Overdrive gearbox oil

[JSabah]

Anyone know the quantity of oil that goes in the gearbox with a J-type overdrive attached?

[classiclife]

Hello Josh,

I cannot give an exact quantity, but if you take a TR6 g/box with a J-Type OD then that is 1.5L.

The same car with an A-Type box will be about 2Ltr and with a D-Type it will be between the two .........................hopefully these figures may at least give you a starting point.

Sorry cannot be more specific than that.

Regards.

Richard.

[JSabah]

Thank you. That is an excellent starting point and my guess it that it will be accurate.

[A.N.Other]

I think it is at half as much again as the gearbox alone.

[classiclife]

Evening Colin.

Many people think classic gearboxes with or without OD take a lot of oil, in fact the opposite is true.

Many g/boxes without OD take less than 1L to fill.

I suspect that the figures quoted earlier will be close. If filling a completely empty OD g/box it may take a tad extra, but hardly significant against the capacities given.

Regards.

Richard.

[Vortex O'Plinth]

You may already know this Josh, but when the transmission is filled the level should be ½" higher up the gearbox dipstick than the original level mark. This should ensure an adequate supply to the overdrive. If the level is too low the overdrive may be very slow to engage or possibly not engage at all.

[JSabah]

Thanks for the responses. I filled it as mentioned above 1.5L or 1.68 quarts. (If I recall my numbers). Both the gearbox and the OD unit had been drained (the builder tapped a drain in the back of the OD unit so I am confident that all was empty. With the quantity suggested above in, I let it sit a bit and checked the dipstick. Exactly 5/8” above the full line. Maybe after driving it, it will go down to 1/2” above but I scored a new (full) mark for future reference at the 5/8”. I had so much time on my hands, I measured to the 1/2 ounce . Tunnel is modified and I should get a new, longer speedo cable later this week .... hopefully I’ll be testing it out by the weekend. FYI, being a LHD my cable was about 7”-8” short and Moss actually lists a TR6 cable 7” longer for cars with OD. When that is all done, I’ll get my speedo calibrated and the car will then be 100% (except for finishing the hardtop .... but I think I’ll leave that for the next owner)

[classiclife]

Hello Josh,

Being a Triumph owner, what I can say is that the TR6 & Vitesse OD g/box with a D-Type unit takes 1.35L / 1.42 US Quarts

I know you are running a J-Type but the difference between 1.5L and 1.35: will be reflective of the 5/8" & 1/2" respectively. This of course equates to the 1/8" height difference or in fluid terms 0.158 US Quarts.

Sounds as though you have made decent progress - well done.

Regards.

Richard.

[Ian Hastings]

Before you go to the expense and hassle of re-calibrating your speedo check it out on the road against another car or better still an app downloaded onto your phone. There are plenty available and they are very accurate.
I fitted a J Type from a Triumph 2000 and no calibration was required, although that might not apply for ODs from other makes/models.

[JSabah]

It is not the gearbox that is the reason for calibration... it is the rear end/differential.... which is the whole cause to start on this overdrive project. Standard rear end has a ratio of 3.58 (if I recall), and I have 4.11. I noticed that my speedo said I was going 60 in an area where I know traffic is much less. I confirmed the erroneous reading with a downloaded speed app on my iPhone