check the turbo boost sensor. I believe there is a rubber line that connects to the sensor, it collapses or splits sometimes.
This will cause sensor to send wrong info to DDEC  ECM. If you have the "bypass"blower - (has a bypass valve on top, near rear) check the small rubber hose on it  - collapses or splits also.
Make sure all hoses and clamps on air intake and compressor sides of turbo are in good condition and secured properly.
Let us know what you find.
Sammy  Cool
Logged
homermandy
Jr. Member
**
Offline Offline

Posts: 85




Ignore
« Reply #10 on: June 23, 2006, 06:09:03 PM »

Sammy,
 Well, I am pretty happy tonight. I got under the bus to check resistance of 2 wire plug going into trans. Resistance was about 145 ohms. I then proceeded to check the large connector into the trans and it looked good. Didn;t want to unscrew it(wasnt sure if i should). Well I got to looking in the engine bay and looked at the tube from the turbo to thesensor and it looked fine. Then, low and behold, I looked at the turbo connection into the top of the blower I assume, There is a large rubber boot with 2 clamps(I assume to connect turbo to blower). THE ONE CLAMP(TOP ONE CLOSEST TO TURBO) WAS DANGLING. I could put my finger under the hose if I tried. When they did the rebuild, they must have forgot to tighten the clamp because it was actually DANGLING. Anyways, I tightened it down and will test tomorrow. Makes sense though that that massive air leak would cause less air into the blower. I'm keeping my fingers crossed that this is the black smoke issue. I will try tomorrow and let you know. Also, does the resistance sound right for the plug into the trans? Thanks
Logged

1991 Eagle 15
Sammy
Hero Member
*****
Offline Offline

Posts: 523




Ignore
« Reply #11 on: June 23, 2006, 06:54:23 PM »

Resistance value is good - range is from 115 to 165 ohms.
Glad you found a loose hose.Hopefully that's your black smoke problem.
Now about the ATEC codes... did you try to "blink' or "flash" them out?
Your local dealer needs an ATEC cartridge and a Pro-Link.
Try a local transit garage,they might have one. Many transit coaches have ATEC.
If you lived closer I'd come do it myself for you,LOL.
Sammy  Cool
Logged
niles500
Niles500
Hero Member
*****
Offline Offline

Posts: 1188


ROSIE




Ignore
« Reply #12 on: June 23, 2006, 07:37:15 PM »

http://www.tpub.com/content/semis/TM-9-2320-364-20-1/css/TM-9-2320-364-20-1_170.htm

http://www.tpub.com/content/semis/TM-9-2320-364-20-1/css/TM-9-2320-364-20-1_171.htm

http://www.tpub.com/content/semis/TM-9-2320-364-20-1/css/TM-9-2320-364-20-1_172.htm

http://www.tpub.com/content/semis/TM-9-2320-364-20-1/css/TM-9-2320-364-20-1_173.htm

http://www.tpub.com/content/semis/TM-9-2320-364-20-1/css/TM-9-2320-364-20-1_174.htm

http://www.tpub.com/content/semis/TM-9-2320-364-20-1/css/TM-9-2320-364-20-1_175.htm

http://www.tpub.com/content/semis/TM-9-2320-364-20-1/css/TM-9-2320-364-20-1_176.htm

for general info on ATEC's - HTH


Logged

(\__/)
(='.'=)
(")_(")  

- Niles
homermandy
Jr. Member
**
Offline Offline

Posts: 85




Ignore
« Reply #13 on: June 24, 2006, 06:13:21 AM »

Wow, Thanks Niles. I will try that today. I appreciate all the help.
Logged

1991 Eagle 15
homermandy
Jr. Member
**
Offline Offline

Posts: 85




Ignore
« Reply #14 on: June 24, 2006, 06:50:14 PM »

Ok, here is the latest. I took the bus for a test ride after tightening up the clamp on the turbo. OMG. Talk abotu night and day. No black smoke, turbo kicks right in, got up to 80 on highway and had to back down. Boost read as high as 21lbs. Wow, now this is what a newly rebuild motor should do.

