Join Date: Dec 2001
Location: Belleville, Illinois
Thanked 22 Times in 17 Posts
Re: trnas pops out of 3rd...
Not with a T176, but I did have the problem with a T10 once, and with an old 3-speed before that. There are two likely causes; either it's not being shifted all the way into gear, or it's worn out.
A common cause is excessive end play in the gears on the mainshaft. With the helical cut of the gears, they want to shift fore and aft every time you go from coast to power. That motion can work the dogs out of engagement.
Badly worn dogs can do it too, but then it's more likely to happen when applying a lot of torque. If the shift forks or linkage are worn or bent they might not get the dogs fully engaged.
Sometimes the body can shift or sag on the mounts and block the shift lever from getting all the way into gear. If that's not the case you'll probably have to remove the box and inspect it.