Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Display Modes
 
Old 11-06-2018, 09:08 PM   #1
Mini-Skoolie
 
Join Date: Nov 2018
Location: frederick md
Posts: 35
Year: 1995
Coachwork: Thomas
Engine: 8.3 Cummins mechanical injection
Rear engine manual Thomas?

I have been doing lots of research on what the ideal bus for me to buy would be, and I'm pretty sure a rear engine Thomas with a mechanical Cummins 8.3 and mt643 transmission or larger (so not the 545) is best. However, I would prefer a manual transmission if I can get one. My question is, were Thomas rear engine busses ever made with manual transmissions? If so, what is the shift linkage like? How hard are they to find? Were [I]any[I] rear engine busses ever manual? I haven't been able to find any definitive answers here or elsewhere, only that manuals in general are hard to find. Any help would be appreciated

Jackula is offline   Reply With Quote
Old 11-06-2018, 10:05 PM   #2
Bus Crazy
 
Join Date: Jun 2016
Location: Orange County, CA
Posts: 1,363
Year: 1990
Coachwork: Crown, integral. (With 2kW of tiltable solar)
Chassis: Crown Supercoach II (rear engine)
Engine: Detroit 6V92TAC, DDEC 2, Jake brake, Allison HT740
Rated Cap: 37,400 lbs GVWR
Very few manual pushers at best. I've been in an old Gillig like that, I know of a White pusher with a manual, Crown's high-level tour buses such as the Atomics had 8V71s with 5-speeds, and there may have been an odd Crown Super II with a Cummins CTA and manual, but otherwise I can't think of any others. Good luck in your quixotic search!

John
Iceni John is offline   Reply With Quote
Old 11-07-2018, 12:50 AM   #3
Bus Crazy
 
Join Date: Jul 2011
Location: Winlcok, WA
Posts: 2,233
In WA state the automatic transmission has been in the basic spe'c for more than 20-years. If you wanted a manual transmission you had to pay extra to get one.

To be honest I haven't seen a new bus with a manual transmission for a very LOOOOOOOOOONG time. But occasionally I hear about one that was spe'c'ed with a manual.

The last Thomas Saf-T-Liner ER that I have seen with a manual transmission was made in the '70's. Trust me when I say you would not want that bus even if you got it for free.

Could you install a manual transmission in a Thomas Saf-T-Liner ER? Probably. But it will cost you more than what you would pay for the bus. You would need to find a donor transmission that will mate to your transmission. You would need to swap the flex plate for a flywheel. You would have to design and build proper transmission mounts. You would have to have a new driveshaft made that would mate up to both the transmission and rear end. And then the fun part would begin as you would then have to design and build a clutch and shift linkage in excess of 35'.

You are more likely to find a Crown or a Gillig with a manual transmission. The only caveat to that is the newest Gillig Schoolcoach is a 1982, the newest Crown is a 1991, and the newest Gillig Phantom Schoolcoach is about 1992.
cowlitzcoach is offline   Reply With Quote
Old 11-07-2018, 10:22 AM   #4
Bus Geek
 
Join Date: May 2009
Location: Columbus Ohio
Posts: 18,848
Year: 1991
Coachwork: Carpenter
Chassis: International 3800
Engine: DTA360 / MT643
Rated Cap: 7 Row Handicap
what did they use for shifting? was it just sloppy as heck or was it an air shifter?
cadillackid is offline   Reply With Quote
Old 11-07-2018, 11:09 AM   #5
Bus Geek
 
Join Date: May 2016
Location: Eastern WA
Posts: 6,401
Year: 2002
Coachwork: Bluebird
Chassis: All American RE (A3RE)
Engine: Cummins ISC (8.3)
Rated Cap: 72
My Eagle RE came from the factory with a manual transmission.

It had a 34' long mechanical rod linkage.

The throttle was similar.

Ultimately I wound up with an Allison and an air throttle. Too many problems with the long mechanical linkage.
PNW_Steve is offline   Reply With Quote
Old 11-08-2018, 01:56 AM   #6
Bus Crazy
 
Join Date: Jul 2011
Location: Winlcok, WA
Posts: 2,233
Quote:
Originally Posted by cadillackid View Post
what did they use for shifting? was it just sloppy as heck or was it an air shifter?
Most of the eastern built Type 'D' buses that were sold in WA state before about 1985 were on OEM vendor supplied chassis. The most common one in WA state was on the GMC RE bus chassis. The shift linkage consisted of two bell cranks that went through a pin and clevis every 5' to 10'. By the time the bus had 100K miles on the bus that each hole a pin went through was wollered out a little. Multiply that slop over the multiple number of pins and you ended up with a LOT of slop. The gear shift lever could move more than 12" before anything in the transmission started to move.

