| Author | Message | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: |
The two speed Rear End question pops up again... I have a '62 Crown /220 cummins /5spd Fuller. Top speed is 61 but only because the previous owner turned up the injection pump governor to 2500 RPM... ugh...not so good I'd think. The QUESTION... does anyone know if there's a 2 speed rear end that will fit into this bus? Or any better options? (I doubt larger diameter tires will change things as far as I probably need to go) Cheers! Gary | ||
| RJ Long (Rjlong) (24.127.8.58)
Rating: N/A |
Gary - Crown intelligently used off-the-shelf HD truck parts for their running gear. So you're rear axle is the same as many 18-wheelers. More than likely it's either an Eaton, Rockwell or Dana unit - you'll have to crawl underneath to find out, as there should be an ID plate somewhere near the pumpkin, which will have the manufacturer and maybe the ratio noted, or at least a serial number. Once you have this info, then you can visit your local HD truck boneyard and go traipsing thru all those rear ends to find one that will fit with a better ratio than what you currently have. (Remember: Larger ratio = better acceleration, slow top speed. Smaller ratio = slower acceleration, higher top speed, better fuel mileage. MCIs run 3.73s in the 8s & 9s, btw.) Most will not be worn out, many rigs are junked before the third member dies. So the boneyards have lots, reasonably priced. . . Don't know of any 2-spd rear ends built in the 20,000+ lb range, most were found on medium duty vehicles. Can be VERY scary when 2-spd splitter doesn't split on a downgrade and leaves you with NO ratio 'cause it's hung up between the two. BTDT - DON'T want to do it again. . . HTH, RJ PD4106-2784 Fresno CA | ||
| dougthebonifiedbusnut (24.218.119.24)
Rating: N/A |
hey gary i have been through were you are going and the answer is no there is no 2 speed that will fit into your carrier and besides a 2 speed will only cut every gear in half it will not give you any more speed i just put a set of 370's in my crown it is computed to go 78 at 2150 rpm am putting her on the road in may will give you more info then hey rj i think you said you have a 3 axle crown do you know what the weight rating is on those axles i thought they were 38k's you say they are lighter? | ||
| R.C.Bishop (128.123.88.46)
Rating: N/A |
Doug... I think RJL was refering to my 1964 Crown Highway Coach. Three axels, GVWR 38,500. With Seats was 28,465+- ( I don't have the exact in front of me just now)but after seats and luggage racks, spare, and all the junk in the bays, etc were removed, we weighed 23700 at a portable HP station. (see thread about added weight) RCB | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Cool. I grokked my rear end today and it's 5.29 ugh... but today I found a 10 spd Road Ranger that has a .81 overdrive, so maybe that will fix everything. The two together calc out at 4.28, giving me 61mph at 2100 Rpm and 74 mph at 2500...I'd think that's good enough for me. It's an RT 910...anyone know how easy it will be to drop in? I'ts 6" longer than my Fuller 5C72 so the drive shaft will have to be cut... hope the increased angle doesnt mess with the U joint bearings too much...but I'm wondering what bugs I'll run into in the clutch area.... ...and Hey, is that Road Ranger a crash-box or do they have synchros? Gary | ||
| jdexsquid (216.175.71.48)
Rating: N/A |
I have a Crown with a similar setup, only my gear ratio is 4:63. It'll run 60 @ 2250 rpm. 2500 rpm is really making that Cummins scream! This is just me, but I'd put a 3:70 in there first. I feel this would give you the most bang for the buck, and by far the easiest swap. I have a 3:70 I'm about to swap in...I'll let you know how it goes. As you've read, dougthebunifiedbusnut has already done this. Be careful with the RT910 swap...I was and may still do the swap, but where your 5 speed E/F is a plain old manual unit, the 10 speed is air powered. You'll need an offset shift tower like you'd find in a cabover truck. You will also need to shorten the driveshaft. Small stuff would be running air lines from the gearshift to the tranny. I hope this helps! Jim | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Thanks Jim, I think I'll forge ahead with the Eaton. I have a pretty complete machine shop at home and also access to some big machine shops. The only scary thing to me is how to actually get the bugger in and out without getting squished!!  