Different question: replace tranny?

[Sean]

As I detailed in the other thread, we have decided to stick with our original, low-mileage 8V92TA once we replace the leaky end-plate gasket.  We'll go over the whole engine before putting it back in and address any other leaks or issues.

There were lots of reasons to look at a different engine.  Our mileage could be improved, and our speed up hills right now is limited not by horsepower, but by heat dissipation (I have to slow down and downshift to keep the temperature in the green).  The ISL, at 10% less horsepower, would still give us a faster uphill speed.  But I digress...

Given that we are keeping the 475-horse, electronically controlled 8V92TA, should we think about upgrading our transmission?

Today we have the Allison HTB-748, an electronically controlled (CEC-1, aka ATEC) four-speed with a top gear ratio of 1:1.  With our 4.3 rear end ratio, that gives us a top speed around 70mph with the Detroit screaming for its life.  55mph, which was the national limit when this bus was made, is comfortable.  65 is hard on everything.

I am wondering if a B500 or a 4000 MH would make more sense for us, and whether a good used one could be had, with trade, for a reasonable price.  What issues would I have mating it up to the Detroit?  Is a retarder available with either of these models?  Lastly, does anyone have a source for a nice take-out, preferably close to Chattanooga?

Thanks again for all the advice and assistance.

-Sean
http://OurOdyssey.BlogSpot.com

[luvrbus]

Does your Neo have a ZF drive axle ? may be a lot cheaper to call Global Gear and change the ratio in the rear installing a 3:70 would make a huge difference and still have power your engine should have 1500 lbs of torque at 1300 rpm if not we can fix that buddy lol

good luck

[Hal]

Sean, the worlds are great transmissions and your gear ratio will probably work.  You might end up in 5th gear more often than not with the lower torque of the two stroke but you'll certainly give the motor a breather at the lower speeds it'll see. You'd probably see a good mile per gallon better milage running it the same speeds. Any of the big worlds should work for you, B500, 4060 or the 4560-maybe even the best for your application. The 4560 has a little deeper ratio most of the way through 6th where it has a .67 vs the others .64  overdrive ratio. It just needs the bus programming to work right-shifts like a car-total different feel from your hyd trans. They can be had with the retarders also. Try to find one with the harness, ECU, and shifter. Finding the parts separately can be pricey and difficult.There were three different pan sizes available so you'll have to check your clearance. The interface is simple with your DDEC, J1739 if memory serves. The trans' are available and the prices seem to have come down a lot over the last few years.
Good luck, Hal

[robertglines1]

Question with the 4:30 ratio what rpm @70 mph are you turning the 8v-92          What rpm is your sweet spot?    Bob

[luvrbus]

Sean, I see if I can find a number for Pacific Powershift in WA state they had great buys on new B500's last year with no core charge 

good luck

[Busted Knuckle]

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&_trksid=p4340.m748&item=260804564445&viewitem=&_trkparms=clkid%3D977736980886225412

http://cgi.ebay.com/ebaymotors/Allison-transmission-4060-World-6sp-Eagle-Mci-Prevost-/180684983914?pt=Buses&hash=item2a11aa0e6a

Or you buy a re-manned unit from WW Williams for $8000 or less and they build them down in Columbus, GA!

Best option would be to buy a wrecked or rusted/rotted out bus with what ya want and drive it to the Choo-Choo and rob all the stuff ya need for the swap off it like trans, comptuer, wiring harness, shift pad, cooler? and maybe even an air to air charger and plumbing to set up for your existing turbo/engine. (cooler air = more power @ less temps)

Then let Joel & Mr. Bowen scrap the rest of it (for whatever type of arrangement ya'll come too)
 BK  

[robertglines1]

FYWI prevo runs a 4:56 Rear with their world trans in shells and 4:88 in coaches. 315 80r 22.5 tires :::  I'm using 4:56 With 10spd eaton autoshift in 98 behind 60 serries

[Boomer]

There are 4060's and B500 for sale on ebay........

[Sean]

Thanks, everyone.  I think I need to go measure the rear end ratio.

The rear end is a Mercedes, not a ZF.  Too bad, really, because I can't get parts on this side of the pond; when I needed to replace the pinion seal I had to order it from Germany.  According to my Neoplan parts book, it is a 4.3, and that's what I programmed into my ECM, along with the tire rpm (480 for my Bridgestones) to get a correct speed display on the Silverleaf.  The display is dead on with these settings, per my GPS.  However, some notes I have here about RPM readings from the Silverleaf at various speeds would calculate out to a 3.7 ratio.  But if I put a 3.7 ratio into the ECM for the VSS calcs, the speed reading will be incorrect.

