Re: Noisy transmission

Posted by Bob Carabbio on March 14, 1997 at 13:40:43

In Reply to: Re: Noisy transmission
posted by Marith McCoul on March 13, 1997 at 11:42:59

In neutral the only gears in mesh are the Pilot shaft/countershaft with no load, and the reverse idler.If it’s noisey then, the countershaft must not match the pilot shaft very well.Like Marith says,different gear sets tend not to cooperate terribly well after 60 years of selective wear. The lockout plungers are also definitely a thing to look at, since if they haven’t been replaced, they will need to be.
There is a service bulletin that listed a change in the rear main shaft diameter and spline width to a larger size to create a tighter fit, and eliminate jumping out of "intermediate".If an earlier main shaft were used with later gears plus 60 years of wear, who knows.The shaft diameter was changed from 1.2465-1.2475 to 1.2485-1.249.The corresponding internal spline on the gears was also up-sized by 0.0005" to match.The main shaft and sliding gears were to be selectively matched for close fit.
The is a pilot bearing with the multiple disk unit, but typically problems there will make the tranny jump out of high.My first "A" was a ’28 AR Tudor.The engine burned oil, so I used an engine out of a Depression tractor, and swapped pilot shafts and main bearing retainers with the tractor tranny to interface with the single plate clutch (this was 1958 after all). Never had a problem until three years later when I knocked a tooth off the second sliding gear dragging with a VW beetle (I won).
Actually there was no change in the cluster gear, from early to later, but the transmission case was changed in January of '29 bringing the countershaft bosses in about 1/16" each to eliminate the spacers.Your early tranny should have the wide bosses requiring the spacer washers.If the cluster gear has about 1/8" end play, your spacers are missing.End play of the countershaft could cause the second to jump out.
The "Pocket Bearing" between the pilot and main shaft should be checked for excessive wear on the pilot shaft cavity, and the main shaft pilot since clearance here would mis-align the second gear/countershaft mesh. If seriously worn, Torrington makes Bearing assemblies which could be applied instead of the stock Hyatt bearing with some machining. The pilot on the rear shaft is 0.750 dia and the cavity is 1.125".If the rear shaft pilot is gone, turn it 0.5003-0.5006, and press on Torrington #IR-081212 inner rings (2).Leave a 1/8" shoulder on the pilot for the spacer ring to ride on.If the cavity is also gone, turn it to 1.2487 - 1.2497 and press in Torrington #HJ-122012 Needle rollers(2).Make sure to drill oil holes to line up with the grooves in the needle assemblies.
Bob Carabbio

E-Mail Comment to Webmaster