RF overdrive 5th gear for Audi 016

Hi all.

I have now had the opportunity of doing some kilometers in my RF40 equipped with the RF overdrive 5th gear.

At an indicated 2100 RPM I am doing an indicated 100 Kilometers per hour. This appears to be significantly lower RPM for the same speed than I was getting before. The new gear does whine a bit, but overall I have found it a big improvement.

I know that RF are working on a new final drive ratio which offers better ratios for all gears. Maybe one day I will get to test test that, but this option is cheaper and certainly easier to fit. You can fit the new gear by removing the end case only.




Mike, apologies if it's already been asked, but what was the cost of the RF 5th gear and what specific component(s) were included?
Hi Mike Any chance of a picture, and any thoughs why it would make more noise.

Robert Logan

Defunct Manufactuer - Old RF Company

Love the look of the car and the location.

The reason for the "wine" is the overlap of the gears. We used a large overlap to spread the loading on the gears.

Regarding the R&P, I was quoted Aus$ 1980 per set if I ordered 10 sets. I passed on this at US$ 1800 (please check the exchange rate and therefore profit margins !!!!! ) and had only a few inquiries and NO repeat NO orders. I am not prepared to put $20,000 on the shelf to loose money waiting for orders.

My personal opinion was that they were very expensive and this is the reason I did not put any thing on it for me. The machine that is used to manufacture the R&P is the only one of its kind in the southern hemisphere and therefore the price.

Best wishes,


I will presume you know the basic process. Let me know if you don't. - there are 2 issues to watch.

1. There are large round circlip like springs in the syncroniser assemblies. These hold the 3 little plates called syncroniser keys out. There is one on each end of the syncro keys. Take note of where these are and where the little tag on the end of the spring is located. If you don't get these right they springs will work there way out and stop you selecting gears.

2. There is a small circlip on the mainshaft which holds the gear on to the mainshaft (the top one). This circlip controls the end float of the gear. If there is too much end lash the gearbox will fall out of fifth gear occasionally. End lash should be .05mm. It adjusted by getting a thicker or thinner circlip.

If you need any more info let me know.


Thanks for those words. I have been intending to send you a picture, but I am still trying to get a "good" one. The car is running really well.


Thanks John.


Believe I paid RF $ 520 US. I'm sure Robert can provide
you current price/availability. I'll post a photo next
day or two.



Hi All, Has anyone other than John ever got around to fitting one of these 5th gear options.
I would be interested to hear of any other reports. I am thinking that this option along with Mick’s 3.22 C & P (which arrived last week – thanks Mick, looks sweet) would be a great upgrade of my AAZ box.
Does anyone know what the ratio of this gear is. I think the original is 0.86.
Any feed back would be appreciated.
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Chris Kouba

Looks to be somewhere around .7:1 based counting the teeth on half the cog and doubling it. I get 19 teeth on the little one and 29 to 31 or so on the larger.

Should translate into roughly 20% RPM reduction. Maybe Mike DD could count the teeth for us if it's still out of the car(?).

Pete I not sure what your engine set up is. I found that with a heavy cam (stroker would be better) my motor doesn't like much below 2000 rpm in 5th gear, this makes the 3.22 C&P just about perfect for a good high rpm motor. My motor would be a pig as a daily driver if I increased the ratio. Obviously this depends on what the car is used for.


Mick, I was just checking the possible ratio’s in a speed calculator and I have to agree with you 100%. Unless we want to do 330 kph there would be little advantage other than very good fuel economy on the highway.
The Porsche 944 uses a fifth gear that is .7297:1 (27:37) p/n 016.311.353.E shifting gear 5th speed and p/n 016.311.159.R gear 5th speed. It's a popular conversion for the V8 944 guys for the turbo transaxles.