Hallo! This maybe my second post. My name is James Seabolt (Sebold) and I live in Eastern Tennessee USA. My Trabbi originally came from Hungary. I've owned it since September of 2012.
My current question concerns the freewheel device and gearbox lubricants.
I could not find this HLP 68 initially so I used SAE 30 engine oil. Which worked well even below freezing.
In the summer of 2013, my freewheel device started giving me trouble engaging. I've heard of people using automatic transmission fluid which has the same viscosity grade of SAE 20. So I used Dextron III ATF. Immediately it fixed the problem until this past October when it started to get cold outside. Eventually 4th gear would not engage at all.
I was about to replace it but based on some opinions decided to flush the gearbox with diesel fuel for about 10 KM. Immediately 4th gear started engaging again. After a couple of flushes, I finally got all the silver sludge out of the gearbox.
I tried Ford Mercon ATF but still had to drive the car for about 3 KM before 4th gear would engage.
I decided to try an experiment. I decided to overfill the gearbox just slightly with 1.5 liters of Ford Mercon ATF and 500 ml of diesel fuel. So far this seems to work well in cold weather (0 to 3 C).
I have a theory. I'm wondering if "flooding" the freewheel device with oil will improve it's operation. My theory is 1.5 liters just "baths" the gears and oil is eventually forced into the freewheel device after 3 KM or so? But by overfilling the gearbox just slightly will cause oil to already be within the freewheel device.
Or maybe by thinning the gearbox oil by 25% with diesel just made the lubricant thinner (example: viscosity grade of 30 or 40)?
I finally found this HLP 68 lube from a tractor parts store. It goes under the name AW ISO 68th in the USA but have not tried it. I will wait until this spring when the weather warms up.
No doubt the freewheel device is probably worn but is it "worn out"? My car has 83.000 KM but don't know the history of it.
Once 4th gear starts engaging, it engages smoothly the rest of the day. But does not like anything thicker than automatic transmission fluid in cold weather.
Anybody use different grades of gearbox oil between spring/summer and fall/winter to get around this problem?
Since I saw an improvement after flushing the gearbox with diesel could the freewheel device still be "gunked up"?
I was told not to give up on it until I made sure the inside of the gearbox was clean.
Anybody know a safe mileage (kilometers) when doing a diesel fuel flush? I've just been going up the road and back for about 10 KM.
Any options on gearbox lubricants appreciated!