Transmission Lube, down shift problems

[platt-deutsch]

I put over 100 miles on my 25 this weekend. It has 600W in the transmission. I just thought I would try the downshift to 2nd from 3rd. I tryed it at 25 mph.. I double clutched it as I always do.. Had to rev the engine pretty good but shifter smooth as butter.. 20 mph worked better and 15 was no effort at all.. Just a quick tap on the accelerator to rev the engine.. no problems..

[MikeC5]

Thanks PD. That's a good data point I can test against.

[MikeC5]

I finally got out there and tested it with the STP in the gear box. The upshifts seem a bit smoother but I still can't downshift unless going very slow (speedo isnt working properly). What do you guys do when coming to a stop? Do you just wait until its going too slow for third and then shift to neutral?

[R.White]

Not wishing to labour the point, Mike but I still think you should be using 600w. STP could well help but it is essentially an additive rather than an alternative. Molyslip G is great stuff but modern lubes such as HP gear oil are known to attack brass bearings sometimes found in older transmissions and diffs. Penrite supply appropriate lubes for our type of transmissions (but I can get it cheaper; sold as steam cylinder oil).

Ray.

[1930]

Gotta use 600 W and even then your pushing your luck, cant quote it but I have read original manuals say use the heavy weight and then add grease to it on top of it? Sumpthin like that

[R.White]

In the old days they did mix oil and grease but a good oil modern oil additive is a better mix these days. STP or Molyslip will enhance the oil where grease will break it down after a while.

[MikeC5]

I'll have to give it a try (steam cylinder oil) but I have a strong suspicion that I will need practice, practice, practice more than anything else.

[fozz71]

Can anyone explain the time involved, in using a GL-5 gear oil, that damage will occur? I haven't seen any definitive evidence as to how rapid or slow the sulphur damage takes? The tolerances on these older trannys are big compared to modern high pressure units. So, if I use 90W or 140W in my gearbox- and I drive 50-100 miles in a year, how soon will it eat away my brass and bronze? Just curious.

Thanks,
Jim

[fsnooks]

I used 600W gear oil.

If you still have problems get some 1500W and mix some. 2/3s 600 and 1/3 1500.

[MikeC5]

I think I'll try that when I gt her back on the road in a few weeks...