Allison Transmissions Difference ?

[luvrbus]

Which is better the 4000MH or the B500 Allison ?

[Zeroclearance]

Clifford, I think that you need to look at the miles in service and the weight of the buses.   I think the best World is the trash truck box...   Or having a B500 built with some of those internal parts..   I was at the dealer and talked to one of the box builders and he said that there are many updates!

[wg4t50]

Have the 4000MHR with the ISM500 Cummins, after 106,000 miles and two pil changes with the Alluson Synthetic (forgot the name) & filters, it acts just lije when new, zero issues, No idea about the B500.  I do not use the ECON mode and I generally push it hard. If it crapps out, will get it fixed.  Expect the ISM to show issues first, but it also keeps going fine. 
Will not run with a strung out 8V-92 (600+hp), but does not burn any oil.
Would prefer a ISX800 but no auto for it yet.
Dave M

[TomC]

The only difference between the B500 and the 4000MH or 4000HS is the depth of the oil pan. There are three available oil pans. Typically the truck version, the 4000HS or 4000RDS (with PTO) will have the deepest oil pan. The B500 will have the smallest or most shallow. This means it is less tolerant to low fluid levels. At minimum, the B500 should have the fluid level checked weekly if not daily. All of the World transmission big case 4000 series are the same inside. Good Luck, TomC

[luvrbus]

There has to be some other difference in the 2 the reason I asked my doctors last Prevost had a 4000MH Allison his new H-45 he ordered it with the B500 because of problems with his prior 4000MH

I just trying to find out why Prevost only offers the 4000MH in the conversion shells as standard equipment and the B500 is offered in commercial use not the 4000MH ? ,looking at parts numbers there are a lot of different part numbers for the inside of B500 and not so much with the 4000MH

good luck

[TomC]

The B500 and 4000 series uses the same box. As was explained to me by my Allison factory rep, there might be some differences in the components-mainly clutch materials, spring rates, programming etc. Allison rates the transmissions according to duty cycle to get the longest life out of the transmissions. For instance:
B500- 500hp and 1700 torque with either a 48qt or 40qt oil pan
4000MH- 650hp and 1950 torque with either a 48qt or 40qt oil pan
4000HS- 560hp and 1770 torque till 3rd gear then 1850 torque available through 6th gear with only 48qt pan.
Allison also makes the 4500 series wide ratio and the 4700 series which is the close ratio 4000 series with an extra low gear-mainly for heavy haul trucking.
From the ratings, you can see why Prevost would use the 4000MH on the conversion shells compared to using the B500 on commercial buses. Transit buses are rated even less. Good Luck, TomC

[wg4t50]

Thanks for info, my 4000MHR should be the deeper pan due to the retarder, it takes lil over 10 gal to change w/filters.
With the Silverleaf VMSpc, keep eye on both sump and retarder temps.  The retarder temp can go way up quickly, so keep eye on it along with gear/rpm going down long steeper grades.  Works great and seldom need the disk brakes. Over 100 K miles, pads & rotors look new.  The only down side of the Meritor Disk Brake setup, I do the annual R&R check, clean & dry silicone spray on the caliper slide pins, also do the PM on caliper & auto slack adjusters.
It does stop nearly like a car.
The old days of S Cams & drums are simpler, cheaper and less effective.
So picture the Retarder with 2,000 ft lb  restriction on drive shaft and the disk setup, dry road only. rear engines will swap ends speedo.
Dave M

[Don Fairchild]

Clifford, the 4000/B500 is the same basic transmission, the B500 has a shallow oil pan and most of the 4000 have a deep pan. You will find this out the first time you change the oil. The up dates talked about deal with 3rd 4th and 5th gen controls alone with a new wire harness, improved valves and valve body, oil level sensor, new clutch plate material. You need the serial number as always to know which TC ration you have and weather it is a close or wide ratio trans. By the way according to the book it is that same as the HD 4060 they just changed the numbers to tell the service and parts people what they were working with.

Hope this helps

Don

[luvrbus]

Why does Prevost offer both transmissions with the same engine, same HP rating ,same torque lbs rating ? same GVW and the B500 costs more as a option almost 3 grand more

[hargreaves]

Cliff  does the B500 come with a retarder?

[luvrbus]

No Gary he has the Volvo engine brakes with the B500 his 4000 had a retarder and he didn't want that set up again

[TomC]

With the new Detroit DD engines, the Jake brake is built in. You only have a choice whether it be turned on or off. When a Jake brake is built into an engine (it is still optional on the Cummins engines-except ISX15 where it is also built into the engine), then the Allison transmission retarder is not allowed-too much drive line braking. Good Luck, TomC