black99ta

iTrader: (1)

Well, I bit the bullet and pulled out my M6 to rebuild. It's been popping out of reverse for a while. The teeth (the ones that engage the synchronizer assembly) on the reverse gear are worn so that they are round, but the straight part looks OK. So I have two questions for you expert rebuilders:

1. Can I leave that reverse gear in there? From what I understand the points on those teeth just allow it to slip into reverse easier (which it doesn't do anyway) and don't hold much of the load.

2. What caused it to pop out in the first place? The only thing I could see was the pads on the reverse fork were somewhat cracked. How can I tell if the fork is bent?


Thanks,

Joe

1madss

iTrader: (10)

It' a combination of the engagement teeth on the gear and the synchro slider that hold the tranny is gear. You also need to inspect the synchro slider for wear. If you don't replace the worn parts, it will continue to pop out and get worse over time.

The gear is $99 and the synchro is $89.

Has it been hard to get into reverse? Reverse is usually one of the gears that are hard to shift into if the clutch is not disengaging fully. Forcing the tranny into gear will tear up the teeth and the slider.

I doubt the shift fork is bent. It is steel. The only aluminum forks are 1/2 and 3/4.

Oh, I'm not an expert. I just play one on TV

Maybe somemore experienced folks will chime in as well

black99ta

iTrader: (1)

Thanks for the reply. It seems like the shaft that it rides on is worn a bit, is that what you mean by the slider? Where can I order those parts for that price?

calhoon

iTrader: (6)

if ypu have jumped out of reverse and the pads are worn you should replace the fork( and pads).Along with the driven gear and maybe the synchronizer.
The actual ratio of a gear drive is determined my the mech cutting but the load is carried through the clutch teeth - the little ones. If they are rounded they may not have enough back taper - what hold them engage - and that is why the jump out. The force on the fork in a jump out can bend it( why I said to replace it) . If the pads are just cracked , this prolly happened with the jump out. I suspect they are flattened/ extruded as well as cracked. This is the clue how it happened( the rounded teeth) . This is a classic example of missing shifts. Hitting reverse wil a significant forward speed. Yes, you crash through the inhibitor and attempt a reverse shift. Good news is it does not engage( THAT would be a wild ride!) but is does clash the synchrinizer/ clutch teeth. Enough of this will wear out the tooth tips and start to make shifting reverse ( when intended) hard and , as it progresses, block out. Ultimate ly , the wear will damage the tooth enough that it can no longer hold the engagement.

black99ta

iTrader: (1)

That sounds about right to me, but can that fork reallly be bent? It looks pretty darn sturdy too me. Is there any way to check it?

1madss

iTrader: (10)

For the parts try either The Gear Box or D&D.

The slider is the outside portion of the synchro. It is a ring that slides up and down on the synchro hub. The if the slider is worn the entire synchro must be replaced.

technical

I have never taken apart a M6. But I've done other tranny's and reverse was never synchronized. This would be the first time I've ever heard of a reverse gear being synchronized. Has this been changed in the M6?

1madss

iTrader: (10)

Yes, the T56 has a reverse synchro.

calhoon

iTrader: (6)

Any modern( post 70s) manual should have a synchronized reverse. The sliding Idler boxes have that characteristic gear howl in reverse and are generally not synchronized( but are the 70s stuff). These are the cheapo boxes or trucks ( or both). All T56s are fully synchronized.

technical

T-5's aren't.

calhoon

iTrader: (6)

T5s are 70s stuff ( Chevette)

technical

I had one in my 90 Camaro

calhoon

iTrader: (6)

So...

technical

I didn't think it was that archaic to have a non-synchronized reverse gear.

black99ta

iTrader: (1)

....hmm I think we're getting a bit off subject, but I do appreciate all of the responses.

The M6 certainly has a synchronized reverse gear since I have the transmission apart and have both seen and touched the synchronizer. This is proof enough of existence for me.

The real question is: Is there a way to determine if the shifter fork is bent? Is there a certain face that should be flat that I can check with a flat surface and feeler gage?

1madss

iTrader: (10)

This first place that I would look is at the area where the shift fork rides on the rail. It should fit tight around the rail and not wobble. Give either D&D or Gear Box a call and they should be able to help you figure out if you need a new fork. If you do, I think they are around $50.

black99ta

iTrader: (1)

madss I think you're right. I checked the fork and it seems OK. The rail that it pivots on, however, looks worn. Maybe that's where the slop is coming from. How much are those to replace?

John98LS1

iTrader: (6)

this is not true, the reverse gear is a unsynchronized gear. ask any tranny builder

pontiac

iTrader: (4)

cool guy ........YOU ARE WRONG
reverse IN A T56 transmision has a synchro!!!!!!!! it is the only one that is brass 1-6 are carbon and reverse is brass if you still don't beleave me I can take a pic of it just to prove it. I have all the parts I just replaced in my tranny setting out on my table now IT HAS A SYNCHRO.
make shure you know what you are talking about before you post up a quote and call them wrong.

pontiac

iTrader: (4)

The one I am pointing at IS REVERSE.
the other is a carbon one