OD ratio in Auto Trans? And where to find spec sheets.

[BavarianE31]

Wondering what the gear ratios are for post-lift BMW E39s are. Some websites say 5th gear is 1:1 but others have it listed as 0.87:1? I always assumed that the AT equipped E39s didn't have overdrive, but seems like 528i's do? Little confused here. I'm looking at a 2002 530i and the spec sheets says "5 speed w/ OD".... What's up with that?

And lastly, is there a source for ALL of the options available for the E39? I'm looking for an inclusive options list with prices like the one that comes from the dealer, where it lists out packages, prices and itemizes them neatly:

Included Optional Equipment

PREMIUM PKG[ZPP]

Original Price:$1550.00
Details:
Passenger Lumbar
Electrochromic rearview mirror
Driver Lumbar
Onboard Hands-Free Communications System
Wireless Cell Phone Hookup
Universal Garage Door Opener


COMFORT ACCESS SYSTEM W/COMFORT LOAD[322]

Original Price:$500.00
Details:
Keyless Entry
Keyless Start
Vehicle Anti-Theft System
Power Door Locks





DVD-BASED NAVIGATION SYSTEM[609]

Original Price:$2100.00
Details:
Navigation System
CD Player
DVD Player
Trip Computer


SPORT PKG[ZSP]

Original Price:$1300.00
Details:
Tires - Rear Performance
Tires - Front Performance
Bucket Seats
Aluminum Wheels





6-SPEED STEPTRONIC AUTOMATIC TRANSMISSION[205]

Original Price:$1275.00
Details:
6-Speed A/T
A/T
Auto Transmission w/Manual Override


PADDLE SHIFTERS


2007 BMW 3 Series 335i*Navi Standard Equipment

[rf900rkw]

All E39 automatics have a top ratio that is overdriven, but only one unit has a physical overdrive. If you tell us which of the eight different automatics used in the E39 you are interested in, I can provide the exact ratios.

[BavarianE31]

Thanks, but all the info I have about the car's transmission is this:

5-speed automatic transmission w/OD-inc: sport mode, StepTronic clutchless manual shift control

Don't know if this helps but the 530i in question is 2002, has sport, premium and cold weather packages. Thanks

[rf900rkw]

Zf5HP19

3.67
2.00
1.41
1.00
0.74


Reverse = 4.10

[BavarianE31]

Thanks randy! I'm wondering what the other ratios are for the other transmissions? And what do you mean by "physical" overdrive? I thought as long as the ratios were <1 it was considered a OD gear. And I'm assuming the 5 speed manual is 1:1 with no OD?

[rf900rkw]

I can look up the ratios of each transmission, at least the US model ones, but it is of little value. The only thing the transmission ratio will tell you is how fast the driveshaft spins.

"Overdrive" is a noun. It is a thing, a physical device that alters the gear ratio. Many of my old British iron had a 4speed + overdrive transmission. This means it had a standard 4 speed manual, then a separate overdrive unit (Laycock de Normanville), giving 6 speeds as shipped, but I would modify the control switches to give all 8. Many cars throughout time had overdrives standard or optional; and there was a brisk market for add on devices. Ramblers to Jaguars.

Now, in the 1970's everyone had a 3 speed automatic utilizing a Simpson gear train. The Simpson gear train had a top ratio of 1:1, achieved by engaging the reverse and forward inputs at the same time, locking the entire thing as one rotating lump. Then the fuel mileage wars started, and having a taller cruise gear was considered a "good thing". Thus *everyone* grafted an overdrive section onto their three speed box.

C3 -> A4LD
200 -> 200-4R
C6 -> E4OD
400 -> 4L80
180 -> 4L30
And on and on. Everyone got in the game, included Nissan and Toyota. Even ZF. Every one of these transmissions was a three speed and then an overdrive, giving the potential for six forward gears and sometimes two reverse. No one used it as such, though. Just 4 forwards.... until in the 1990s Ford started splitting and did 5 forward gears.

But these boxes were inefficient in both energy and space used. So the next generation transmissions moved on to different gear train setups that by design gave four forward gears and one reverse. These transmissions were very close to the same size as the old three speeds (think 700 vs 350, AOD vs C4), produced ratios similar to what the overdrive units were doing, but didn't contain an overdrive.

But it was too late. The professional lying bastards (marketing) had toughted the overdrive so much, they couldn't let go. So these new four speeds got the overdrive label, even though they weren't. And the misconceptions and marketing BS snowballed from there.

As an example of that, Ford took their standard four speed transmission, made the 3rd gear ratio less than 1:1, then grafting in a really rediculous and fragile linkage so that the pattern went 1-2-4-3. Marketing. They should be first on the spaceship sent to the new world....


The big lie in all this is that using an overdriven top ratio is not the most fuel efficient way to do things. BMW and ZF did it right with the manual. As I said at the top, all the overdriven top does is make the driveshaft spin faster. What matters is the overall gear ratio, trans times diff. Which sounds more reasonable, passing straight through the transmission with no ratio change and then gearing down 3:1 at the diff, or gearing up 25% in the transmission and then gearing down 4:1 at the diff? Obviosuly the one with the least change will be more efficient, but Marketing wo't get their "overdrive" buzzword. Did I mention that marketing should the first ones on the one-way space shiop, along with the phone sanitizers?

[BavarianE31]

Oh, I see. Very informative post! You must be a transmission engineer or something. Curious to know which on has the true OD. Is there a source for the rear diff ratio for all the models? I'm just interested in the 2002 530i, but just for poops and giggles.

[rf900rkw]

The 4L30 used in most E36, Z3, and 528's up to 99 started life as a three speed in Opels and Chevettes and such. It grew an overdrive section (the front pan area) and rudimentary electric controls around 1990.

For the final drive ratios, probably the easiest is to use realoem.com. If you have the VIN of your subject, you can get a build sheet from www.rubmw.ru/vincode/eng/ (http://forums.bimmerforums.com/forum/www.rubmw.ru/vincode/eng/)