THE INTERNATIONAL JAGUAR 'S'-TYPE REGISTER FORUM

As a member of the Rover P6 forum, Gear oil for the Borg Warner 35/65 is a hot topic and to that aim they have imbedded on the Forum that ATF-G to ford spec M2C-33G should be used and NEVER use oils with Dextron as they could ruin the gearbox. Apparently Dextron oils have additives that would make the clutch plates slip and burn out. I would think that this also applies to the DG box also.

Regards John

1B1257BW

Build date 24th April 1964

As an oil company man I can assure you that the cautions are valid. All automatic transmission fluids, and there are many, contain friction modifiers and are blended/formulated to allow controlled slip & lock up of the clutch packs for desired minimum levels of shift shock. At the same time they require to ensure long service life of the transmission.

Put in layman's terms if you use an over slippery fluid in a transmission designed for quick lock up you will overheat & burn out the clutch packs. Likewise if you place a fluid like Fords M2C33 F or G in a transmission designed for e.g. Dexron II you will suffer severe shift shock.

Always use the OEM recommended fluid. The fluid is a design component of the transmission

My dad used (quite a lot of) Castrol TQF in my DG gearbox back in the day. But, like so many oils, although the name has remained, the formula has changed.

Although the 35/65 specified a Type F fluid, the DG specified Type A fluid, which is pretty hard to find these days. I went through all of Jaguar's original recommended fluids for the DG gearbox in the Operating, Maintenance and Service Handbook and not one of them is available today in its original formulation. [Update 7/2/19: Jaguar TSB FF23 of April 1969 recommends M2C 33F (Type F) ATF for all gearboxes, including the DG. See my post below].

I have been using Dexron II since the car was back on the road, as recommended and installed by Graham Whitehouse, who looks after most of the remaining DG gearboxes in the UK and beyond. So far, so good. The DG change from low to immediate is quite harsh at the best of times, so Dexron II does soften that transition slightly. As to how long the box will last with that fluid, we'll have to wait and see. Hopefully Graham Whitehouse will still be around to rebuild it if/when the clutch packs wear out.

Type A Suffix A Transmission Fluids are difficult to come by. Benz still requires them as a manual transmission fluid in old trucks.

It is possible that the gent that rebuilt your box has in fact changed the clutch pack friction material away from OE.

Trivia:

Original Type A Suffix A fluids used Cold Sulphurised Sperm Whale Oil as an additive. After the whaling ban we had to synthesize the stuff.

Love the trivia

there is Type A and Type F available on eBay. Whether it is the same as the old types I wouldn't know.

Orlando, do your mean Greg Whitehouse of www.gwautos.com or is Graham Whitehouse someone else?

I have been using STP Type F in the gearbox and PS reservoir for years. Is that a good choice?

M2C33F or G products are the very best for Power Steering on our S Types. They were designed to hold together a particularly fragile range of Ford transmissions & offer really superior wear protection as a result. To be used if you want long life from your PAS pump & box.

I think my DG box would run immeasurably better with a dose of sperm whale oil. . That's such a brilliant - and even in the 1950s - surprising fact.

Yes, I do mean Graham Whitehouse of GW Autos.

Glyn Ruck wrote: ↑Sun Feb 03, 2019 9:28 pm M2C33F or G products are the very best for Power Steering on our S Types. They were designed to hold together a particularly fragile range of Ford transmissions & offer really superior wear protection as a result. To be used if you want long life from your PAS pump & box.

Does this grade of oil in the PAS make it leak more or less?

After topping it up for ages and continually getting underneath with a clean rag to wipe off the drips I can across some stuff in online which is designed to stop leaks in PAS systems. Made by Lucas it is called strangely "Power steering stop leak." Poured the stuff in the PAS reservoir and not had a leak since.