Mating Overdrive to Gearbox

[mylesw]

So here I am again trying to mate the overdrive to the gearbox and have been trying to do so for over a week. OD hangs up about a cm short. It's engaged on something as I have to give it a good yank to get it off again. Oil pump has been tied with a piece of string so it's not that which is causing the issue. Splines have been aligned as best I can and look good to me with the naked eye. But it still will not go on. Overdrive is new, gearbox has just been rebuilt. So what to do next? I am thinking about disassembling the gearbox again at checking that the mainshaft does indeed fit in the new od. Surely it couldn't be the case that the splines in the od don't fit my mainshaft...? What should I do...persevere with it? Disassemble to gearbox...? Or try to find a specialist to do it for me...? Suggestions gratefully received....

Myles

 

[Healey Nut]

Take a long fine blade screwdriver and use it to "feel" the splines inside the OD unit . They have to be aligned exactly or you will encounter the problem you are having . Once aligned slip it very carefully into place over the output shaft . DO NOT FORCE IT !!! it should slide all the way in before you put the nuts and bolts back in . Once is on sit back relax and celebrate with a beer .

 

[Keoke]

find a specialist to do it for me.

It usually is not that much trouble so a specialist may see the problem right off and save you the wear and tear.-Keoke

 

[philstr6]

Myles
Dry Run try to mate the overdrive without the spings and cam,if it slips all the way on,then you know that it will work with the spings and cam in place,also when you have the splines in line,dont move the rear flange at all
Phil

 

[vette]

here is an excellent article on the OD, maybe you can find the answer here? I can't tell you exactly where because I have not finished the article myself.
https://www.buckeyetriumphs.org/technical/AOD/AOD4/AOD4.htm
Dave.

 

[mylesw]

Still having fun with this. Got my dial gauge out this morning to check that the output shaft was centralised. The dial moved up to 2 thousands of an inch which seems like nothing to me. But could this be my problem...?

Thanks

Myles

 

[Healey Nut]

If it came off it should go on . the .002 runout shouldn't matter . You have a spline alignment issue or possible the sunwheel thrust washer is not aligned . Do you have access to an old output shaft to use as a dummy and try it on a workbench .
Is the gearbox in the car or do you have it out and standing vertical on the floor ?

 

[mylesw]

Gearbox is out and vertical on the floor. No access to a dummy shaft although not really looked yet. Overdrive is new refurbished replacement so not the one that came off...

Myles

 

[Stretch]

Check that the oil pump roller is not hanging up on the side of the cam. Also try some different alignments of the rear splines. Sometimes they are just a little off such that some alignments are better than others.