To do the rear gears costs about as much as the 10 spd I found, and then I'd still have only the 5 speeds, which have already bunmmed me out on the I-5 grapevine. I can always do it later... The big unanswered question to me is about the shorter driveshaft, and whether the increased angle will kill the U joints or not. If this is the same setup as was origionally an option from Crown, I guess it'll work fine. Yep, 2500 is too fast...but someone turned up the injector pump before me and it hasn't blown up yet... who knows! I think 2500's fine for passing but not like the origional drive home where I unknowingly ran it at 2500 for 8 hours straight!! ( The tach wasn't working when I got the bus... it certainly is now!!) Cheers! Gary | ||
| John the busboy (12.73.163.194)
Rating: N/A |
There is the 11605 Eaton which is a 5 speed and does come in a variety of gear ratios including overdrive ratios. If you don't like the gears you wind up with you can always have it regeared. The Eaton web site used to allow one to download service manuals. John the busboy | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A |
Hello Gary; My '74 Crown 10-wheeler has the RTO-910 10 speed with 3.9 drivers. Best of both worlds. I am lucky. Will go 80 at 2100 in 10th, which is a 22% overdrive. (.82) The Roadranger is a crash box, but with just a little practice, you will do fine. I have. More like shifting a motorcycle than a bus. Broom, broom, broom, snick, snick, snick!!! Wow!! 28.5%, 26% and 22% drops. Very close together. The Roadranger is soossss cool. The bummer is that it will be difficult but not impossible to install. Lots of stuff will have to be changed out. Drive shaft, shifter, running an air line, trans mounts, etc., etc.. Sorry to say if you just need more MPH, changing out the case in the rear end will be MUCH easier and cheaper. Your 5 speed has plenty of low gears to start your Crown. The choice is yours. If it were me, I would decide what YOU WANT....then go for it, regardless of the time and expense. Thanks CROWNS FOREVER!!! henryofcj@hotmail.com | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
HI Henry, Thanks for the thoughts, but it's waaay hindsight now. It took me a week of messing around, shortning the driveshaft, redrilling the flywheel, changing out the shift lever mechanism, chasing seemingly endless clutch incompatibility issues, and shortning the shift tower on the tranny, but at this point I can happily say that my bus has a nice freshly rebuilt Eaton 13609RTX dual-countershaft 9 speed with .72 overdrive (and a normal shift pattern!!) so I'm set. In the swap, I redrilled my flywheel to accept a Lipe 2 plate "ceramic puck" "pull" type clutch kit...boy, now it's easier to press the pedal than on my Honda Accura!! And with the changeout of the crown shift mechanism to a modern type, the shift pattern is sooooo tight now... only occupies about 8 square inches in air-space at the shift-knob as opposed to the two feet or so that I had to move the old one. The tranny itself just "bolted in" although the clutch was a bit of a quest. Regular Cummins 2 plate style flywheels are an inch offset at the ring gear and whack into the pancake engine housing. The flat flywheel that came with my bus had the wrong drill pattern for any other clutch type, and it's ID is too big for most clutches. I ended up with the pucks from one plate underhanging (in air) about 1/2 inch, but it's my opinion (and that of a professional clutch rebuilding house) that it won't matter, because my bus is around 30,000 pounds and I'll drive it 6-8 times per year, while the clutch is made for an 80,000 pound vehicle running daily... it will wear funny but not before I'm long dead and gone will it need replacing. And the offset shift tower of the 9 spd origionally hit my frame so I had to cut it shorter by an inch...that was a fun one.... but all in all it was a great swap, I'd do it again. Changing out the pumpkin would have cost more than this swap so I'm very much ahead in the game!! ******* Re the roof raise, yes on the insulation, I've got about 3-4" space up there that I'm going to foam. Then put T&G Cedar on as my finish for the inside. It was quite a job but nothing was difficult...just took a lot of time and thinking. I'd definitely do it again...a tall roof leaves SOOO many possibilities, plus it feels nice in there becasue of the nice headroom! Cheers Gary |
