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Autogear Muncie pushing fluid out of the tail shaft seal

Posted: Mon Jul 04, 2016 8:25 pm
by 496blaze
I have a fairly new Autogear M23 4 speed in my 70 Chevelle that has been trouble free until recently. Last time I drove the car transmission oil came out of the rear output seal and coated my whole exhaust and underside of the car. I found the vent line that runs up to the bell housing sort of hung down and had oil trapped in it not letting the trans breathe so I shortened the line and made sure it was not plugged. Cleaned everything and went out and drove it, same problem. Next I changed the output shaft seal, same problem. This is all new stuff, trans, Strange driveline etc. What would cause this to happen? I do have a vibration that comes in at about 65 mph buts its not that bad. I am using Sta-lube GL4 85-90wt fluid.

Re: Autogear Muncie pushing fluid out of the tail shaft seal

Posted: Sat Sep 03, 2016 12:18 pm
by jimjamm65
there is no pressure in the trans extension housing to speak of. check your driveshaft yoke to see if it is the vented type. if it is, it will have a small hole in the cup plug which is pressed into the end of the spline tube. you will have to plug this vent to keep the oil from leaking out. vented yokes are used with some types of auto trans and are sealed with an o-ring in a groove in the output shaft. manual transmissions do not have this type of seal, so use non-vented yokes.

Re: Autogear Muncie pushing fluid out of the tail shaft seal

Posted: Mon Sep 19, 2016 3:03 pm
by autogear
Sorry I missed this till now;

We've seen some slightly oversized yoke barrels too. Call your builder and get them in the loop, if we built it; please let me know and we will straighten this out with you. Auto Gear assembled gearboxes used sealed ball bearings front and rear, which necessitates some sort of vent. If your builder used the OE-style, gland nut equipped input gear, sometimes the gearbox will try to vent out BOTH the threads of the nut AND the vent...this can cause issues. If your builder used the A.G. exclusive oilseal-equipped input gear, then the tailhousing vent is a requirement; although due to localized high pressure areas under the car it may need to be relocated using a hose.