Free play on cluster in transmission ?

jrapose

jrapose

Senior Member
Yesterday I went thru the transmission on the 1930 car that I am redoing for a friend...I replaced the bearings and sealed it up ...but the main shaft (lower large gear set) gear had some end play to it... I could move it about 012" against the case...I know the very early transmissions had shims but this one should not...it is a good used gear set...so I added a .010" shim at the front ...now I am a bit worried that I might have it too tight...I basicly can not feel any end play on the gear and it appears not to drag... roataes easily..I think the oil is taking up the .002" that should be there if my measurement was correct... IDEAS ??? anyone think it is too tight for expansion ? it feels fine now, but how much end play in that lower gear should there be ??

Thanks....it is easy to fix now but once in the car I will kick myself if I guessed wrong...

Thanks Again....

Joel Rapose
Chester Ca. Where we just stopped the fire 2 miles from my front door.
Scared...You Bet !
 
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I would worry about heat expansion between the case and shaft and it tightening up. i leave approx .10 end play never had a problem as I feel this is normal.
 
Woa ! Maybe I better take that shim out... the free play was .012" and I put a .010" shim in....so .002" is too tight ? Sure glad I did not install it yet...

Thanks Joel
 
If I recall, Jim Schild's book had a copy of a Ford print that allowed a max of .020" for end play. The pic of the print isn't crisp but check it out first.
 
I am not worried about the max amount of free play....just the minimum...I will check it again today....I put everything together with a good covering of 600w oil...now that it has settled some hopefully I can get a .003" or .004" clearance that I would be fine with...but I am just leary of .002 being too snug. Sure hate to pull it all apart, it looks so good all sealed up and painted so nice...

Joel
 
If you have .012" and .020" is acceptable, why would you care about going the opposite extreme and possibly risk binding?
 
I don't think you would have a problem with binding. First, what is the maximum temperature the cluster gear would see? We know that gear oil starts falling down at about 200 Deg F, so let's assume 250 Deg F maximum temperature. The coefficient of expansion for high strength steel is .0000073 inches per inch of length per degrees of temperature increase. Assuming you measured the clearance at 80 Deg F, you have a 170 Deg F temperature increase. The cluster gear is 5 inches long. So, .0000073 x 170 x 5 = .0062 inch increase in cluster gear length. Accounting for the expansion of the case would give something less than .0062 inches required for clearance.

Bill
 
Good thought, and thank you for the math...I always like the numbers....I took the spacer out and will run er with .012" end play... it will be fine.
 
I also wonder if you would have any problem with the spacer.
I shot the temp of my ****** after a 20 mile drive on a 90* day and it was less than 100*.
 
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