synchronizer
 

How do you tell if a synchronizer is bad by looking at it? I know about it jumping out of gear but what about one that's apart,what should I look for?

Re: synchronizer
 

Look at the teeth on it, they should be nice and pointed, the square notches should be straight and square. Also look on the ring and you should see the machined lines and feel them with your finger tip.

Re: synchronizer
 

There are other things that can cause a transmission to be forced out of gear mesh under load. Synchro blocker rings may not be your problem. The blocker rings teeth can get chewed up, window slots get worn larger and internal tapers get excessively worn. You may have a problem with the counter shaft cluster gear. It may have too much axial play due to wear on the thrust face area or the bearings may have too much radial play. I usually check that stuff out first when it pops out of gear.

Mac VanPelt has a wonderful transmission repair book for the old Ford transmissions that is worth every penny of the purchase price and then some.

Re: synchronizer
 

The outer hub, two ends have pointed teeth to match the small gear teeth, they often get mushroomed out with wear.

Re: synchronizer
 

I did notice what seemed like excessive play in the counter shaft, that might be some of the problem. I just took it apart to use the 1st gear slider and reverse gear in my 41 but thought I'd look into what was causing 2nd gear problem as eventually I am going to rebuild this one also. Thanks to everyone for tips.

Re: synchronizer
 

I look at the following before I lay blame on a the synchro; the end of the input shaft which locates in the pilot bushing in the flywheel, the inner bearing surface which pilots the mainshaft (uses 1.125 OD x .75 ID roller bearing), the mainshaft end (.749 min. dia) and the 2nd gear bushing. The synchro's only function is to slow the gears during shifting, not to support the shaft assemblies as is sometimes implied..........oh, it just needs new synchros.........that's the problem!

The trans shafts are supported on 4 bearing surfaces, the pilot bushing/bearing, the input shaft ball bearing, the mainshaft roller bearing and the main shaft ball bearing at the rear. I feel the pilot bushing and roller bearing are highly important as well as end play in the mainshaft assembly within the case.

Good luck,
Paul J.

Re: synchronizer
 

If it is a top loader, the detents can also cause it to pop out of 2nd gear under load as well.

Re: synchronizer
 

"How do you tell if a synchronizer is bad by looking at it?"

A key function of the synchro is that it rides on the coned surface of the gear. The closer the brass synchro teeth are to the steel gear teeth the less likely the contact surfaces are going to cause the synchro to function and "pick up" the gear's rotation.

Synchros can stretch as well as wear. They also can be switched around ... an original synchro just ... maybe ... be better than a POS new one.

Take your MDG and some synchros, new and used, and play around with them. See how they feel/understand their function.