Triumph vitesse overdrive gearbox

[Joe c]

Hello

i have a three rail j type overdrive fitted in my vitesse

a single rail j type overdrive as come up for sale which I hear is stronger box ,

are both g/box the same length ?

I know about bellhousing  issue have a spare one to swap over  need to drill hole and find away of capping off we’re shaft comes through ,

is there any other fitting issues

[Clive]

No, the dolomite single rail is 1" longer. Prop would need shortening.

Also needs a clutch plate swap.

Main benefit is te larger mainshaft tip. But if this is an unknown box, buy with caution. 

[Joe c]

Okay thanks

when I fitted three rail j type  that was tight enough to fit 

so d type shortest box

then j type three rail   1 inch longer then d type

so single rail j type  2 inch longer then d type is that due to adaptor plate

 

[Pete Lewis]

the mainshaft tip diameter is the only real improvement on a single rail all other bits are very similar 

some parts hubs etc look to be  similar but can make a rattling good fit ( pending snychro problems if these are intermixed )

Just rebuilt Pauls Box and that seems to have 1st 2nd single rail hub  as a slack alice fit on the mainshaft but the right tooth count 

pete

 

 

[Clive]

7 hours ago, Joe c said:

Okay thanks

when I fitted three rail j type  that was tight enough to fit 

so d type shortest box

then j type three rail   1 inch longer then d type

so single rail j type  2 inch longer then d type is that due to adaptor plate

 

Ah, you may have a later single rail box fitted into a 3 rail case. A proper early dolly 3 rail box should be the same length as the d type (special short OD adapter plate)

Clue would be the fine spline input shaft/clutch plate.

[Joe c]

It definitely got the coarse spline it running on clutch from the original non overdrive box