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TR Trans Rebuild - Removal Of Overdrive Pump Cam?

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SVA614

Freshman Member
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I am dissembling at Triumph overdrive transmission (A type) for a rebuild. I have rebuilt a transmission in the past, but not with an overdrive unit.

I have removed the initial items following directions, information and reference from a Haynes manual, VTR maintenence pdf's, and an official Triumph workshop manual including the complete overdrive unit and subsequent rear adapter plate.

The overdrive "pump cam" that locates on the rear of the transmission mainshaft (behind the rear mainshaft bearing) - How do I remove it from the mainshaft? The only information I have found says "remove pump cam from mainshaft", or no reference at all to this issue. Do I need to remove it for the rebuild? Do I heat it for expansion to remove? How does it stay set in place in relation to the mainshaft (i.e. so it doesn't rotate on the shaft.

Any help or direction on this would be greatly appreciated.
 
Re: TR Trans Rebuild - Removal Of Overdrive Pump C

Hello SVA,

it simply slides off the gearbox output shaft, once the overdrive is removed, then just slide it off. It rarely needs to be replaced so just re-use it.

The difficult part is replacing the overdrive onto the gaerbox, be aware that there are two sections of internally splined overdrive internals that must be lined up or else you will probably crack the overdrive adapter plate as you pull the overdrive back onto the box with the two long studs installed for that purpose. If it goes tight do not keep tightening the nuts but remove the overdrive again and re-align the two splined parts. It can need lots of patience as you also need to put some wire or similar to hold the oil pump plunger down and turn the pump cam to minimum lift.

Alec
 
Re: TR Trans Rebuild - Removal Of Overdrive Pump C

Thanks for the reply. The pump cam is tight on the shaft. It won't just slide off. For the cam to drive the pump, it cannot rotate on the mainshaft, but must adhere and rotate with the mainshaft. How can it just slide off, but still hold in place on the shaft?

If it won't just slide off, any recommodations on how to get it off without damage?
 
Re: TR Trans Rebuild - Removal Of Overdrive Pump C

Just got it off. It did slide off with the help of a large spanner to use as a lever.

Thanks!
 
Re: TR Trans Rebuild - Removal Of Overdrive Pump C

Hello SVA,

they are not normally that tight; the overdrive keeps it in place once it is re-fitted.

Alec
 
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