Did Mercedes manufacture the complete 928 automatic transmissions?
 

OK, so the question title seems dumb at first, as it is well known that the A22 and A28 automatics were essentially the same internal design as the Mercedes 722.3 and 722.4 automatics.

What I'm curious about is where the Mercedes bit of the manufacturing leaves off. Did they supply the internals to Porsche, who manufactured the cases, or did Mercedes make the transmissions complete with case and Porsche just bolted them in.....or did Getrag somehow get into the mix?

Thanks y'all,
-Mirror

All parts which have MB part number were obviously same as in Mercedes gearboxes including actual gearbox case. This means practically everything between torque converter housing and differential are mercedes parts. Only part numbers starting with 922 (A22 3sp), 960 (A28 4sp) and obviously 928 are Porsche specific. There aren't many in area between converter and diff and those that are are mainly external selector parts. It would make sense that actual gearbox were made in same production line as Mercedes boxes and they were pulled off it for Porsche external parts at end of the line. Perhaps only once they were totally finished and some parts need to be removed even.

It would make sense that at least differentials were put in at same place where manual gearbox differentials were done, wherever that was, Porsche, Getrag or elsewhere. Same measurements need to be done in both types of gearboxes and it would be stupid to do such a specialized job in many different places.

Both of those would make sense but at the time Porsche did many things hard way.

My car's gear box has Porsche designation of A2816 3L 02446 stamped on the intermediate case.

In the Porsche Manual for Automatic Transmission A28 states on page 3 "The digitis stamped on the right side of the transmission case above the ATF sump are for production control only".

In actual fact these numerals are the Mercedes Benz series number and the transmission number.

For example, the 722 400 02 147104 has the following meaning:
a. 722 designates Automatic Transmission
b. The digit 4 designated the Model of Transmission. My car has a 722.3 series type transmission and the 3 designates that it is a 4 speed/6 bolt pan/Large Case
The numeral 4 above would designate that it is a 4 speed/6 bolt pan/Small Case.
c. The follow "00" designates the type of automobile or Version Number and is used to determine what modulator and the adjusted pressure required
d. The last six digits is the MB serial number

From the above I would suggest that the auto transmission was manufactured by MB, as a standard MB box with the ends designed to fit to the Torque Tube and the Transaxle.

This can be verified if you view PET and you can see the actual Porsche Part Numbers prefaced by 928 and the transition into the 960, 722 and 126 etc.

Not sure of the part numbers prefaced by 960, however, the 722 numbers and the 126 numbers are MB numbers, as far as I can determine.

Tails 1990 928S4 Auto

That is Porsches way of saying those number will not tell for what 928 gearbox was made for and only correct number is Porsches own style of numbering like A28/16... In reality MB numbers can be used to say to which 928 gearbox will fit.

960 is Porsche specific part for 4sp automatic same way as 922 is Porsche specific part for 3sp automatic. These are only parts which were specifically designed for mounting automatic gearbox into 928.

928, 911 etc part numbers are more generic model specific parts which were used in 5sp 928 and other Porsche models also.

123, 126 and 722 are all Mercedes parts which were used in some period MB models. They can be found from any MB parts supplier using same part number. AFAIK none of them are Porsche specific and this means 928 use exact same stuff as S-class MB for example.

900 and 999 are generic parts which are not designed specifically by or for Porsche. They are for example bearings which can be found from bearing manufacturer catalogs etc.

I can't answer with any authority but,I just removed the auto trans from my wifes 85S and the donor 85S w/lsd and they both have a Mercedes emblem cast into the top of the trans case.

Awesome info guys, thanks a bunch! Geez you people are a goldmine of information.

All in all, sounds like its safe to say that the automatics (casings included) were indeed wholly manufactured by Mercedes Benz.....aside from perhaps some 928 specific mounting parts.

Cheers,
-Mirror

According to the shop where I got some spare parts for the transmission in my S4, it was made by ZF.

Edit
The shop could get spare parts for my transmission, but they were a lot cheaper at the local Mercedes workshop so I bought them there.

/Peter

The front torque convertor cover allows the Mercedes transmission to be moved back from the engine to the rear and attach to the torque tube . The differential housing with the Porsche ring and pinion bolts to the back end of the specially modified automatic transmission case in place of the usual output shaft used on the Merc. Basically the same thing as was done on the 924 , 944 put the trans in the rear and hook it together with a LONG driveshaft torque tube just as GM had done in the early 1960s Pontiac Tempest ..... The 924 used a front wheel drive transaxle (Audi) simply moved to the rear. Pretty much answers the question about why there is no transmission fluid dip stick on the auto transmission to check fluid level on a 928 ......the transmission was supposed to be mounted to the engine !

OK just so I can be a complete pain in the ass, would Mercedes-Benz be the correct company designation to use for the automatic transmission manufacturer, or would Daimler-Benz be more correct? Looking through Ludvigsen's volumes on Porsche has him using Daimler-Benz.

On second thought, nevermind. Daimler-Benz may technically be more correct, but I have to stop this silliness somewhere. I'm gonna go list Mercedes-Benz in my specs database.
Thanks y'all.

-Mirror

Mercedes is a brand name of Daimler AG ...... much as Pontiac is a BRAND name for GM .....Jaguar for Tata ....

Jaguar for Tata - that is so sad 8>(

Exactly...and that's where it gets confusing. For example, Pontiac is a brand name for GM, as you mention, but in the old days Pontiac-specific engineering teams did their own engine designs (or derivations off of general GM engine architecture)...so does that make them GM engines or Pontiac engines? Nebulous.

So in Mercedes-Benz case, they were a subsidiary of Daimler-Benz back when these transmissions were manufactured. Mercedes-Benz is technically listed as a manufacturer of automobiles in the German business registry as far as I know, so that's where it gets nebulous again.

Daimler-Benz is probably technically correct to be listed as manufacturer, but I'll go with Mercedes-Benz for the sake of familiarity.

Whew!

And of course it was Daimler-Chrysler not too long ago.

BTW - the proper pronunciation of "Daimler-Chrysler" was "Daimler" - the "Chrysler" was silent...

To go even further off - and speaking of Daimler and Jaguars - what was with those "Daimlers" that looked like Jaguars when I was in Europe as a student back in the '80s?

lifted from WIKI.... "The ill-defined relationship between the inventors and DMG harmed the image of DMG's technical department. This continued until during 1894 when the British industrialist Frederick Simms made it a condition of his 350,000 mark purchase of a Phoenix engine license, which would stabilize the company finances, that Daimler, now aged sixty, should return to DMG. Gottlieb Daimler received 200,000 gold marks in shares, plus a 100,000 bonus. Simms received the right to use the name Daimler as his brand name for the engines. In 1895, the year DMG assembled its 1000th engine, Maybach also returned as chief engineer, receiving 30,000 in shares.

During this period, their agreed to licenses to build Daimler engines around the world, which included:

France, from 1890, by Panhard et Levassor and Peugeot
USA, from 1891, by German piano maker Steinway
United Kingdom, from 1896, by Frederick Simms as his Daimler Motor Company
Austria, by Austro Daimler
Daimler died in 1900, and in 1907 Maybach resigned from DMG.." ......"

So under license Simms owned the famous Daimler name in the UK as the Daimler Motor Company made a small Hemi head V-8 engine in the 1960s put them in a weird fiberglass roadster and transplanted them into Jaguar bodies....Daimler Maybach and Otto along with Benz were the inventors who created the automobile !