Jonathan wrote:
My 2CV is currently on 255,000 miles, and even though the engine had new barrels and pistons in March of this year, the gearbox hasn't had any work done to it yet, so is starting to get a bit weak on second syncro. When I'm down on the British mainland it tends to crunch on the way up the gears, as I'm having to change gear quickly in order to keep up with all the traffic. It's absolutely fine and dandy up here on the very quiet roads of the Shetland Islands though, so I'm not too concerned at the moment. Hopefully get it rebuilt next Spring.
I'm not sure why mine does not grind or make any noise at all when going from 2nd to 3rd.
Or 4th gear syncro is a bit weak and that's not stopping the transmission from spinning when going back to 3rd. And why double clutching does nothing. Years ago I had a different Fiat 124 Spider with a worn 2nd syncro and to prevent it from grinding when going from 1st to 2nd I would double clutch it before going to 2nd. I can't remember if it grinded or not when going from 3rd to 2nd.
It's just when going from 4th to 3rd that it does it and not all that time at that. So I must be shifting at a specific RPM when it doesn't happen.
One thing I have noticed (and may just be a coincidence) is when the gear oil is cold, it doesn't seem to do it at all until I've put some miles on it and heated the oil up.
Like in the case of my Yugo, where 20W50 permitted easier shifting in cold weather caused grinding in 3rd gear when upshifting but going back to GL-1 90 cured (or masked) the problem, I wondered if using a heavier viscosity oil in my 2CV would help things.
Finding GL-4 in any weight is hard enough. Actually I think the 80/90 EP I used is thicker than what is recommended anyway. I believe the recommended weight is 75/80 which is not much different.
I still have enough of the Lucas oil additive to give it a try. You replace 25% of the gear oil with this stuff. But says in heavy duty applications you can add up to 50%. The MSDS says it does not contain sulfur additives. The bottle says it reduces heat which leads me to believe it simply thickens the oil. I do know the bearings in my Fiat Spider's gearbox and differential do not whine like it once did after using it.
With my Trabant, on the flip side, the freewheel device (or sprauge clutch) which kicks the drive train into neutral in 4th gear got to where it would not engage. In this case going from HLP 68 (or 30 weight) down to automatic transmission fluid (20 weight) would allow it to engage for awhile anyway. The manual says you can use SAE30 engine oil.
I tried flushing the gearbox with diesel and then it would engage every time. But using diesel fuel is not a very good lubricant.
I ended up having to have it fixed. But all the snycros in that transmission work fine!
That car is also front wheel drive but uses a mineral oil with zinc additives. It took allot of cross referencing but eventually determined HLP 68 is the German equivalent to American AW 68 which is used in tractors.
That's what baffles me. If my Yugo, 2CV and Trabant all have differentials built into the gearboxes then why does the 2CV require EP? What's so special about 2CV gearboxes?
Where I work we have various synthetic gear oils used in our pumps and equipment.
I think we have some oil that has a higher viscosity than EP 80/90 that might be compatible.
