Overdrive ID

[torque2me]

Hi all,

Anyone with a 1973-1975 parts book? My 1978 one does not show part number 313241.

The part is a GKN Laycock overdrive. The cardboard it is wrapped in has Dolomite Sprint written on it with felt marker. Inside, tied to the o/d is a luggage label with 313241 2.5pi written on it. The GKN metal ID plate says J-Type with a serial number.

Can anyone provide a definite? I always thought that o/d's were all one type and were the same whether fitted to Jaguar, TR or Dolomite (no knowledge about Rootes Group fittings/types). But as usual I've been disabused of that notion. An A-Type for a Jag might have slight differences to one fitted to an early TR (guess flange wise but other?) and the same with J-Type. My teacher warned me Sherpa van J-Types have pipe differences.

Guess most of you know all that but I'm new to the party. Only have had one issue with a J (blocked filter) and thus never had to expand my knowledge with regard o/d types

Kev

[Charles H]

1975 parts book only shows UKC0800 as a recon J type OD unit, my earlier parts manuals only show the A type OD box.

[torque2me]

1975 parts book only shows UKC0800 as a recon J type OD unit, my earlier parts manuals only show the A type OD box.

Thanks for that post Charles. I guessed it would be in the 73/74 era but hoped for something more definite. Need to look at a Dolomite parts book next maybe?

Kev

[Charles H]

Post a photo of the plate on the unit if you can. May help us ID it.

[Alec]

Hello Toprque2me,

my parts book, (RTC9064/A August 1975) shows 313241 as being an overdrive (J Type) for a 2.5 P.I., 313239 for a 2000, and RKC0155 for a 2.5 carburettor model.

Differences may be as little as the number of internal springs for the clutch? Without checking the workshop manual I don't think the ratios were different?

Alec

[Mike Stevens]

There are differences in internal oil pressure dependent on 2000/2500TC/S/2.5PI all set by the relief valve inside the O/D. That would account for the differing part numbers.

Another way to check is to compare the parts book looking for the 'square', 'triangle' or 'circle' which are used to denote which vehicle type!

Cheers,
Mike.