Bus Conversion Magazine Bulletin Board
December 12, 2017, 12:34:40 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
News: If your computer is lost, damaged, or stolen, your Online mags will be safe.
   Home   Help Forum Rules Search Calendar Login Register BCM Home Page Contact BCM  
Pages: 1 2 [All]   Go Down
  Print  
Author Topic: Allison trans is jumping around  (Read 1125 times)
Scott & Heather
Scott & Heather's buses: MCI-9 & MCI-102
Hero Member
*****
Offline Offline

Posts: 4036


MCI-9 & MCI-102


WWW

Ignore
« on: September 24, 2017, 06:03:04 PM »

So my Allison 748 has been starting to jump in and out of gearish for the past month. Actually it feels and sounds like the torque converter is losing lockup and slipping in and out of it. It's not constant and not often but it's definitely happening. Of course I had a trans fluid and filter change this past spring. (April). But it hasn't done it until just about a month ago. Fluid level is good, already checked that. Anything else easy I should check?


Sent from my iPhone using Tapatalk Pro
Logged

Scott & Heather
1984 MCI 9 6V92-turbo with 9 inch roof raise (SOLD)
1992 MCI 102C3 8v92-turbo with 8 inch roof raise CURRENT HOME
Click link for 900 photos of our 1st bus conversion:
https://goo.gl/photos/GVtNRniG2RBXPuXW9
Bill Gerrie
Full Member
***
Offline Offline

Posts: 102




Ignore
« Reply #1 on: September 24, 2017, 06:18:08 PM »

If you have an ATEC transmission computer it is possible that wire 201 (K2) which goes to chassis ground is a bad connection. If it is corroded or lose it will cause the symptoms you describe.
Logged
Scott & Heather
Scott & Heather's buses: MCI-9 & MCI-102
Hero Member
*****
Offline Offline

Posts: 4036


MCI-9 & MCI-102


WWW

Ignore
« Reply #2 on: September 25, 2017, 06:29:22 AM »

I do indeed have an ATEC trans. I'll see if I can chase down wire 201 and be sure I have a good ground. Thanks Bill.


Sent from my iPhone using Tapatalk Pro
Logged

Scott & Heather
1984 MCI 9 6V92-turbo with 9 inch roof raise (SOLD)
1992 MCI 102C3 8v92-turbo with 8 inch roof raise CURRENT HOME
Click link for 900 photos of our 1st bus conversion:
https://goo.gl/photos/GVtNRniG2RBXPuXW9
luvrbus
Hero Member
*****
Offline Offline

Posts: 18568




Ignore
« Reply #3 on: September 25, 2017, 06:33:16 AM »

Could be a solenoid getting weak also 
Logged

Life is short drink the good wine first
thomasinnv
Derrick Thomas
Hero Member
*****
Offline Offline

Posts: 1183


I may be nuts, but only for buses




Ignore
Re:
« Reply #4 on: September 25, 2017, 08:41:05 AM »

No stored codes? You can pull codes through the shifter pad.

Sent from my SM-G920T using Tapatalk
Logged

Some are called, some are sent, some just got up and went.

1998 MCI 102-DL3
Series 60 11.1/Alison B500
95% converted (they're never really done, are they?)
Scott & Heather
Scott & Heather's buses: MCI-9 & MCI-102
Hero Member
*****
Offline Offline

Posts: 4036


MCI-9 & MCI-102


WWW

Ignore
« Reply #5 on: November 08, 2017, 11:26:40 AM »

Guys, my jumping in and out of lockup is getting worse. Driving past mount Shasta on the way to Portland it just kept popping out of lockup and then when I would stop at a truck stop right after exiting the HWy, bus would be sluggish to move and then trans would seem to "catch" and then go. The next day, drove fine for hours and then started acting up. Drives fine mostly on the flats but get in the hills and she starts getting jumpy. Fluid level is good, fluid color and smell are good. No shift malfunction lights or anything. No engine codes being thrown. I'm at a loss here.


Sent from my iPhone using Tapatalk Pro
Logged

Scott & Heather
1984 MCI 9 6V92-turbo with 9 inch roof raise (SOLD)
1992 MCI 102C3 8v92-turbo with 8 inch roof raise CURRENT HOME
Click link for 900 photos of our 1st bus conversion:
https://goo.gl/photos/GVtNRniG2RBXPuXW9
luvrbus
Hero Member
*****
Offline Offline

Posts: 18568




Ignore
« Reply #6 on: November 08, 2017, 11:47:42 AM »

Basically you have a 740 with 5 or 6 solenoids on the valve body you are losing lockup pressure could be the solenoid,springs,governor,the lockup valve going bad or the torque converter have a transmission shop check your pressures it not that expensive and time consuming and stop looking for a code   
Logged

Life is short drink the good wine first
Scott & Heather
Scott & Heather's buses: MCI-9 & MCI-102
Hero Member
*****
Offline Offline

Posts: 4036


MCI-9 & MCI-102


WWW

Ignore
« Reply #7 on: November 08, 2017, 12:55:54 PM »

Lol. Ok cliff. I'll see if I can sneak the coach into a shop somewhere near Indianapolis.


