As stated,...the trouble is the shift rod linkage is no where near lining up, and there is precious little room to do anything about it. I have been driving this MC-2(1961) for 30 years. Replacing the 6v71 with a 6v92. The 6v92 (270hp Ca eng) came with a Fuller 11605 attached (all out of an 1983 MC-9 I bought for 2 grand). The Spicer 6454 is only rated at 550-600 lbs torque or I would use it. Just wondering if there are any tricks or mechanism for adapting the Fuller. The Fuller shift rod shaft on the trans is 4-5" offset (at about the 8 o'clock position) from the MC-2 shift rod end which is a ujoint. What is even more problematic is they bypass one another by about 4". I have tried using a 3x6x1/4" plate to connect the two which may have worked if the two shafts were directly above or below one another (6 or 12 o'clock) but won't work at 8 o'clock to accomplish the needed side to side motion. Does fuller have remote housings of different dimensions? I haven't been able to find any info online. Sorry this sounds confusing, but tips would be appreciated. Somewhere in the future may be a 644 or 647 Allison, but for now want to solve this. Thanks....Brian R.
Will be junking the MC-9...baggage doors, etc.
Use short cables with brackets to hold the cables in place to line up and connect to your existing shifter rods
Thanks for the info Luvrbus,...I will have to go to school on this....Brian R.
You see a lot of transmissions with cable,that is a single shaft shift tower right ?
Putting in a short length of Teleflex or CableCraft push-pull cables can be a very good solution. Modify as needed to transfer the motion into the new transmission. The cable designs today can be had with internal Teflon surfaces to reduce friction and the lost motion from end to end is almost negligible.
Many, many years ago I drove with a friend and his MC2 with 6V-71 to Cabo San Lucas right after the new road was opened in 1972. I remember that it had a 5spd transmission and the twist and push-pull single torque rod style linkage. All this to engage the 3 shift rails in the transmission to do the 5 speeds and reverse. This is exactly the system used by all Crowns since 5spd Fuller was standard, and why it's so simple to upgrade/replace with a RoadRanger 10-spd etc. The linkage is already there and will accept anybody's multi-gear transmission. Crowns are very easy in this regard, unlike most coaches with the simple, but limited to 4-speeds, and electric solenoid reverse, twin push pull rods and bell-cranks as used in GMC and MCI. Prevost did tend to have the single shaft torque rod design so they were fairly easy to upgrade as well, much like Crowns.
I completely replaced the original twin push-pull rod/cable/bell-crank GMC system in my Scenicruiser with a pair of CableCraft Teflon interior push-pull cables. Very easy and simple to do. All the way from the under-floor shifting tower connections to the two levers on the Spicer 44?? transmission so common in use in all coaches, about 30 feet. When finished the shifting effort was almost nonexistent, so smooth and friction-less with no apparent lost motion. It was so good I started to shift without the clutch and floating the gears, with two fingers, that's all the effort needed. Anyone who has experienced the typical GMC shift linkage deterioration, with age and abuse, issues will appreciate what I'm saying. Way better than new even. It's a real good solution open to anyone fighting with the GMC-MCI linkages falling apart.
You should be able to engineer and modify your linkage near the transmission end to transfer the motion without too much trouble. The cables are typically custom made with differing lengths, design enhancements, and end hardware to match whatever you're connecting to. Don't expect to find a part number solution. This is pure custom work, but any, and I mean ANY proper Teleflex or CableCraft distributor/shop will have the expertise and tooling to fabricate exactly what you need. That's how you do it. And it's not terribly expensive at all. They can give you the details on how to request and spec. out what you need fabricated.
Thanks for the encouragement guys. I wasn't aware of cable systems for manual shifting but see lots online for cars. And I now see Cablecraft has complete front to back systems for trucks and buses.
This Fuller trans has a single shift rod near the top and on the side of the trans.( as opposed to a truck style that comes straight out of the top,...but you guys already would know that) It is a funky inverted "L" shape about a foot long with a heim joint near the center which attaches it to the trans. The short end of the "L" is attached to a stabilizer bar that allows for movement as it is has pivots( ball joints) on each end. So much for a useless description, lol.
