G76/27-5 vs ZF manual 5 gearboxes

[GGR]

Hi all,

I saw on EPC that the W108 280 SE 3.5 was coming with a choice of two 5 manual gearboxes: one is the G76/27-5 and the other one is a ZF one. Unfortunately the latter is not detailed at all on EPC. Strangely, the ZF gearbox didn’t seem to be available on 3.5 Coupes or on later 350 SEs or SL/Cs. I have some questions:

· Can the ZF gearbox be separated from the clutch housing?
· If yes, can the ZF gearbox be mated with the same M116 clutch housing used by the G76/27-5?
· Is the ZF gearbox housing alloy or iron? (ie lighter than the other one?)
· The G76/27 gearbox doesn’t have a very good reputation. Is the ZF better? Stronger? Can it hold more torque?

Thanks in advance

[deanyel]

Why do you say the G76/27 doesn't have a good reputation? I would have said it was the other way around, that the ZFs didn't have a good reputation, sloppy, notchy. I've had a couple of G76/27s and they were both magnificent.

[sjefke]

The 3.5 V8 engines had the G76/27-A version of the gearbox. The "A" version is different from regular version in that it has different ratios and stronger shaft and bearings. They are both in the EPC (somewhere) and also in the workshop manual for the 3.5 cars. I know because I checked the differences in part numbers on point in time. Workshop manual describes the differences. Also different actuation rod in bell housing as well as different master and slave cylinders than 6 cylinder cars.

As far as I know, the G76/27-A 5 speed was listed in the manual, but never fitted in an actual car. If you see a G76 5 speed, it is the 6 cylinder transmission. Same with the ZF. Always fitted in 6 cylinder cars. The ZF is very "exotic" in that Maserati also used it, which makes it VERY pricey to buy used. I think Bentley also used the same transmission. (I think I saw one last year on Ebay for $1500-$2000 used, sold as is)

I would not fit a G76/27 to your 3.5 coupe (or sedan) if it is not the A version, but if you want to, you will need for sure:
- the V8 manual transmission bell housing from a G76/27-A (tought to find loose),
- flywheel (impossible to find),
- clutch plate ($200+ new),
- pressure plate ($200+ new),
- release bearing ($55),
- the 3 piece drive shaft (impossible to find) or custom lengthen other driveshaft,
- pedal assembly (tought to find),
- master + slave cylinder (about $100+ new each but one of them just became NLA). Again, master and slave are DIFFERENT for V8 and 6 cylinder.

And make sure that whatever transmission you buy has all linkages included. They are can be VERY hard to find and expensive.

You are better off getting a manual 4 speed G76/27-A with ancillaries from an old sedan in a junkyard and putting a 3.27 rear diff in your car than trying to mate it with the 6 cylinder 5 speed. Either way, it is a major parts search operation. There is a good thread somewhere if somebody trying to put a 5 speed in his 250C only to give up because the linkages were impossible to find.

Good luck,

Bert

[GGR]

Thanks Bert,

My car is a '62 W111 Coupe in which the previous owner fitted all the running gear of a 3.5 Coupe, including rear axle.

Indeed, a manual 4 speed G76/27-A with a 3.27 rear diff is a good option.

Would you know if the 350 SLs fitted with a 4 manual would be a good donor car? I guess the gearbox is the right one, but what about the ancillaries such as drive shaft, pedal assembly and master + slave cylinders?

[sjefke]

I bet slave and master will be the same (but I would check first). Pedals itself may be the same, but I have my suspicions that they are not. For one, there is a rod connecting the clutch pedal to the master cylinder that probably will be different. There is a whole section on how to adjust that properly in the manual meaning it is dimensionally very precise and I expect it to be different. Check the part numbers in EPC and see whether they are the same or not. Drive shaft will probably be different . After all, 350SL is shorter than W111 (at least I think so). But driveshafts can be modified.

Bert

[deanyel]

Indeed, both mine were 3.5 coupes and A versions. And I've never seen a 27A-5. I think if it was ever made it would have been a later 107 350SL.

[todds]

ZF 5psd's are nothing to write home about, I've never been impressed by the ones in the Alfas I've owned, unless extremely cranky second gear syncros and difficulty getting into first are things you enjoy. It felt like waiting to shift cleanly in those cars took more time than actually accellerating up to that point. The gears are super heavy duty and therefore the weak syncros have a hell of a time getting them to move. A few people have been very successful in lightening the gears in those boxes though, it is supposed to transform them.

[GGR]

all this pleads in favour of the G76/27-A.

Bert: did you equip your car with a 3:27 end ratio, and if yes what is the result?

[Arthur Dalton]

B/C the 5 speed is an OD trans, the 3:27 w/4 speed upgrade is close to the 5 speed w/stock diff in top gear. The math comes out close, but the gearing will suffer on the low gears w/3:27... [ but not much, and some actually prefer it b/c of the close gearing of 1/2 ]
I see the 3:27 also done w/auto trans , but not my recommendation.

[Tony H]

I installed a 3.27 axle in my 3.5 coupe. It makes the car MUCH more drivable. The 3.69 is so low that 1st is practically unusable. As soon as the car is moving it's time to shift into second. I live in the mountains and have had no trouble. it's been 5 years since my car has been on the road but the difference is still fresh in my mind. I have had my trans and driveshaft rebuilt as part of my restoration but the car is still dissasembled.

[Arthur Dalton]

I can remember doing the 3:27 conversions years ago and getting crap from eveyone for doing the change .
Now it's the "Thing " to do...so much so that they are getting hard to find...we used to be able to pick them up for peanuts.......

[sjefke]

I am still on 3.69 and don't mind it that much. I do mostly city driving and I agree that first gear is just to get you going and almost ignorable. Interestingly, one of my colleagues has a 2000 SLK and he had the same observation about his 1st gear. Must be a German mountain gear.

Finding a 3.27 has not been high on my priority list yet, but given Arthur's observation I may start looking for one. They may be getting rarer, but then again, plenty of W108 4.5 cars that get scrapped.

Bert

[Arthur Dalton]

A 3:69 is actually not a bad match and there is not a big difference to a 3:27. I don't recommend that change if the guy is doing around town driving either.
The guys that notice the big change are ones that go from a 3:92 or the 4:08 to the 3:27. Another thing is these cars orig. came with Euro sized tires , which were 80% aspect ratio sidewall, so they were a tall tire...when guys go and replace them with a shorter aspect sidewall, [ 70 , or even 65's ] tire, they compound the ratio factor.

As far a 108 4.5 in the scrapyards, that was yeaterday...not anymore.

And when you do find one , they are now hip to what to charge you for one.

[Tony H]

I was once chastized on another MB forum for installing the 3.27 on my car. I can see their point but I want to actually drive my car. I can always reinstall the original one. I don't think it would matter if I ever sold my car but I plan on having it forever.

[sjefke]

GGR:

I just checked Ebay and there is both a 350SL and a 350SLC for sale with manual transmissions. And forum member Al (alibasi) has a 350SL with manual G76/27-A transmission (but no engine) as a parts car.

Bert