We had one Carpenter Corsair RE that when the driver, who was about 5' tall, would reach to grab 4th gear her head would go down below the dashboard. The bus garage got many calls about the driver driving down the road with her head not visible to other drivers. On that bus reverse was up and to the right. When she had to go into reverse she sort of threw the gear shift in the general direction of reverse and then kicked it with her foot the rest of the way. She would hook her foot on the gear shift to pull it back out of reverse. Her arm was just too short to reach that far while keeping her seat belt fastened. We looked at adding an extension on the end with a bend to come back towards the driver's position. But it was just as sloppy on the near side. You never used deep low which was up and to the left. When you shifted from 2nd into 3rd which was down and to the left you would have to lift your hip a little to get the gear shift over and down far enough to go into gear.

The IHC OEM vendor supplied RE bus chassis used a single shaft to shift the Fuller transmission. The IHC chassis was heavier duty than the GMC so everything about it felt more solid.
cowlitzcoach is offline   Reply With Quote
Old 11-08-2018, 04:32 AM   #7
Bus Geek
 
Join Date: May 2009
Location: Columbus Ohio
Posts: 18,848
Year: 1991
Coachwork: Carpenter
Chassis: International 3800
Engine: DTA360 / MT643
Rated Cap: 7 Row Handicap
Fun stuff!!
While I dig old busses and admittedly I like my busses to stay busses, I surely am glad they are all automatics .. even if I am hard on At545s( I seem to ruin them ).

It seems like even the CE style busses with stick are spicers and sloppy. Eaton fuller like in trucks seem tighter.
cadillackid is offline   Reply With Quote
Old 02-19-2024, 10:22 PM   #8
New Member
 
Join Date: Feb 2024
Posts: 1
Quote:
Originally Posted by Jackula View Post
I have been doing lots of research on what the ideal bus for me to buy would be, and I'm pretty sure a rear engine Thomas with a mechanical Cummins 8.3 and mt643 transmission or larger (so not the 545) is best. However, I would prefer a manual transmission if I can get one. My question is, were Thomas rear engine busses ever made with manual transmissions? If so, what is the shift linkage like? How hard are they to find? Were [I]any[I] rear engine busses ever manual? I haven't been able to find any definitive answers here or elsewhere, only that manuals in general are hard to find. Any help would be appreciated
Doe's Cummings have a rear mount
Bell housing, for a NV 4500.
Trying to replace rear mount 545 Alison with manual.
Edward Curry is offline   Reply With Quote
Old 02-20-2024, 06:53 AM   #9
Bus Geek
 
Join Date: May 2009
Location: Columbus Ohio
Posts: 18,848
Year: 1991
Coachwork: Carpenter
Chassis: International 3800
Engine: DTA360 / MT643
Rated Cap: 7 Row Handicap
Quote:
Originally Posted by Edward Curry View Post
Doe's Cummings have a rear mount
Bell housing, for a NV 4500.
Trying to replace rear mount 545 Alison with manual.



I havent seen a rear engine manual bus since the old GMC fishbowls and the crowns... (manuals were offered in both rear and mid engine crowns) I would think the flywheel housing would be the same for manual or auto.. the flywheel would be different..


the crowns were fitted to big cummins or detroits but used SAE2 bell housings to mate to eaton fuller transmissions.. since the cummins 5.9s were offered in manual transmission front engine busses you should be able to find a suitable flywheel and clutch.
cadillackid is offline   Reply With Quote
Old 02-20-2024, 07:42 PM   #10
Bus Nut
 
Crown_Guy's Avatar
 
Join Date: Dec 2013
Location: SoCal
Posts: 389
Year: 1989
Coachwork: Crown Coach
Chassis: 40ft 3-axle 10spd O/D, Factory A/C
Engine: 300hp Cummins 855
Rated Cap: 91
One really good solution for the long distances to a rear mounted engine/transmission is to simply use a pair of TeleFlex or CableCraft push-pull cables. These are a very good, quick, and dirty solution that are fairly easy to engineer and install. I replaced the entirety of both shift linkages rods and bell-cranks in my Scenicruiser when the existing stuff became just too hard to keep maintained. They were installed from the shift tower under the floor by the driver all the way to the transmission shift tower. The two cables were only pushing and pulling one of the two levers on the top of the transmission. Easy-Peasy really. The super high quality of the Cable-Craft cables I bought had a Teflon interior coating that reduced friction to the point that I could literally shift the thing with two fingers and very gently feel my way into each gear. It was so good, with extremely precise feel through the cables, I was able to shift the bus without the clutch from then on. It was such a solid feel with zero lost motion either pushing or pulling that it felt like a solid rod connecting to the transmission. It definitely made a believer out of me and I've always said if I ever needed to do some seriously drastic repair, upgrade, or modification of any kind of shift linkage nightmare, and that includes throttle cables too, I could rest easy knowing that the high quality push-pull cables available are a perfect solution. You should look into this yourself and I'm sure you'll be pleasantly surprised at the easy solutions they provide. Most all distributors of each of these Brands have the parts and tooling on hand to custom fabricate whatever you need for end terminations as well as needed lengths.

