Tr. 508 J-254 A
Actual problems of life expectancy and the repair of the freewheel on the Synchronized transmission gearbox of passenger car type Trabant 601.
Although we pointed out our findings of the factory already within technical Information Service Tr. The 498, we see the need to point this out once again.The intention is to utilize the full life expectancy of this freewheel part and additionally to point out an economical repair strategy in the case of damage.
The analyze of the experience from VW and our r&d dept. lead to the following hints:
1. Life expectancy of the freewheel
It is going to be expected, that a Freewheel-cage made of carbon-nitrited steel as used since July 1972, will exceed the life expectancy of the freewheel mechanism significantly. Most likely, 60.000km or more will be reached, before symptom "Freewheel Slippage" will occur.
2. Check of wearout
The analyze of disassembled parts leads to the following conclusion:
Gearwheel of 4th wheel no significant signs of wearout
Rollers of the freewheel: No measurable wearout
Carbon-nitrated cage of the freewheel mechanism: No measurable wearout
Instead, the cam of the freewheel shows sign of measurable and visible wearout on the cam's surface. This are the conclusions:
The width of the wearout-mark on the freewheel cam's surface is no indicatior for the progress of wearout. These marks are already visible after a few kilometers!
The depth of the mark is a clear criteria for the progress of wearout of the freewheel, but precise measurements under workshop-conditions are difficult.
The repair shop has to assume, that 60.000 kilometers or more are possible without any slippage of freewheel.
Repair technology
3. Usage of new parts
According to 2., in case of repair due to "freewheel slippage" the following technology should be used:
- re usage of gear wheel of 4th gear
- re-usage of the 12 rollers of the freewheel
- re-usage of the carbon-nitrated cage of freewheel
- usage of a new cam
If there is an exceptional case where new rollers have to be used, please be careful that only rollers of one and the same size category are used. If you don't follow this instruction, the freewheel may fail much earlier than the expected 60.000km.