So I'm busy trying to figure how to arrange two cables to allow the necessary front to back motion and the side to side motion without the two cables binding as it seems they would have be able to bend sideways perhaps an inch or so (from a nuetral setting) to reach all the positions. I think I will go to a cable shop to see what they think about it, maybe it is not a problem.
That is very nice outcome for you Scenicruiser Crown Guy, sounds super slick and easy. Probably took 40 years off her. I always loved the look of the Scenicruisers.
Dumb question time: This 6v92 is a 270 hp tta Calif. cert. Fed engine and I am fine with that. But I surmised that the torque rating would drop with the hp rating. So I looked up what I could and it seems it doesn't work that way as what I saw said the torque was still up around 800-900lbs?? The 11605 Fuller is rated at 1100 lbs which is dandy. The Spicer 6454 that I have is about 600lbs torque. A mechanic in Oregon I spoke with some time past thought I could probably get away with using the Spicer on the 6v92 if I was good to it Any thoughts about that? Thanks for the help .....Cheers,.....Brian R.
To add a note....to address the side to side bending of the cables I've come up with the idea of making cable mounts that can swivel. Haven't found any available online so I will make simple ones. Shouldn't be too hard. I will need four. (Two cables, four ends)
Quote from: Brian R. on March 12, 2023, 02:41:42 PM
To add a note....to address the side to side bending of the cables I've come up with the idea of making cable mounts that can swivel. Haven't found any available online so I will make simple ones. Shouldn't be too hard. I will need four. (Two cables, four ends)
You should be able to find something that works on www.lexcocable.com or they can tell you to get it
Thanks again,...good site....Brian R.
A friend of mine had a '63 Eagle that he retrofitted with a Cummins. I don't recall the size of the Cummins, but it was very impressive. He retrofitted a Fuller 10 speed into it as well, and changed the rear end ratios, etc. That being said, he constructed some kind of linkage that would otherwise be backwards shifting (from the driver's perspective, with the engine and transmission being at the rear). I didn't actually see it and it's all history now, but he was saying that he considered getting a patent on the reverse shifting mechanism that he built. I know this doesn't add to the conversation, but it was interesting at the time.
When old busnuts retrofitted multi-speed transmissions, the slick ones used the shift hardware from a cab-over to turn everything around again, so there was a traditional pattern up front.
No clue what truck to pursue for parts...
Happy coaching!
Buswarrior
Some mounted the shifter on the left side of the driver
I am running a spicer shift cover on a fuller 10spd might be a option, requires a 1'' spacer. 1977 Eagle
Brain R Take a look at a 80's Kenworth cabover truck. They used a cable system to shift the trans in them. Most ran Fuller trans. You might be able to used the shift tower off the trans and the shifter box and just have new longer cables made.
Years ago I installed a 10 speed Road Ranger from a cab over White 7000 with the air shifter, the only problem with the air shift was you could bump it and the thing would jump in gear with the engine running without the clutch being depressed.
Lots of interesting ideas. Too much rain here so still investigating bracket location feasibility for cables to mount. The available space in there is very limited. I already sawed a 6x18x30" hole in my floor to make room for the turbo on the 6v92. Good thing is I have the engine on a pallet lift and can roll it in and out in a couple of minutes.
The plate I made to attach the bus trans rod to the trans trans rod ( which din't work out ) would also have created a backwards shift pattern, as my smart son pointed out to my in the design stage. I would have been ok with it,...sort of novel.
I'm surprized the Spicer shift cover fit on the Fuller ( some kind of commonality of parts?) I may look into that,..talk to a savvy old trans guy at a trans shop, if there still are any.( Bernie at B&B in Rialto,Ca is long gone.
While I'm at I'll try to find a 80's Kenworth cabover for a look see there.
You can't hurry love but one thing that bugs me about the bus being out of commission for over a year is a year off the dang tire life. They are so(!) expensive now. Cheers,...Brian R.
Not even close to a direct replacement, but can be made to work. As I said it requires a 1'' spacer mounted to trans and holes drilled to mount the cover.
I used the shift cover and the trans cover from a Eagle factory installed cable shift set up. I used the 2 rod set up for my 4spd and used ball joints to hook it all to together. Good luck Bob