It's maybe not well known but when you do the research you'll be surprised at how good the cable solutions can really be. Very reasonable in costs, and installation hassles are greatly reduced even in those tight quarters and weird routing situations of which buses tend to have so many of. Good hunting.
Crown_Guy is offline   Reply With Quote
Old 02-21-2024, 10:52 AM   #11
Bus Geek
 
Join Date: May 2009
Location: Columbus Ohio
Posts: 18,848
Year: 1991
Coachwork: Carpenter
Chassis: International 3800
Engine: DTA360 / MT643
Rated Cap: 7 Row Handicap
Quote:
Originally Posted by Crown_Guy View Post
One really good solution for the long distances to a rear mounted engine/transmission is to simply use a pair of TeleFlex or CableCraft push-pull cables. These are a very good, quick, and dirty solution that are fairly easy to engineer and install. I replaced the entirety of both shift linkages rods and bell-cranks in my Scenicruiser when the existing stuff became just too hard to keep maintained. They were installed from the shift tower under the floor by the driver all the way to the transmission shift tower. The two cables were only pushing and pulling one of the two levers on the top of the transmission. Easy-Peasy really. The super high quality of the Cable-Craft cables I bought had a Teflon interior coating that reduced friction to the point that I could literally shift the thing with two fingers and very gently feel my way into each gear. It was so good, with extremely precise feel through the cables, I was able to shift the bus without the clutch from then on. It was such a solid feel with zero lost motion either pushing or pulling that it felt like a solid rod connecting to the transmission. It definitely made a believer out of me and I've always said if I ever needed to do some seriously drastic repair, upgrade, or modification of any kind of shift linkage nightmare, and that includes throttle cables too, I could rest easy knowing that the high quality push-pull cables available are a perfect solution. You should look into this yourself and I'm sure you'll be pleasantly surprised at the easy solutions they provide. Most all distributors of each of these Brands have the parts and tooling on hand to custom fabricate whatever you need for end terminations as well as needed lengths.

It's maybe not well known but when you do the research you'll be surprised at how good the cable solutions can really be. Very reasonable in costs, and installation hassles are greatly reduced even in those tight quarters and weird routing situations of which buses tend to have so many of. Good hunting.

cool stuff on the cables!! something for me to think about when I finally get into restoring my fishbowl.. the shifter isnt horrible but definitely has slop in it for sure..
cadillackid is offline   Reply With Quote
Old 02-21-2024, 04:56 PM   #12
Bus Nut
 
Crown_Guy's Avatar
 
Join Date: Dec 2013
Location: SoCal
Posts: 389
Year: 1989
Coachwork: Crown Coach
Chassis: 40ft 3-axle 10spd O/D, Factory A/C
Engine: 300hp Cummins 855
Rated Cap: 91
Quote:
Originally Posted by cadillackid View Post
cool stuff on the cables!! something for me to think about when I finally get into restoring my fishbowl.. the shifter isnt horrible but definitely has slop in it for sure..

GMC products ALL used the same rods and bell-cranks to transmit motion from the front to the transmissions. They varied in the actual number and routing of the rods and locations of bell-cranks due to the actual vehicle in question and body style and underfloor layout.

For instance the single level 4104, 4106 were fairly simple with a minimum of bell-cranks needed to change direction of the motion, and those are at the rear mounted to the firewall and take the motion from the centrally running rods and sending it to the two transmission shift levers. The two shift levers on the transmission each only control one of the internal shift rails. One is 1st-2nd gear and the other is 3rd-4th gear. The rods are connected to their respective shift lever and the motion is carried to the front.

Under the front shift tower below the floor is the mechanism for moving the two shift rods fore and aft. It's internal design is of two square blocks that move independently and attached to their respective rear headed shift rods. These blocks each have a square notch facing each other where the bottom of the shift lever has a heavy duty lug that moves from one to the other in neutral and once engaged in a block can move it either fore or aft. This is why the shift lever will feel very easy and tight to move in neutral yet can be very sloppy with lots of lost motion obvious when actually shifting into or out of a gear.