Sent from my iPhone using Tapatalk Pro
Logged

Scott & Heather
1984 MCI 9 6V92-turbo with 9 inch roof raise (SOLD)
1992 MCI 102C3 8v92-turbo with 8 inch roof raise CURRENT HOME
Click link for 900 photos of our 1st bus conversion:
https://goo.gl/photos/GVtNRniG2RBXPuXW9
sledhead
Hero Member
*****
Offline Offline

Posts: 822





Ignore
« Reply #8 on: November 08, 2017, 05:15:10 PM »

mine did somewhat the same thing and it ended up being a broken wire from the ecm to the transmission ( ht740 ) I had to leave the coach at leids diesel when the turbo went bad and when I returned to pick it up they had a new wire run along side the wiring harness and a rebuilt turbo to boot at no charge . great guys

dave   
Logged

dave , karen
1990 mci 102c  6v92 ta ht740  kit,living room slide .... sold
2000 featherlite vogue vantare 550 hp cat
 home base huntsville ontario canada
Scott & Heather
Scott & Heather's buses: MCI-9 & MCI-102
Hero Member
*****
Offline Offline

Posts: 4036


MCI-9 & MCI-102


WWW

Ignore
« Reply #9 on: November 08, 2017, 05:45:55 PM »

Dave you can't remember which wire right?


Sent from my iPhone using Tapatalk Pro
Logged

Scott & Heather
1984 MCI 9 6V92-turbo with 9 inch roof raise (SOLD)
1992 MCI 102C3 8v92-turbo with 8 inch roof raise CURRENT HOME
Click link for 900 photos of our 1st bus conversion:
https://goo.gl/photos/GVtNRniG2RBXPuXW9
sledhead
Hero Member
*****
Offline Offline

Posts: 822





Ignore
« Reply #10 on: November 08, 2017, 06:00:09 PM »

to be honest it started on the trip to lieds diesel 11 hour drive and they didn't even tell me that they had fixed it until I asked about the added wire

so no I do not know what it fixed but never had a problem shifting  in the 6 years after that

dave
Logged

dave , karen
1990 mci 102c  6v92 ta ht740  kit,living room slide .... sold
2000 featherlite vogue vantare 550 hp cat
 home base huntsville ontario canada
Scott & Heather
Scott & Heather's buses: MCI-9 & MCI-102
Hero Member
*****
Offline Offline

Posts: 4036


MCI-9 & MCI-102


WWW

Ignore
« Reply #11 on: November 08, 2017, 09:48:27 PM »

Ok thanks. To the shop she goes.... again sigh


Sent from my iPhone using Tapatalk Pro
Logged

Scott & Heather
1984 MCI 9 6V92-turbo with 9 inch roof raise (SOLD)
1992 MCI 102C3 8v92-turbo with 8 inch roof raise CURRENT HOME
Click link for 900 photos of our 1st bus conversion:
https://goo.gl/photos/GVtNRniG2RBXPuXW9
bigred
Hero Member
*****
Offline Offline

Posts: 626




Ignore
« Reply #12 on: November 09, 2017, 07:43:34 AM »

Scott:My American Coach has the six speed Allison tranny .Three years ago after having the fluid and filters changed it started acting squirrely coming out of lock up slamming from one gear to the other and all sorts of crazy things .After spending almost 4500 dollars with Clark Power starting with 2800 dollars for a TCU .Took the unit back to them four times and they charged me every time .I finally took it to their shop in Greensboro and the guy's down there got it fixed .According to what the tech told me,there is a gasket that people who are not familiar with Allison sometimes mess up during fluid and filter changes creating a low pressure condition on "port 5 " .Before you get into a big drawn out affair with yours have them check the pressure on ports .This cost me 800 dollars (which I also had to pay) .If I had known about this ,I would be 3500 dollars better off.I am trying to find the invoice where they did this work .Had it just a while back but danged if I know what I did with it!!! 
Logged

Rhet Raby           137 Elk Mtn Rd       Asheville N c 28804             1993 Prevost XL
luvrbus
Hero Member
*****
Offline Offline

Posts: 18568




Ignore
« Reply #13 on: November 09, 2017, 07:54:08 AM »

Pressure is the key to a Allison for sure
Logged

Life is short drink the good wine first
Scott & Heather
Scott & Heather's buses: MCI-9 & MCI-102
Hero Member
*****
Offline Offline

Posts: 4036


MCI-9 & MCI-102


WWW

Ignore
« Reply #14 on: November 09, 2017, 11:48:08 AM »

Thanks a bunch bigred. I'll check into this. And if that turns out to be the case, I'll be in contact with Stewart and Stevenson in Texas to rectify this.


Sent from my iPhone using Tapatalk Pro
Logged

Scott & Heather
1984 MCI 9 6V92-turbo with 9 inch roof raise (SOLD)
1992 MCI 102C3 8v92-turbo with 8 inch roof raise CURRENT HOME
Click link for 900 photos of our 1st bus conversion:
https://goo.gl/photos/GVtNRniG2RBXPuXW9
luvrbus
Hero Member
*****
Offline Offline

Posts: 18568




Ignore
« Reply #15 on: November 09, 2017, 12:58:57 PM »

A 6 speed Red is speaking of is a World Transmission with the internal filters yours is not even close,the 700 series use a latching relay to keep it in lockup  
« Last Edit: November 09, 2017, 01:42:54 PM by luvrbus » Logged

Life is short drink the good wine first
Scott & Heather
Scott & Heather's buses: MCI-9 & MCI-102
Hero Member
*****
Offline Offline

Posts: 4036


MCI-9 & MCI-102


WWW

Ignore
« Reply #16 on: November 09, 2017, 02:00:55 PM »

Ok thanks cliff. I won't strangle Stewart and Stevenson now. Lol


Sent from my iPhone using Tapatalk Pro
Logged

Scott & Heather
1984 MCI 9 6V92-turbo with 9 inch roof raise (SOLD)
1992 MCI 102C3 8v92-turbo with 8 inch roof raise CURRENT HOME
Click link for 900 photos of our 1st bus conversion:
https://goo.gl/photos/GVtNRniG2RBXPuXW9
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!