HerronScott
Darth Vader
Offline
So I didn't realize the TR4A had a different A-type overdrive assuming the following information from the Moss Europe catalog is correct. I think this was a change in the accumulator.
OVERDRIVE UNIT, (series 22/61275) TR2 To TS5979
OVERDRIVE UNIT, (series 22/61374) { TR2 From TS5980, TR3-3A} TR4 (To October 1964)
OVERDRIVE UNIT, (series 22/61712) { TR4 (From October 1964)} through TR4A solid rear axle
OVERDRIVE UNIT, (series 22/61753) TR4A IRS
Note: Overdrives can be interchanged as complete units. It is not recommended that 22/61275 is used on later cars, as it is hydraulically incapable of handling any ‘extra’ torque, especially in 2nd and 3rd gears. It is, however better than nothing, and if used on later cars should be restricted to 4th gear use only. 22/61753 is the only safe unit to use on the TR4A IRS, as none of the earlier units feature the ‘cushioned’ engagement. This modification was introduced in 1965 to smooth out engagement, it also lessened the likelihood of the engagement to rip the differential mountings off the chassis.
I found Moss's Restoration catalog to be pretty interesting and wouldn't mind have a printed copy.
Moss Europe TR2-4A catalogs
cott
OVERDRIVE UNIT, (series 22/61275) TR2 To TS5979
OVERDRIVE UNIT, (series 22/61374) { TR2 From TS5980, TR3-3A} TR4 (To October 1964)
OVERDRIVE UNIT, (series 22/61712) { TR4 (From October 1964)} through TR4A solid rear axle
OVERDRIVE UNIT, (series 22/61753) TR4A IRS
Note: Overdrives can be interchanged as complete units. It is not recommended that 22/61275 is used on later cars, as it is hydraulically incapable of handling any ‘extra’ torque, especially in 2nd and 3rd gears. It is, however better than nothing, and if used on later cars should be restricted to 4th gear use only. 22/61753 is the only safe unit to use on the TR4A IRS, as none of the earlier units feature the ‘cushioned’ engagement. This modification was introduced in 1965 to smooth out engagement, it also lessened the likelihood of the engagement to rip the differential mountings off the chassis.
I found Moss's Restoration catalog to be pretty interesting and wouldn't mind have a printed copy.
Moss Europe TR2-4A catalogs
cott