• 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)

"A" Type Overdrive Annulus End Float!!


Hello everyone,
I am rebuiding my "A" type overdrive on my TR3A and have a question regarding the end float on the Annulus. Before dis-assembly I checked the end float and it was 0.005". Pressed out the annulus & replaced the rear (small) bearing which seemed a little worn. Re-assembled the annulus into the casing using the same adjustment washer and now I have no end float at all. Question is do I go 0.005" thicker or thinner on adjustment washer?

Many thanks,



Jedi Trainee
Neil Google buckeye triumph technical. Good write up on A type assembly


Great Pumpkin - R.I.P
First thing of course is to make sure you've got the new bearing seated solidly both in the housing and against the adjustment washer.

Unfortunately, there is no way to tell whether you need to go thicker or thinner on the washer, unless you have the special tool (made of solid unobtanium). Here is a link to the article that Casey mentioned, which basically advocates a trial and error approach (trying different washers until you find the right one) https://www.buckeyetriumphs.org/technical/AOD/AOD3/AOD3.htm

My suggestion, if you still have the old bearing, would be to try to measure the difference in thickness between the old and new. I think, in this case, you should be able to lay a good straight edge across the inner face and use feeler gauges to detect which bearing isn't right.


Luke Skywalker
Country flag
I just went through all this last fall and this spring. Or, I went through it with the help of everyone here, and Randall in particular.

My end float went down to zero after rebuilding and replacing the bearings. I ignored that at first, and thought I'd check the operation on a bench test using a hand drill motor. When the hand drill motor wouldn't spin the output shaft very well, I figured something was wrong, and others here did, too.

So I tore everything apart and discovered that I hadn't seated the head bearing far enough against the annulus. I'd made two mistakes. First, I was too gentle with my Harbor Freight press. Second, I had used a wood spacer for the pressing, and I was likely misled by the compression of the wood. With a steel spacer I was better able to hear and feel the bearing popping into its correct place. Admittedly, a better eyeballing would have helped as well.

OK, with the bearing better seated, and then reinstalled the rear bearing the rechecked the end float. This time it was .003, but only by pressing my thumbs with some real force into the annulus and watching the dial gauge.

After some debate, I decided that was good enough. That conclusion came from: a) Others here not expressing much horror; b) my suspicion that replacing my 50 year old washer would be bad luck and just more fixing of something not broke; c) my hope that the new bearings would adjust and give a little play after some break in; d) my guess that my measurements weren't so perfect anyway; e) my hunch that a British car shop back in the '60s would have likely slapped it together and not bothered with measurements anyway; and, finally, f) so what if I break this apart and have fun again one day!

It's been running great for 480 miles, so unless bad things come fast without notice, I think I'm good.

Let us know what happens on yours, but I think Randall is right when he suggests you check the seating of the bearings and go from there.


Thanks for the comments. I'll check the bearing against the old one. I agree that maybe I was not agresive enough with the press!!
Similar threads
Thread starter Title Forum Replies Date
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
T TR2/3/3A Question on A-type overdrive solenoid Triumph 21
BillyB62 TR2/3/3A Type A TR3 Overdrive Wiring Triumph 13
T TR2/3/3A Question on A type overdrive spec for "clutch movement from direct to overdrive" Triumph 7
M_Pied_Lourd TR6 J Type Overdrive High Pressure Filter Cap-Major Problem Triumph 6
R A Type Overdrive reassembly question Austin Healey 3
R TR2/3/3A A-Type overdrive question Triumph 8
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
D A type overdrive question. Triumph 3
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
TR3TR6 J-type overdrive question Triumph 5
CinneaghTR A-type Overdrive Model Number Triumph 14
71tr J-type Overdrive Pressure Port Question Triumph 2
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
7 question after testing a J type overdrive Triumph 5
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