6 Speed conversion using Anna Thom Engineering Transmission

[Fred Verboon]

Thanks Garry, may I ask you what happened with your Getrag?

Kind regards, Fred

[Fred Verboon]

Dear Michael,

Thanks for the advice! 

Kind regards, Fred

[Benz Dr.]

Before I even considered going to a higher gear ratio in final drive, I did a bit of research.
 A typical 4.5 sedan has about 230 - 240 HP and weighs about 3,800 lbs.
 A 280SL weighs about 3,000 lbs and has about 175 HP.
The 4.5 sedan has a power to weight ratio of about 16 lbs per HP.
The 280SL has a power to weight ratio of about  17 lbs per HP.
Of course, torque plays a major factor here and that's where the 280SL rises above the rest for axle ratio changes.

Ideally, a final drive ratio of 3.46 is just about perfect for our cars as it gives you lower engine RPM's but is still in the torque band of the engine. Driving at speed, outside of the engine's designed torque band is probably not a good idea. Modern cars are designed to work that way but ours need RPM to perform properly. You can tweak the parameters of the original design but at some point, you will have modified the car so much that all of the original character is lost. Why own one if you don't like it in stock trim?


I actually did the  3.27 conversion in a 280SL probably 25 - 30 years ago and while it worked OK it was in auto and the transmission really groaned until the car started to move.  From that early experience, I knew that a four-speed would handle the higher gearing OK but not an auto transmission. This has been my only recommendation ever since. If you do a lot of high-speed long-distance driving on expressways, this could be OK for you. Live in the mountains where you rarely go that fast and need torque to climb steep hills? Maybe not so much. 

[Garry]

Fred,


After fitting the Getrag to my 280 that was data carded for five speed but missing that gearbox, and using the Mark Bull conversion kit, ZF then announced that they were producing 250 new 5 speed gearboxes suitable for our cars at €7800 and i was able to get one of these new ones. I hate to think what the price is now if you can find one.


 I put it aside in its box and when i sold that vehicle some time later i also sold the gear box with it to the new owner who i believe had it fitted.  I don’t know what happened to the removed Getrag gearbox but do know the car with zf 5 speed gearbox fitted ended up in Sydney.


Garry

[mdsalemi]

...but ours need RPM to perform properly...

...and yet, Dan, the constant chatter to reduce RPMs!

My car does lovely and feels best on the highway at a rip-roaring 4000 RPM. Cannot hear a bloody thing, and I often wear earplugs (no kidding; I keep them in the car). It is what it is.

If I want supreme luxurious highway comfort, I'll take my daily driver...at the same 78MPH its lolly-gagging at a leisurely 2200 RPM. Different engine, different car, and different times...

[Fred Verboon]

Hi all.

I have been looking on the internet and unless I am wrong, the same picture keeps appearing when looking for a 6 speed gearbox.

One for 7000 USD: http://www.2040-parts.com/new-6-speed-manual-transmission-gearbox-for-mercedes-230sl-250sl-280sl-pagoda-i1646448/
This one for 7500 EUR: https://oldtimer-ersatzteile24.de/6-speed-gearbox-for-Mercedes-230SL-W113-Pagode
And even on SLShop the same paicture appears: https://www.theslshop.com/parts-shop/mercedes-benz-w113-sl-w111-4-5-speed-to-six-speed-manual-gearbox.html for 7850 Pnds.

According to SLS it is an Getrag. But they are currently named Magna PT.

Does anybody have any experience or even know what brand this gearbox is?

[Fred Verboon]

Thanks Garry for your answer. Sorry for my late reply.

[Fred Verboon]

Dear all,

My Pagode has been fitted with the 6 speed Anno Thom (Getrag) gearbox. This is to let you know my experiences.

I drive a silver 230SL. The car was restored in 1995 and later equipped with a 280 M130 engine. The body of the car has been restored to high standards and still looks great. The technical bits were not done right. The car was driven for a few years and then stored in a very dry garage and was driven a few miles on average each year.

When I bought the car, I was not really impressed with the way it drove. Very high revs on the highway and irregular idle revs.
We decided to technically restore the car to its original but also make improvements to make it a real drivers' car. Van Dijk (ClassicSL) did a great job and replaced almost all technical parts, varying from everything made of rubber to a full rebuild of the back axle. So, now the car performed great. However, the highway revs still annoyed me.

Together with Van Dijk, we decided to replace the gearbox (that worked fine) with a 6 Speed Getrag gearbox, AKA Anna Thom.
The gearbox is a Gertrag Inline 6 speed gearbox that was adjusted to fit a 280SL/M130. When Van Dijk fitted the gearbox, we found out that the gearbox did not fit the tunnel, which needed some adjustments. The rear drive shaft also needed to be replaced, so the installation was not as effortless as we hoped for. However, the result is phenomenal. The gearbox als clutch feel like new (which they are) and the car handles great. The gearbox shifts very short and accurate, the clutch is like a new car and it totally transforms the car.

In the end, we spent more than 20K EUR on the technical restorations and an additional 10K EUR on the gearbox and necessary adjustments. As a result, the car drives great. Much better than the 5 speed Getrag that I drove..




 






 
 

[Cees Klumper]

Thanks for the update Fred, that is good to know.

(On my US spec automatic, with a 4.08 rear differential, I had it replaced with a 3.69 to address the high revs on the highway. It also made a big positive difference.)

[Benz Dr.]

...and yet, Dan, the constant chatter to reduce RPMs!

My car does lovely and feels best on the highway at a rip-roaring 4000 RPM. Cannot hear a bloody thing, and I often wear earplugs (no kidding; I keep them in the car). It is what it is.

If I want supreme luxurious highway comfort, I'll take my daily driver...at the same 78MPH its lolly-gagging at a leisurely 2200 RPM. Different engine, different car, and different times...

You've made my point without my having to even make it. 

[SEB]

Hi Fred! Thank you very much for sharing your experience. Do you know the type of the 6 Speed Getrag what is used by Anna Thom?