Something doesn't add up and I need to get to the bottom of it.  With the powertrain out, I can just jack up one set of drive wheels and spin them around half a turn while counting drive shaft revs.  At least in theory.

I'll try to get this done tomorrow, since I certainly don't want to be buying transmissions without knowing what the ratio really is.

-Sean
http://OurOdyssey.BlogSpot.com

[HB of CJ]

Keep the engineered configeration you have, only hop up your mighty Detroit to 550+hp, increase your radiator and air charge cooler capacity and then change your diff gears to 3.70's?  This idea might be the easiest as nothing is changed out.

How much torque can the 740 platform handle intermidentlly? (sp)  Can this tranny be beefed up kinda?  Sounds like once you are up to speed, everything is hunkydorry otherwise.  Darn the mpg...cruise at warp 7.0.  HB of CJ (old coot)

[robertglines1]

On my 8-v92 my sweet spot(best fuel&performance) is about 1850 rpm.  @ 2150 my speed is 72mph for what it's worth.

[luvrbus]

I always ran 3:33 or 3:36 gears with my 8v92 makes for a nice set up with good fuel mileage made 3rd wicked with the FS 740 Allison.I got the same fuel mileage as most Eagles with series 60 and 10 speeds little over 7  like Jim has .
I did a lot better than the guys with ISM and series 60 with a 740 and the drop box setup those guys were a pain to travel with running 50 and 55 mph to achieve 7 mpg
You have 3:73 rear gears Bob  

good luck

[TomC]

If I had your bus, and with what I've read about you getting stuck or close to stuck a few times because of startability, I'd stay with whatever rear end ratio you have.  The B500/HD4060/4000 series all have just about the same gear ratios of your HT740 for the first four gears (3.51 vs 3.692 on your HT740) with the addition of two overdrives of .74 and .64.  The HD4560/4500 series is a wide ratio with a 4.70 first and closer ratios on the overdrive of .76 and .67.  The disadvantage of the 4500 series is it shifts a bit harder between 2nd and 3rd, 3rd and 4th since the ratios are also wider.

If you want to just about completely eliminate your heating and hill performance issues, increase your fuel mileage and get maximum performance out of your bus, but with slower acceleration from a stop, look into using an Eaton 10 or 13 spd UltraShift Plus.  These are regular truck transmissions where they have literally taken the gear shift lever out and replaced the shifter with two electric motor shifters working through a computer that also talks to the engine computer.  The first series was called an Autoshift that used a traditional clutch for starting and stopping only.  I'm sure you don't want to get into installing a clutch (although a hydraulic clutch stollen out of Freightliner truck would make installation easier).  The second version was the UltraShift that uses a centrifugal clutch that I wouldn't suggest since the clutch only lasts about 100,000 miles since it never really fully engages.  The current is the UltraShift Plus that uses a regular clutch that is electronically controlled.  Both the B500/4000 series Allison and the 13 spd UltraShift Plus weigh about the same with the 10 spd UltraShift Plus about 50lbs less. 13spd has a .86 and .73 overdrive, the 10spd has either a .75 on the B model, and a .74 on the C model (B model being a close ratio with 11.1 to one first [more then enough for you] and the C model with 12.43 to one first).  The only real issue that people don't like about these transmissions is that they are slow off the line (they are automatic shifting manual transmissions) and you can feel each shift.  But you also eliminate about 5,000btu/minute heat from the Allison since they only need a small air to oil cooler, and they are the most fuel efficient.  The 13spd has all top 4 gears being able to be split by the overdrive splitter, so you have 8spds very close together for highway use.  Personally-I still love Allisons.  Good Luck, TomC

[desi arnaz]

off topic a little  but you said when you went to chew-chew you were expecting a bill of $6000 or so,   what roughly was the final tally? i was just wondering in case i need some work done as it might be worth the detour.

[Busted Knuckle]

off topic a little  but you said when you went to chew-chew you were expecting a bill of $6000 or so,   what roughly was the final tally? i was just wondering in case i need some work done as it might be worth the detour.

Well Dezi,
They ain't done eat'n yet and so they hadn't chewed the final bill.
They are still in Chattanooga @ the Choo-Choo Garage working on it and Sean is seeking other options whilst the Choo-Choo garage continues to fix the original problem.
  BK