10 spd or 13?

[Uglydog56]

Hello!  I just picked up a 67 crown rv conversion.  It currently has a 220 cummins and a 5 speed in it.  I need a few more gears, and a few more mph, so I'm looking for an rto trans.  I thought the 13 spd with its narrow splits on top might be the better choice but I was hoping for some input from people who have driven both before I laid down the cash.  Thanks!

[opus]

I would imagine an RTO9513 ought to be real cheap by now.

[GilligCrown]

And if it were not complicated enough already, I'm told an RT non-overdrive can be converted to an RTO(verdrive), but the shift pattern is altered.  My Crown has a DD 6-71 turbo, RT-11610, with believed-to-be 4.10:1 rear end(s).  1st and 2nd gears are useless except for steep driveways, and it cruises at about 63mph @ 2100 rpm, though the engine will spin a bit faster.  I'll track down and forward some Excel spreadsheets with trans and rear-end ratios, tire circumference, and speeds in gears if you are interested.

On a similar note, CrownCoachJunkies "dukeofmagnolia" in Bremerton may still have a tandem Crown with the 855 Cummins and a 10-speed (I suspect non-RTO) available "on-the-cheap".  I'd be jumping at that if not for upcoming wedding expenses . . . 

Paul in Phelan

[opus]

Bus....wedding....bus....wedding....bus....oh forget it. 

[GilligCrown]

Some disillusioned folks would say to "go for the bus" 

[HB of CJ]

But not the 13 speed which is about 2.5 to 3.5 inches (forgot....some help here please) LONGER than the famous/infamous RT910/RTO910/RTOO910 close ratio, non synkro, heavy duty, (950 ft lbs low side-1500+ ft lbs hi side) easy shifting, bitchin 10 speed Roadranger.  A 13 speed will fit, but makes the drive shaft just a bit toos short.

My 1974 Crown (37317) had the RTO910 and 3.90 gears and would go an honest 82 mph or sosss at 2100 in 10th.  Cummins small cam 855 250 hp.  Normal starts were in 2nd gear and at 55 mph the coach would run either in 8th, 9th or 10th. Tenth with no head or side wind on level ground.  2165 in 8th, 1722 in 9th, about 1400 in 10th.

One concern would be that I think (not sures) that the Spicer 5 speed has two (2) shift rods while the Fullers (any model) have only one shift rod/tube that twists as well as moves forward and back.  However, converting your Spicer to a Fuller has been done before on Crowns sosss I'm sure you could do it.

My Roadranger shift lever moved about one inch or sooss and took about 3 to 5 pounds of effort to shift gears.  Non synkro for sures, but once you got the hang of it shifting soss quick, it became more shifting some dirt bike rather than a truck tranny.  Very easy to do.  Even 18 year old girls learned how quite easily.  HB of CJ (old coot)

[HB of CJ]

If you don't want to go to the little work and some trouble of running a dedicated air line from the shifter to the tranny tower, (Roadrangers require an air line for the range shift) and if you want to keep your already short driveshaft as long as possible, other Fuller trannys will also fit into your mighty Crown Supercoach RV conversion.

Fuller made lots of older model 6 speeds, one model which had about a 32% overdrive 6th gear.  Current Fuller 7 speeds include the nice RT14507 overdrive model which has a 33% overdrive 7th gear and would be nearly perfect with a high powered Crown.  I don't know what your Cummins is other than it may be the older 743 inch 220 Cummins which is a fine older engine.

If you only have the 220, (nothing wrong with that power) then a 10 speed Roadranger is what you want.  He he he, I love a good plan.  The famous/infamous RTO910 Fuller has a 22% od and the rare FACTORY RTOO910 has a 26% od in 9th and an ADDITIONAL 22% od in 10th.  8th gear is direct.  You can easily do the math.  A 220 in a Crown will give you an honest 70 to 75 mph top speed.  Very aerodynamic body.  More to come.  HB of CJ

[Uglydog56]

It has a single shift rod T905 fuller in it currently.  I've got a driveshaft guy, so not concerned about that aspect.  I'm not afraid of a little chopping, cutting and welding.  More wondering about the larger rpm drops with the 10 speed and how that corresponds to real life - is it really a concern?

gilligcrown, I have looked at Greg's 10-wheeler, and I'm trying really hard not make him an offer on it to get the engine/trans.  I have terminal "while you're in there" disease, and I'm sure I'd end up with a 600hp compound turbo nitroused propaned monster that would be the first one to the top of the hill and right into the gas station on the other side.   I'm attempting to grow up a little and be content with the 220.  But don't think I don't wonder at weak moments just how much ground clearance you lose with the 855 and if I could live with it, and don't think I haven't searched "cummins big cam" on ebay and craigslist either.

[bobofthenorth]

FWIW IMO the 10 spd RR is your most bullet proof easiest shifting option.  In a typical run up through "all" the gears I will use at most 8 out of the 10 I have available.  More typically I use 7 of them on the way up and maybe 4 or 5 when downshifting.

