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Transmission and Rear End Oil Viscosities (sp?)

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Good day all!! I would like to explore the possibility of doing a fluid exchange in the Transmission and Rear End due to what I am perceving to be an overly laborious shifting procedure in my 1928 GE Dictator (242 CI). When the car is cold, it seems that my shift from 1st gear to 2nd neees to be done almost like a speed shift, and the shift from 2nd gear to third gear I need to double clutch, making sure the engone speed drops almost to neutral, all to try to avoid grinding gears. After the car has driven a while, and is warmed up, it seems that the wait time in between gears with the clutch in, is forever.

I took the car to Sagamore Hill on Long Island yesterday, which is the Theodore Roosevelt estate in Oyster Bay LI. The car made it using the above, and a little bit of gear grinding. When I went up a somewhat steep and lengthy hill going up to the estate, I had to down shift three times, because I would come down to second, let the car speed up and really wind out, and then shift into 3rd at a point when the car is just about too slow for 3rd, at which time, I would have to re-downshift to 2nd and try again.

I have seen people say use 90W oil, which makes sense. I have seen others say use 600W oil for Model As, which seems to me to be way too thick, and even Snyders Auto Parts says it's grease like. I know if my car uses 30W engine oil and I even put 90W in it, I will kill it. I don;t wnat to do that to my transmission.

Does anyone have any ideas?

Thank you as always,

Keith Gramlich

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On my 27 comm. roadster big 6 I too was having trouble shifting and upon the advice of a couple of car guys I switched to 30 wt in the trans. I am not an expert on this subject ,Howeverit didn't take me long to figure out that this was not the way to go.

somewhere in turning wheels or the antique

studebaker Review it was suggest to use: NAPA mineral gear oil SAE 90 api gl 1. Instant improvement! Also, remember these old cars shifted out of first gear at only a few mph. To second let engine idle way down and same for third. Mine dosen't shift perfectly but better than before. This worked for me.but no guarantee it will for you. Good luck . Commander Dave

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I know better than to get into oil discussions but what the heck.....

If you don't have any yellow metal (copper, brass, bronze) in your transmission or axle, GL-4 lubricant is a much better lubricant than GL-1 for spiral bevel gears, spur gears, helical gears, bearings, etc. due to the anti-wear additives. It is not used for hypoid gears. GL-4 will corrode yellow metals though, so if you have any yellow metal bushings or brass synchronizers in the transmission you'll want to stick with GL-1. My Light Six rear axle has no yellow metals so GL-4 is the way to go. The transmission on the other hand has brass bushings for the gear to shaft interfaces so I'll stick with a GL-1 lubricant for it. As far a viscosity goes, I would recommend 90wt for both axle and trans.

With a non-synchronized transmission it is best to double clutch to speed match the gears to avoid clash. It comes down to technique....vehicle speed vs gear vs engine speed vs timing. When you change oil viscosity it changes how quickly the input gear and counter shaft slows down. This will usually require a change in your timing technique.


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