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Mercedes-Benz Transmission Transplants
By John | January 14, 2008
Question from subscriber ….
Hello John. I wanted to pick your brain on a transmission question. I have a '71 280SL. According to some rumors floating around, a manual from an '86 300E, would fit the 113. Supposedly, the 300E manual is a smooth 5 speed. Do you know if this would be a fit and if so, would it simply be a plug-n-play arrangement ?? I would love to convert my auto to a really nice manual. Thanks. Attila.
Reply by Olson ….
No, a 1980s transmission is not a "natural" implant. Bell housing would require significant change, length of trans. is different — requiring custom spacers, and worst, it is a "side shifter" — the control levers do not come out of the top of the box as on the 113 manual transmissions…. this means more improvisation and odd location for the lever coming out of the tunnel.
The correct 5 speed manual transmission for your "Pagoda SL" (and most other 1960s Mercedes-Benz) is a "top shifter". The smartest way to acquire one is actually buying a 230SL with a 5 speed box (the most plentiful source), swap all the parts and sell the donor car. That is because buying a transmission is only the beginning. Drive shaft is different. If you're changing from an automatic the fly wheel and ring gear is different. Also you can know it shifts OK and is quiet before you buy it if you can drive the car. BUT… see next paragraph.
The whole project is unnecessary as changing the rear axle/differential (rear-end gearing) is infinitely easier. I now favor changing rare axle ratios to finding a five speed, for 1960s Mercedes-Benz. 280SEL 3.5 or 4.5 sedan parts offers soe nice ratios. Identical measurements. Everything fits. Your 280SL probably has a 4:08:1 rear ratio. That's OK if you live on Pikes Peak. For anything else there are three sedan rear ends (good: 3.69:1, better: 3:46:1, and best: 3.27:1) that will move fourth gear into overdrive with quieter highway cruising. There's only minor reduction in low speed performance. First gear is already so low that it can accept a longer legged (lower numerically) rear end ratio. I did this with my 300SE (six cylinder) sedan; installed a 3.27:1 differential from a 280SEL 4.5… and I love it. MGP climbed 15% too.
280SEL 4.5 sedan differentials with either 2.24 or 2.27:1 ratios are lurking in many Mercedes recycling yards. You'll want to replace the axle bearings on principle, but for a small fraction of the cost of a new differential, you'll probably be as happy with the results as I am.
Topics: Mercedes-Benz Modifications, SL Market News |
One Response to “Mercedes-Benz Transmission Transplants”
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January 15th, 2008 at 12:16 pm
This makes great sense and makes me really think about swapping out the rear end of my 71 350SL euro (yes, a 107 chassis). It is a 4-speed manual, and I believe it has a 3.46:1 rear end, which makes for some high rpm highway cruising and very, very short 1st gear. Am I correct that a US-spec 450SL has 3.06:1 rear end gearing? I wonder if this would yield similar results to your example above? Would I want to go even lower (numerically)?