TR4/4A overdrive question

[shoopal]

Hi all
I am restoring a 65 TR4A and my donor car is a 67 IRS with overdrive #22/61753
I saw that Moss listed a filter that was specific to that number and I wondered what else was different from the rest.
Also it seems to fit in OK (mounts, length etc) I know that I will have to mount the OD switch on the column.
Should I expect any other problems?
Thanks to all who have responded to my earlier questions.

 

[TR3driver]

61753 is the IRS version of the overdrive, with the smaller accumulator and several other minor differences. So the accumulator piston, rings, sleeve, spring are all different.

But I believe it should drop right in, fit the same and so on. IIRC the hydraulic pressure is supposed to be a bit higher though.

FWIW, I also believe the filter listing may be a mistake. At least the TR4 I bought in 1974 or so had the later style drain plug and filter etc even though it was clearly not a 61753 overdrive and did not have the IRS accumulator. Of course it's possible that someone changed just those components, but it seems like an odd modification to make. Even the plug in the pump was the later style without the tapped hole; even though the later filter would fit with the early plug.

The difference is that the early filter used a small bolt and spacer to fasten it to the plug in the pump; while the later setup just fit over a spigot built into the drain plug. Since the spigot is larger diameter than the bolt, the center hole in the later filter is larger. The early drain plug has a hex to turn it with, while the later one has 6 notches around the outside.