One area that can really cause a lot of lost motion is the shift tower itself and where it is bolted into the floor. If the bolts loosen up or the floor is rotted the tower will move and the critical pivot fulcrum point at the top will be moving around and not transferring the motion into the rods below the floor. I've experienced this first hand through the years with horribly maintained GMCs and the result can be to make shifting almost impossible. The trick is to flick the wrist when shifting and impart a large amount of initial high speed motion and let inertia take over to move the motion of the rods all the way to the rear.

Reverse is internally controlled by a third shift rail and inaccessible from the normal 1/2, 3/4 shift levers. So GMC devised the electric solenoid to pull the internal lug over into the 3rd reverse rail. This is accomplished with the driver putting it in 1st gear and then hitting the reverse switch/button and pulling it back into 2nd gear. This is the typical GMC manual transmission operation from the very earliest days.

You will be interested to know that to the maximum extent possible GMC designed their buses to use as many as possible common parts and similar overall engineering designs to keep manufacturing costs and bloated parts inventories down. From roughly the 4104/4106 designs they created the city transit models which were almost exactly the same below the floors as the highway buses. You'll find many interchangeable parts for your Fishbowl used in the 4104/4106 models. Main differences are the inline 6 vs the two V-6/8 engines and the design differences needed to operate them. This commonality of design philosophy was one of the many genius innovations GMC did. Many operators liked the overall designs and ease of maintaining the buses to keep them on the road and making money. Simple, easy to repair, and very reliable are all important to a for-profit operator.

You could replace the rods with cables for sure, but it won't be easy since you'll need to gain access to the underfloor tunnel the rods and other lines run through. That's not a normally accessible area and may promote some creative new expletives... Try to secure the front shift tower assembly if possible to the floor and continue to use the below floor shift block system. It's better to use this since it's real easy to attach any new cables to the blocks themselves in place of the current rods' clevis's. That's what I did on the Scenicruiser and it was an extremely simple process since the blocks already have mounting holes to accept the clevis pins.

Instead of going to all the trouble of installing cables you may find it fairly easy to locate the needed parts, bell-cranks, clevises, pins, possibly new or from another donor bus where they aren't so worn. Remember to look at highway buses since they will be very similar if not identical parts. Then make the effort to repair and tighten the front shift tower to the floor so it doesn't move at all. This will make a huge difference in the whole system response. It's an easily overlooked problem area.

Sorry for the length but I do get carried away sometimes trying to make myself clear on what I'm describing. Good luck and happy hunting.
Crown_Guy is offline   Reply With Quote
Old 02-21-2024, 05:17 PM   #13
Bus Geek
 
Join Date: May 2009
Location: Columbus Ohio
Posts: 18,848
Year: 1991
Coachwork: Carpenter
Chassis: International 3800
Engine: DTA360 / MT643
Rated Cap: 7 Row Handicap
Quote:
Originally Posted by Crown_Guy View Post
GMC products ALL used the same rods and bell-cranks to transmit motion from the front to the transmissions. They varied in the actual number and routing of the rods and locations of bell-cranks due to the actual vehicle in question and body style and underfloor layout.

For instance the single level 4104, 4106 were fairly simple with a minimum of bell-cranks needed to change direction of the motion, and those are at the rear mounted to the firewall and take the motion from the centrally running rods and sending it to the two transmission shift levers. The two shift levers on the transmission each only control one of the internal shift rails. One is 1st-2nd gear and the other is 3rd-4th gear. The rods are connected to their respective shift lever and the motion is carried to the front.

Under the front shift tower below the floor is the mechanism for moving the two shift rods fore and aft. It's internal design is of two square blocks that move independently and attached to their respective rear headed shift rods. These blocks each have a square notch facing each other where the bottom of the shift lever has a heavy duty lug that moves from one to the other in neutral and once engaged in a block can move it either fore or aft. This is why the shift lever will feel very easy and tight to move in neutral yet can be very sloppy with lots of lost motion obvious when actually shifting into or out of a gear.

One area that can really cause a lot of lost motion is the shift tower itself and where it is bolted into the floor. If the bolts loosen up or the floor is rotted the tower will move and the critical pivot fulcrum point at the top will be moving around and not transferring the motion into the rods below the floor. I've experienced this first hand through the years with horribly maintained GMCs and the result can be to make shifting almost impossible. The trick is to flick the wrist when shifting and impart a large amount of initial high speed motion and let inertia take over to move the motion of the rods all the way to the rear.

