| Search | Statistics | User Listing | Member Roster | Coach DB | Forums | Albums |
| Home -> FMC Owner's Forum -> General Discussion -> Mechanic's Corner -> View Thread |
| ||
| ||
|
| You are logged in as a guest. ( logon | register ) |
 A transmission discussionJump to page : 1 Now viewing page 1 [25 messages per page] | View previous thread :: View next thread |
| General Discussion -> Mechanic's Corner | Message format |
BigRabbitMan |
| ||
Expert   Location: Cottage Grove, OR | The following is a copy of a posting i made on the Yahoo group site. Bruce, all FMC's originally had the Chrysler Corp 727 transmission exceptthe approximately 100 coaches that were originally configured as transit coaches and not as motor homes. Those units were originally outfitted with an Allison AT 545 transmission due to the stop and go nature of the application. The 727 is a 3 speed transmission and the 545 is a four speed transmission with both being 1:1 in high gear. All FMC's were also originally gas using the Chrysler 440-I or industrial version of the 440. The Allison 545 is a heavy duty transmission rated up to 30,000 lbs (twice the weight of an FMC) and was used from the '60s to the '90s for medium duty trucks, school busses, etc. They were very popular in stop and go situations like transit buses, garbage trucks, fire trucks, delivery trucks, etc. Allison had many other models for heavier duty applications like over the road trucks, large busses, etc. A few owners of gas powered FMC's, such as myself, have switched to the 545 for better gear selection at slower speeds and in the mountains. Some of the units that were originally transits have been converted to being motor homes as well and those would have the 545. Most use the standard 727 as it is a tough transmission and works well. For normal use, there is no reason to change. A number of FMC's have been converted to a diesel engine. Many to 8.2LT Detroit Diesel's and some to Cummins or other brands. All of these need to have a transmission change as a diesel engine puts out much higher torque at slower engine rpm. To my knowledge, until recently virtually all of these used the Allison 545 along with rear end ratio and wheel size changes to achieve the desired engine to ground gearing needed to properly operate a diesel. Around 2000 Allison stopped making the 545 and replaced it with the 1000-2000 series transmissions. These are 5 and 6 speed electronically controlled transmissions that are used with modern electronically controlled gas or diesel engines. Since about that time, some coaches have been converted to either the GM Duramax and matching transmission or the Ford Powerstroke and matching transmission. The only difference between a 545 used for a gas application and a diesel application is the torque converter. The one on a gas engine needs a torque converter that allows more slippage at low engine speeds so the engine rpm can get up to the operating area whereas the diesel requires much less low speed slippage as that is where a diesel engine does it's work. A number of the members of this group have diesels in their coaches. To actually do the conversion is a major, major project and not for the light hearted and costs significant dollars due to all of the systems that need to be changed, but those that drive them really like them. In the files section of the Yahoo Group FMCMotorCoach2 there are spec sheets for the Allison transmissions and a couple of Diesel engines. That group was created to get the additional file and photo space and is not a discussion group. If you have an interest in this area, you need to review those files in addition to the ones for this group. Hopefully I have helped clarify what is experienced in FMC land! Do you have an FMC or are you considering purchasing one? Stephen Heinrichs, 1046 -----Original Message----- From: FMCMotorCoach@yahoogroups.com [mailto:FMCMotorCoach@yahoogroups.com] On Behalf Of xxxxxxxxxx Sent: Sunday, March 01, 2009 2:44 PM To: FMCMotorCoach@yahoogroups.com Subject: [FMCMotorCoach] FMC transmissions I've seen where some FMC's have an Allison transmission. ....is that how they were equipped or does allison just have one for them?If they | ||
| |||
| Jump to page : 1 Now viewing page 1 [25 messages per page] |
| Search this forum Printer friendly version E-mail a link to this thread |
 | Running MegaBBS ASP Forum Software © 2002-2026 PD9 Software | (Delete all cookies set by this site) |
