W113 Pagoda SL Group > General Discussion

4 Speed Gearbox Bearings--for Benz Dr

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George Des:
Dan,

I just disassembled a 4 speed manual box. Everything inside looks good--the gears aren't missing any teeth, no chips or scores, same with the synchro rings. The bearings, however, looked fairly bad, especially the upper two on the mainshaft and the input shaft. Looks like they rusted somehow. The two uppers are SKF 6306 C3 with snap rings. The rear one is open and the front one is shielded on the inner side only. On the countershaft it looks like two FAG 6305 ETN/C3. These appear to have phenolic bearing carriages instead of metal with the closed side facing to the inside of the box. Can you tell me if these are the stock bearings for this box and if so what is the downside of using a std i.e. open or single shielded SKF or equivalent bearing on the countershaft ?

George Des

hauser:
George, I'm sorry I don't have an answer for you but I do have a question.  Are parts for the 4 speed box available and if so are they easy to find?

1969 280sl 5 spd        1999 ML320          Gainesville,Fl.

Benz Dr.:
These are standard bearings although you may have to order the ones with the locating rings. I usually remove the plastic covers if they have them. The trans fluid will lubricate them properly.
The smaller needle bearing ones on the shafts are normally OK and don't need to be changed. Setting the end play on the shafts is very important or it won't shift well. The input shaft can't have any end play at all - most do and that's not good.

Daniel G Caron

Ben:
I overhauled my 4 speed and bought all the bearings locally, all were ex-stock except the ones with the locating rings which took a few days, no big deal.

As Dan says the endplay is the major thing to watch out for.

Dan, do you set the endplay at the front end

Regards,
Ben in Ireland.
'64 230SL 4sp.
'03 CLK Kompressor

Benz Dr.:
The front and rear covers have wafer thin shims that set the end play. Most of the time you can just put everything back in and you're OK.
The input shaft is a different deal on most of them. I'm not sure but it seems like they're often apart before and people loose parts or don't bother to mark things coming apart. Most of the input shafts need about a .020'' shim to remove the end play. If you can wiggle the shaft around it's too loose. Set properly it won't move at all or very little. Somehow this affects the shifting as everything inside the box will move the .020'' if it's not tight. Even that little bit taken out will make the trans feel crisp while shifting.

There are some parts available for the trans but the gears rarely break or chip. Using gear lube will harden the gear faces and may cause them to chip - it won't work all that well on the brass syncros either.
 Trans fluid has some unique properties which allow parts to lock up solid one second and then spin freely the next. Think of how an automatic trans works.

Daniel G Caron

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