• Hi Guest! Being a Paying Supporter is NOT a requirement to participate at BCF. However, subscribing will help ensure we can continue to serve the LBC community for years to come. If you enjoy BCF and find our forum a useful resource...Please consider supporting us by **Upgrading**
    (PS: Subscribers don't see this banner)
Tips
Tips

TR2/3/3A A-Type overdrive question

RonR

Jedi Trainee
Country flag
Offline
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

Great Pumpkin - R.I.P
Offline
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"
 
OP
R

RonR

Jedi Trainee
Country flag
Offline
Thanks, Randall.
It really is difficult to turn. But it does turn
And 0.008 is not much clearance.
 

TR3driver

Great Pumpkin - R.I.P
Offline
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.
 
OP
R

RonR

Jedi Trainee
Country flag
Offline
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

Jedi Warrior
Country flag
Offline
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
 
OP
R

RonR

Jedi Trainee
Country flag
Offline
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

Yoda
Country flag
Offline
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

Great Pumpkin - R.I.P
Offline
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.
 
Similar threads
Thread starter Title Forum Replies Date
T TR2/3/3A Question on A-type overdrive solenoid Triumph 21
T TR2/3/3A Question on A type overdrive spec for "clutch movement from direct to overdrive" Triumph 7
R A Type Overdrive reassembly question Austin Healey 3
D A type overdrive question. Triumph 3
TR3TR6 J-type overdrive question Triumph 5
71tr J-type Overdrive Pressure Port Question Triumph 2
7 question after testing a J type overdrive Triumph 5
H TR4/4A A-type overdrive pump Triumph 4
Got_All_4 TR6 Refurbishing gearbox with A type overdrive Triumph 7
D TR2/3/3A Type A overdrive not engaging Triumph 0
D TR2/3/3A Type A overdrive not engaging Triumph 16
M TR4/4A A type Overdrive Oil Leak Fix Triumph 3
Graham H TR2/3/3A A type overdrive Triumph 6
KVH General TR Type A Laycock Overdrive Questions Triumph 8
C TR2/3/3A A-type overdrive drain plug oring Triumph 1
J TR4/4A TR4 A Type Overdrive Part mixup Triumph 4
CJD TR2/3/3A A type Overdrive Seal Triumph 9
T Spitfire J Type overdrive Triumph 2
BillyB62 TR2/3/3A Type A TR3 Overdrive Wiring Triumph 13
M_Pied_Lourd TR6 J Type Overdrive High Pressure Filter Cap-Major Problem Triumph 6
T TR2/3/3A My A-Type overdrive rebuild project, some questions Triumph 36
T TR2/3/3A Will Spitfire D-type overdrive work in TR3 with TR4 transmission? Triumph 3
R Overdrive [Type A] brake ring gaskets Austin Healey 1
R TR2/3/3A Overdrive [Type A] Brake Ring Gaskets Triumph 14
J General TR D Type overdrive not working need suggestions Triumph 5
Gordon_Dedrick TR2/3/3A A type overdrive installation Triumph 7
T TR2/3/3A Type A Overdrive, Physical Differences between Roadster Brands? Triumph 2
T TR2/3/3A Type-A Overdrive Handling Differences Triumph 9
A TR5/TR250 A-type overdrive questions Triumph 25
71tr TR6 Overdrive Mount / J-type on A-type frame Triumph 1
D TR6 76 TR6 J Type Overdrive Triumph 7
Gordon_Dedrick Testing an A type overdrive Triumph 20
Simmo I need help with J Type Overdrive Triumph 15
Q "A" Type Overdrive Annulus End Float!! Triumph 4
John_Mc J-Type overdrive for sale on CL Triumph 4
KVH More on A Type The Overdrive Triumph 2
Coyote1 J Type Overdrive engage problem Triumph 3
J A Type Overdrive Triumph 17
K TR6 TR6 J Type Overdrive...Link to Schematic? Triumph 3
O J Type Overdrive Conversion Triumph 19
Marvin Gruber J type overdrive unit on BCF classifieds Triumph 2
HerronScott TR4/4A TR4A A-type overdrive and Moss Europe TR2-4A cat. Triumph 2
T A-type Overdrive & Gearbox Triumph 9
CinneaghTR A-type Overdrive Model Number Triumph 14
T A-type overdrive / gearbox trouble shooting Triumph 69
R_Lyle TR6 J-Type or A-Type Overdrive for 1972 TR6 Triumph 18
TR4A_IRS Looking for a J Type Overdrive? Triumph 0
mgedit Fluid for J-Type Overdrive Triumph 22
Got_All_4 A type overdrive that has been sitting for years Triumph 6
Tinkerman Type A overdrive Triumph 7

Similar threads

Top