Reverse is internally controlled by a third shift rail and inaccessible from the normal 1/2, 3/4 shift levers. So GMC devised the electric solenoid to pull the internal lug over into the 3rd reverse rail. This is accomplished with the driver putting it in 1st gear and then hitting the reverse switch/button and pulling it back into 2nd gear. This is the typical GMC manual transmission operation from the very earliest days.

You will be interested to know that to the maximum extent possible GMC designed their buses to use as many as possible common parts and similar overall engineering designs to keep manufacturing costs and bloated parts inventories down. From roughly the 4104/4106 designs they created the city transit models which were almost exactly the same below the floors as the highway buses. You'll find many interchangeable parts for your Fishbowl used in the 4104/4106 models. Main differences are the inline 6 vs the two V-6/8 engines and the design differences needed to operate them. This commonality of design philosophy was one of the many genius innovations GMC did. Many operators liked the overall designs and ease of maintaining the buses to keep them on the road and making money. Simple, easy to repair, and very reliable are all important to a for-profit operator.

You could replace the rods with cables for sure, but it won't be easy since you'll need to gain access to the underfloor tunnel the rods and other lines run through. That's not a normally accessible area and may promote some creative new expletives... Try to secure the front shift tower assembly if possible to the floor and continue to use the below floor shift block system. It's better to use this since it's real easy to attach any new cables to the blocks themselves in place of the current rods' clevis's. That's what I did on the Scenicruiser and it was an extremely simple process since the blocks already have mounting holes to accept the clevis pins.

Instead of going to all the trouble of installing cables you may find it fairly easy to locate the needed parts, bell-cranks, clevises, pins, possibly new or from another donor bus where they aren't so worn. Remember to look at highway buses since they will be very similar if not identical parts. Then make the effort to repair and tighten the front shift tower to the floor so it doesn't move at all. This will make a huge difference in the whole system response. It's an easily overlooked problem area.

Sorry for the length but I do get carried away sometimes trying to make myself clear on what I'm describing. Good luck and happy hunting.

you just described my shifting mechanism to an absolute T!! you rock!! right down to the electric reverse..



in my case i can see what you say about gaining access to the tunnel.. my air conditioning system is also under the floor and I really dont want to disturb the evaporator or the heater core as neither leak... ..


the shift tower does have some movement so I think plating it to secure it more will be in order.. theres some play in the bell cranks.. I figured on just turning and press fitting bushings in was going to be my play on fixing those.. might be easier if i can source NOS or good used ones.. considering I bhave to borrow a friend's lathe and press to make parts..



this is super information! thanks for posting.
-Christopher
cadillackid is offline   Reply With Quote
Old 02-21-2024, 05:40 PM   #14
Bus Nut
 
Crown_Guy's Avatar
 
Join Date: Dec 2013
Location: SoCal
Posts: 389
Year: 1989
Coachwork: Crown Coach
Chassis: 40ft 3-axle 10spd O/D, Factory A/C
Engine: 300hp Cummins 855
Rated Cap: 91
Those are all very good solutions. Installing bushings and new pins will make a big difference in the lost motion at the bell-cranks. You can easily find brand new clevis's in many sizes as well as pins today. Industrial suppliers carry them for sure. The bell-cranks are by definition somewhat custom in their design due to the application, but you should be able to repair and re-bush a bell-crank as long as there's enough material left to accept the bushing. Also be sure to check and verify that the rear firewall mountings for the bell-cranks are tight and secure. If that bracket assembly is loose where it bolts into the firewall it's the same as lost motion at the front shift tower. Keep in mind the overall goal of the system is to transmit as much motion as possible from the front tower to the transmission shift levers. Anything done to improve this and remove slop will have a beneficial affect.

All this easy to understand and easy to make field expedient fixes was always one of the major strengths of the overall GMC product lines. Remember they were designed and built in the late 40's for a country that had no interstates and lots of dirt roads still. Not very many sophisticated repair centers where parts were easily available. That's why they had oil bath air cleaners, replaceable canister oil filter elements, and most all the components on the bus were meant to be repairable by the local mechanic. Maybe crude looking to us today and very low tech, but it worked for the era and intended road and maintenance conditions of the day. You could almost always find a way to patch it and limp it into a better situation for proper repair.

This is very much the same way Crowns are built and why they are so beloved for the inherent over-engineering and simplicity of design and components used. GMC and Crowns can usually be relied upon to find a way to get you home, or at least to a safe harbor for repairs.
Crown_Guy is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 08:41 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.