Jun 15, 2012 update to the Mercedes-Benz 230 S project car

A cheap fix for our transmission

We were tired of our Heckflosse jumping out of second gear, but couldn't stomach the $3000 we were told it would cost to fix.
It turned out that this funky nut on the end of this shaft was the problem after all.
All we had to do was buy this special tool to tighten it. We gave it the full twist of 150 lb.-ft. and all our problems are solved.

Son of a gun! After we tightened the flange nut, our speedometer stopped bouncing around and our transmission stopped jumping out of gear.

Despite second and third place rallycross finishes in a competitive class with much newer cars, we decided we were just plain tired of our old Benz’s annoying problem of jumping out of gear. Heck, we might even be able to win if we could just run the course in second gear without having to hold the shift lever.
In search of some information and another transmission, we put a post on the PeachParts board asking if anyone knew exactly what other old Mercedes transmissions would fit this car. We had a line on a diesel parts car, but before we took the plunge, we wanted to make sure it was exactly the same transmission. Turns out it is not, but it could work in a pinch.
After a couple of days we got a private message from a guy named Arthur Dalton of BenzTech. He told us that if we tightened up the flange nut on the back of the transmission, that it might solve our problem. He also told us that a sure sign that this flange nut was loose was a wildly bouncing speedometer. We had a wildly bouncing speedometer. Could the fix be that easy and not the $3000 transmission we had been quoted?
We quickly put our old Benz on a lift and sure enough, a previous owner had not properly installed the retaining tabs and the flange nut was only hand-tight. That’s a far cry from the 150 ft.-lb. specified torque. We could rock the flange back and forth an eighth of an inch.
Our local Mercedes specialist, Silver Star, sold us the special tool needed to tighten it. We also bought a new flex joint (guibo) from them: Ours was worn out.
Son of a gun! After we tightened the flange nut, our speedometer stopped bouncing around and our transmission stopped jumping out of gear. The total cost was a couple of hours of work and about $80 for the new flex joint between the flange and the driveshaft.
The U-joints and the carrier bushing were good, so we put everything back together and are very pleased. Since we have fixed two of the biggest defects on the car in one repair, we feel the car is now worthy of a restoration. Read all about it in coming issues of Classic Motorsports.

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View comments on the CMS forums
RHCorley New Reader
6/15/12 2:45 p.m.

I love it when a cheap fix can solve a major issue; as long as it's not a 'band aid' fix that will come back to bite you at a later date.

Qroger New Reader
9/5/13 12:18 p.m.

My best fix was using some rubber cement to fix the air leaks in the hard rubber hose between the air flow sensor and the throttle body. Before, the car wouldn't idle, had no low end torque, and was nearly un drivable.

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