[RJ]

Rick -

IMHO, the basic 5-spd patterned 10-spd RoadRanger is somewhat overkill in a bus, but a SWEET transmission anyway!  Very easy shifting, lots of gears to play with depending on the conditions, and a "pain in the butt" while navigating Los Angeles traffic!

Start in 2nd, then to 4th, pull the button and from 6th on, have fun!

While putting myself thru college, I drove both Crowns & Gilligs with these - 90% of the time shifted like a 5-spd (2, 4, 6, 8, 10), loaded or empty.  Unless it was the HS football team plus gear going to one of the mountain schools for a game, then it was 1,3, 5, 7, 9, 10.

We even had a couple of 40-foot Gillig tandem pushers with this gearbox - no problem, except the shift pattern was backwards!  Great fun to send a newbie out and conveniently "forget" to remind them about this minor detail. . . veteran drivers can be cruel to the new guys!

Bottom line - they came from the factory so equipped, so go for it!

But stay away from 13, 15 or 18 - way, way too much for your application.

FWIW & HTH. . .

[opus]

I'd gladly trade my 643 for a RR!

[TomC]

While a 10 spd overdrive will be more than enough gearing for your Crown, I personally hate the 10spds.  The 5 spd repeat shifting, specifically going from 5th, making the up over and down "U" shift back to the 1st position for 6th gear is a big pain.  I would look for a 9 spd overdrive instead.  Still more than enough gears and, except if you use granny 1st, 2nd through 9th is just a repeat simple H pattern.  I had a truck with a B model 9spd that my driver was more then happy with the trans-so happy he bought the truck from me.
What you should look for is a RTO-12509B.  Then if you bump your Cummins up to 400hp, you'll have enough transmission to handle it.  And the 9spd is the same size as the 10spd.
As previously stated, the overdrive 7spd is another good way to go-then you don't have to deal with any air lines for the range shifter.
Good Luck, TomC

[joel_newton]

Retired truck driver.  Spent lots of time on 9, 10 and 13 speed transmissions.  I too dislike the ten speed pattern.  My right shoulder is worn out from those things.  Loved the 9/13s.  You can shift them in your sleep - not that you ever doze while driving!  Just bought a 1969 Gillig three axle with a RR RTO915 with a 260 HP Cummins (220 turbo), air suspension.  It has 95,000 miles.  It was converted when new to a grip equipment bus for Paramount Studios. It is perfect for converting to a motorhome.

To the point - I STILL sometimes forget the darn reverse pattern of the OD transmission.  Backing was a joke too when I got it.  It kept turning the wrong way. Oh, that's right, no trailer.  Old habits die hard!

Wouldn't mind finding a Cummins 855 either.  It was one of the Gillig options.  I am told the pan from the 743 will fit the 855.

Anyone know if the shift linkage can be shortened?

[Bob Belter]

Ahoy, Uglydog,

In my Eagle-01, I have an M11 Cummins with an RTO1110. 

The Transmission was anRT1110, and I converted it myself, by swapping gears -- NO new gears.  I have a 30 ton press, which would not unstack the gears, and went to a shop with a bigger one.  A regular tranny shop guy patted me on my head, and told me that I would need lottsa new gears, but another shop (my guru) told me that he had done it often  --  was correct.   Now ~~65,000 (new) miles on the box.    Works great.

No problem doing the job, other than being careful not to lose a lot of fingers in the process.  The manual talks a lot about 'timing', but my guru said to pay attention, but that it was very difficult to get it together out of time, and if you managed to, it would not rotate.

Driving it with a very quick electronic engine was not easy.   People would hear me shift that sucker, and would wonder how I ever managed to land a jet on an aircraft carrier.   

I collaborated with a friend, and we have created a synchro system which really works great.  I'd guess that I'm driving the only ten speed synchro transmission in the world.  I designed a 'map' of speeds/gears to be in.  He set up a PLC (Programmable Logic Controller), and display of the gear target, so that when I pull the trigger on the shifter, it gooses the engine to sync.  Just pull it into the gear.  My normal shift on the flat, and warmed up is 1,3,5,7,9,10.  Very slow on hills where I cannot achieve doubles.

Sooooo  we said  "Maybe not rich, but less poor".  Floated the scheme, and bus, to Williams Controls in Portland.  They make the electronic engine 'foot throttles'.  They loved it  -  but only for a little while.  They found that there are very few trucks being built, other than the 18 wheel tractors, which are not automated.  This thing does not lend itself too well to the individual installation  --  Too much programming, such that an AutoShift would be more appropriate.  My M-11 does not have the SAE 1939 protocol plug, so the AutoShift was not an option for me.
Soooo   --- We simply had  automated the buggy whip, but I'm very pleased with it, and now even have 100% spares aboard. 

Good luck   /s/   Bob

[Mex-Busnut]

Might one of you fine gentlemen tranny gurus know the gear ratios of the Rockwell model 166-09 nine-speed tranny? I learned to detest my Spicer Super Ten real quick, espescially for down-shifting on mountains, and my diesel mechanic insisted this Rockwell would be the cat's meow for me. It is already installed. Have not been on the highway with the new tranny yet.