Now the bad part. Coming back on the highway, DO NOT SHIFT light goes off. I have to get off at an exit and it stays locked in 4th. I turn off the engine since it is bucking from not unlocking torque converter. Turn back on, switch to drive and get back home with no more light.

Good news is I actually have a diagnostic switch on my dash for engine and trans. I actually got the eninge to flash codes of:
36
43
44
45
58
36
43

Not sure what they mean, Anyone?  Now the trans diagnostic light does light up before I start the engine, but when I hit it's diagnostic button, no codes flashed. I'm assuming there may be no codes?

My other theory is both times the DO NOT SHIFT light beeped was on the highway, hot day, and really getting on it with the motor.  Now I  do have a Trans Temp guage, but it does not work. I have not traced the wire from the guage, etc. Guage may actually be broken, Where does the guage get it's signal? The computer? Also. do you think switching to synthetic will cure the problem if it is overheating?  I currently have Allison approved Coastal brand ATF in it now. 

Odd thing is. when I changed the trans fluid last month to Coastal, I did drive the bus about 400 miles to Kentucky back to Ohio in some super hilly areas and the DO NOT SHIFT LIGHT did NOT come on. Which makes me think my theory of overheating may not be right?

Geesh, at least I'm happy about the motor. Now I need to get this annoying trans thing fixed. Also, any idea on the motor codes?

Thanks for all the help.

Logged

1991 Eagle 15
homermandy
Jr. Member
**
Offline Offline

Posts: 85




Ignore
« Reply #15 on: June 24, 2006, 07:05:57 PM »

Forgot to mention. The Operators manual I downloaded from Allison says when Operatiing conditions are exceeded, EITHER the CHECK TRANS light OR the CHEACK TRANS AND DO NOT SHIFT lights come on. Now my CHEACK TRANS light does NOT come on when the DO NOT SHIFT light goes on. Thanks
Logged

1991 Eagle 15
NJT5047
Hero Member
*****
Offline Offline

Posts: 1942





Ignore
« Reply #16 on: June 24, 2006, 08:30:56 PM »

Clear all the codes and start over.  The code "43" is low coolant.  Low Coolant  is usually  a show stopper.  Code 43 will set both engine CEL and "Do not shift" lite.   If the system's working correctly, the code 43 should shut the engine down.
After the DDEC ECM is cleared, operate the coach and see what codes are reset. 
Check your coolant level.   I'm unaware that this would cause the trans to not unlock the converter...? 
Sounds like you have some loose wiring with all those codes...not at all llikely that each code indicates an actual malfunction.   Could be a plug, or harness damaged or broken. 
Code 44 is high oil temp (engine) and code 45 is low oil pressure.  Is it possible that your rebuild is heating up the trans?
JR
« Last Edit: June 24, 2006, 08:40:03 PM by NJT5047 » Logged

JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.”

Ayn Rand
homermandy
Jr. Member
**
Offline Offline

Posts: 85




Ignore
« Reply #17 on: June 25, 2006, 06:43:17 AM »

Thanks for the reply. I'll check coolant level. These codes may also have been there after they finished the rebuild and were testing it. They may not have cleared codes. Is it possible to reset the DDEC without a reader? Like disconnecting the batteries for a while?  Also, how do I properly take off the ATEC plug at the trans? Does it just unscrew? Thanks
Logged

1991 Eagle 15
Sammy
Hero Member
*****
Offline Offline

Posts: 523




Ignore
« Reply #18 on: June 25, 2006, 08:54:10 AM »

DDEC codes can only be cleared with A Pro Link or DDDL software.
Code 58 is a cruise control code.
I'd check the two 30 pin connectors at the DDEC  ECM (computer) also.
Shut off the batterys, disconnect the two 30 pin connectors, make sure connectors are clean. look at ECM - make sure none of the pins are bent also. Reconnect and secure the two 30 pin connectors.
You should be able to unscrew the ring on the ATEC connector at the trans.
Make sure all is clean, no bent pins.
I agree with JR, codes are most likely old - historic, (inactive).
You need to have them cleared to know what's going on now.
Good luck with your repairs.
Sammy  Cool
« Last Edit: June 25, 2006, 08:58:00 AM by Sammy » Logged
Pages: 1 2 [All]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines Valid XHTML 1.0! Valid CSS!