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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: bigred on September 23, 2014, 12:19:24 PM

Title: HT755CR Allison
Post by: bigred on September 23, 2014, 12:19:24 PM
Recently,I took the old Prevost and had the oil changed.After that ,we took it to a local camp ground to check out the other systems.bus was running fine when we pulled into the campground .We left it there for two days .Went to pick it up,started it ,built up air pressure released the parking brake ,put it in drive ,nothing happens.Put it in reverse ,nothing happens .It is almost like someone stole the tranny while it was parked there .I did the usual things like starting and stopping the engine and disconnecting the batteries.All to no avail. I called my road service and reached the conclusion that I would need to be towed to a repair facility.They had checked and there was two Allison repair shops near Asheville ,WNC Freightliner and Ken Wilson Heavy Truck repair.I chose Freightliner because it was closer.Had to leave it there for a week because their transmission man was away for Allison training.He got back and called me to come out to the bus and talk with him.Met him ,showed him the controls ,tried to get the bus to move,and it would not .Just from talking to the guy,I could tell he either couldn't or wouldn't fix that transmission.Sure enough ,he called me that afternoon and told me he wouldn't be able to "help" me (They charged me 168.00 for that tidbit).I called my road service and they graciously agreed to tow the bus on to Ken Wilson(I can't say enough good things about G S road service).I called Ken Wilson and told them that the tranny was an HT755CR and asked could they work on it.I was informed that altho this was something of an odd ball tranny but they could work on it, but they were running about two weeks behind.After two tows and three weeks.The batteries were down .They used a jump box to start it and the sob went into gear and ran like nothing had been wrong with it to start with.Has anyone ever had this or a similar experience?
Title: Re: HT755CR Allison
Post by: tomhamrick on September 24, 2014, 07:13:51 AM
I have had this happen a few times with my 755CR and it is normally when my auxiliary air is low. I am not sure what it does but there is a small air line running from an auxiliary block in the engine compartment of my Prevost to the 755CR. I have installed a gauge for my auxiliary air and it does not air up until after the brakes air up. Make sure you have good auxiliary air pressure.
Title: Re: HT755CR Allison
Post by: luvrbus on September 24, 2014, 07:24:06 AM
Most of those are interlocked into the high and low leveling also, the 700 series ATEC live in their own private little world  ;D
Title: Re: HT755CR Allison
Post by: TomC on September 24, 2014, 08:15:31 AM
Love my mechanical HT740.
Title: Re: HT755CR Allison
Post by: muldoonman on September 24, 2014, 05:22:04 PM
Have had mine refuse a couple times to go into gear after running a couple hundred miles and stopping. Had to go from neutral to drive a couple times and it would hit drive. Has 72,300 miles on it and 8V92TA.
Title: Re: HT755CR Allison
Post by: bigred on September 25, 2014, 12:13:42 PM
Yep !! Had that happen to me on my previous motor home and I can tell you there is nothing like that sinking feeling you get when you are in Rodanthe on the N C OBX and you put it in gear and nothing happens.
Title: Re: HT755CR Allison
Post by: Oonrahnjay on September 25, 2014, 03:37:06 PM
Quote from: bigred on September 25, 2014, 12:13:42 PM
Yep !! Had that happen to me on my previous motor home and I can tell you there is nothing like that sinking feeling you get when you are in Rodanthe on the N C OBX and you put it in gear and nothing happens.

    Howjoo deal with that, Red?
Title: Re: HT755CR Allison
Post by: bigred on September 26, 2014, 03:00:57 PM
Kept starting and stopping the engine.After about three times it went in gear.Had a scan ran on when we got back home .They think that a heat sensor wire was the culprit.
Title: Re: HT755CR Allison
Post by: eagle19952 on September 26, 2014, 04:08:29 PM
Quote from: bigred on September 26, 2014, 03:00:57 PM
Kept starting and stopping the engine.After about three times it went in gear.Had a scan ran on when we got back home .They think that a heat sensor wire was the culprit.

seems like they never know....just empty your wallet... :(
Title: Re: HT755CR Allison
Post by: Oonrahnjay on September 29, 2014, 08:35:14 PM
Quote from: bigred on September 26, 2014, 03:00:57 PM
Kept starting and stopping the engine.After about three times it went in gear. ...

      Yeah, nice when it will happen but I worry that if it has a problem, maybe there's a time when it will happen but not "fix itself".
Title: Re: HT755CR Allison
Post by: luvrbus on September 29, 2014, 08:44:57 PM
Bob Ware the guru of all guru on Allison transmission says the 700 ATEC is the hookers best friend talking about tow truck drivers
Title: Re: HT755CR Allison
Post by: bigred on October 01, 2014, 10:31:48 AM
I can believe it ! Road service has already paid the "hookers" twice.Is this not a common transmission on the early to mid 90's Prevosts and MCI'S??
Title: Re: HT755CR Allison
Post by: luvrbus on October 01, 2014, 10:48:23 AM
Eagles didn't get left out either Red, Allison had to start somewhere just be happy you not are dealing with Allison 741 ???
Title: Re: HT755CR Allison
Post by: bigred on October 02, 2014, 03:50:09 PM
Just goes to prove ,no matter how bad things are ,somewhere sometime someone is worse off! Mine has the tech scratching his head. Has no codes stored and has went in gear every time he has tried it.As a matter of fact ,he say's he can't make it not go in gear!!
Title: Re: HT755CR Allison
Post by: luvrbus on October 02, 2014, 04:13:17 PM
I feel for him those frustrate me so much with a transmission TCM and a manufactures TCM I gave Don Fairchlid all the manuals and trouble shooting guides I had to let him worry with those  ::)