New 6-speed transmission for W113

[TheEngineer]

I have the original engine, auto transmission, and rear axle as delivered. However, Dan, you know that this screams--about 4,000 RPM at today's highway speeds. This bothers a lot of people and there's no end to solutions to something that is characteristic, (not a problem) including new/different rear axles; engine swaps, and new/different transmissions with varying overdrive gearing.

I installed a 3.27 rear axle years ago and I am very Happy Happy Happy! About 3100 rpm at 62 MPH and still plenty of power going up-hill! My car has an A/T.

[Jimbo1907]

Looking at the ratios for the six speed, it looks like first is too short, and second too long.

I think the ideal changeover setup in 113 manual cars is to fit a dog-leg Getrag box, with the 1:1 fifth, and then change the rear axle to a 3.27 or 3.46. But dog-leg Getrags are very hard to find, and expensive when you can track one down (and the only one I found had a cracked case and we sent it back) so I opted for a standard non-dog-leg box with the OD fifth, and we reinstalled the original rear axle with its 3.92 ring and pinion,or 4.08, whatever it is.

[PagodaMafia]

Hi all, i have been running Siegfrieds gearbox in my car (1968) euro-spec 280SL for around 1 month now and it has been wonderful. bolted straight in.. dont agree that 1st is too short and and 2nd is to long..anyway each to their own. The extra torque really improves the acceleration from standing etc and no heat loss. It powers up hills at in top gear just wonderful as i can now hear the engine instead of the gearbox whine. Fundamentally the gearbox like the one i purchase has the period correct bell housing etc so it looks pretty stock when the car in on the hoist   if you choose an older box there is no way you get the sort of power delivery and stock look that this kit provides. A beautiful piece of engineering.

[PIP1947]

Hi Pagoda Mafia. This is interesting. You appear to have converted your car from auto to manual transmission, in the course of installing the 6 speed gearbox. Was installation of a clutch pedal, master cylinder, etc a big deal and can you give me an idea of the cost of the approximate cost of the change over.
Regards
Pip 1947
Sydney

[PagodaMafia]

Hi Pip1947 sorry about the late reply been travelling for some months now back in Australia. If you wanted to check it out email me on damoalucas@gmail.com if like so you can take a look. The install cost was pretty small but the cost of gear box landed is around 9.5 k.. in includes the entire kit pedals etc etc. Alex , his son and father are the best in town from http://www.silverstarservice.com.au/silverstar_contactus.html. They installed it no fuss.

Let me know if you need more picks

[BRYANH815]

I too converted a 1956 Corvette with a 4.11 rear end 3 speed to a Tremec 5 speed. This made driving the car a pleasure.  The car used to run at 4000 rpm at 55-60 mph  upon conversion this was bumped up by 1/3. The data above does suggest that the 6 speed would be too much for the engine ..lugging . A 5 SPEED MANUAL or 5 Speed Auto would be better. Bryan Hepper Barrington Hills ill. 1970 280 SL 1965 Stingray

[Jimbo1907]

The Tremec is a terrific transmission; lots of available ratios, and very precise shifting with short throws, etc. I have a TKO600 in my Kirkham Cobra and I love it. Very cool that you have a 56 Vette- best looking car they ever built, IMHO.