TR2/3/3A A-Type overdrive question

[RonR]

I have recently reassembled the two halves of the overdrive. I used a spare transmission main shaft to align the splines in the sun gear with the spines with the unidirectional clutch. The force needed to rotate the sun gear seemed excessive. I am wondering if the sun gear end float is insufficient, even though I reassembled the overdrive using the same thrust washer and adjusting washer that were in the overdrive when I disassembled the unit. These two washers set in front of the sun gear.

Any thoughts?

Thanks.
Ron

 

[TR3driver]

Seems unlikely to me, but IMO it's a good idea to check the end float anyway. Seems like it's often too large, which I suspect is what leads to breaking that little thrust washer that is trapped inside the planetary gears.

BTW, the early manuals say the sun wheel end float should be .014" to .020"; but it was later reduced to .008" to .014"

 

[RonR]

Thanks, Randall.
It really is difficult to turn. But it does turn
And 0.008 is not much clearance.

 

[TR3driver]

Shouldn't be difficult to turn, even with only .008" clearance. Half that is enough to turn freely. More likely IMO you've got a clutch dragging or something misaligned. Last time I had a problem, it turned out that the clutch facings had swollen (probably from leaving them in cleaning solvent too long) and so there was no position where they didn't drag. I wound up mounting the sliding member in the lathe and taking a very light cut to thin the direct drive clutch just a bit.

I learned the hard way, long time ago, that if something seems wrong, it probably is. Lots of folks will say things will "bed in" and free up, but it don't always work that way. Friction causes heat, which causes things to expand and try to seize. The results are often not pretty.

 

[RonR]

I have the overdrive back apart and it has way too much end float at the sun gear. With the sliding clutch removed, I can slide a 0.035 short feeler gauge between the front end of the sun gear and the washers (thrust and adjusting). While that is easily fixable with the right thickness of adjusting washer, it makes it evern more difficult to explain why the sun gear was so hard to turn with the overdrive completely assembled.

I thought maybe I had the brake ring installed backwards, but I doubt that I could have bolted the two halves together if that were the case.

Randall, how did you determine that the cluutch facings had enlarged?

Thanks.
Ron

 

[titanic]

Ron-By completely assembled, do you mean with the trans. attached? When the trans. is mated to the OD, the clutch (sliding member) return springs are compressed. This puts considerable thrust on the annulus and makes the flange hard to turn. Especially, if the return springs have been replaced. I was concerned about this when I rebuilt my OD, but wasn't really a problem.
Berry

 

[RonR]

Berry, only the two halves of the overdrive were assembled, not the overdrive mated to the transmission.
I did buy new return springs as the old ones were 8 different lenghts.

 

[CJD]

I've been following, but am a little unsure about what you mean when you say the sun gear will not turn easily. Are you saying when you insert the tranny output shaft into the OD that it is hard to turn?

In an un-actuated state, the drum locks the sun to the planets and ring gear, so the drive is straight through. I don't think the washers have anything to do with the tightness of turning the shaft. Any tightness would have to be one of the bearings...which would be the 2 on the tail shaft and the large pressure drum bearing. Do all of these bearings turn freely before you assemble everything? New tail seals can also have a good bit of drag...are you experiencing more than seal drag?

The only other thing that I can think of would be a warped drum. Have you looked at it closely to make sure it turns true?

 

[TR3driver]

Randall, how did you determine that the cluutch facings had enlarged?

Thanks.
Ron

I don't recall the entire process, but the proof was comparing the thickness to another clutch I had available. It was damaged in other ways, but the facings were fine.

Try grabbing the pins that the springs sit on, and see if you can move the clutch at all. ISTR there is a spec somewhere for how much it should move; but don't have my manuals handy.