So I have been ever so slowly tinkering with my 3.8 MK2 Auto, in between numerous other jobs.

I have the brakes all rebuilt, electronic ignition fitted and have the carbs rebuilt and tuned to a stage where its driveable.

Now its time to address the elephant in the room, the auto trans, it appears to leak from every seal possible, the parking pawl jumps, there is a definite delay when putting it into gear, it slips and judders when it actually engages, but still moves the car around.

So firstly I need to work out what transmission it is, I've been told there is two main ones, the BW35 and something else. I will crawl under the car soon once I have gained some more identification info. Any help here would be greatly appreciated.

I'm sure a few of these issues could be rectified by just tightening the band adjusters and adjusting the cables to the correct length, and I might still do that initially to see if it helps, but the oil leaks alone and the uncertainty of its age make me want to rebuild the unit properly. The engine isn't a matching number unit, so I have no idea what or when it was changed.

It's something I'm happy to undertake, and these days there is plenty of detailed information on how to perform such intricate tasks

Here is a very detailed BW35 rebuild post for example
BW35 strip and rebuild in pictures | Rover P5 Club Forum

However, I dont have a workshop manual, and was wondering if it is even possible to remove the auto in situ? Without dropping the front subframe, and then the whole engine/trans as a unit.

If I wasn't just working on a concrete floor carport, and had access to a decent shed and hoist, i'd drop the subframe without a moments hesitation, as future plans include a full re-bush and powdercoat of all suspension components, but space restraints limit me currently to how much I can spread a car around.

 

The early Mk2 used the Borg Warner DG250, later replaced by the BW35. The DG 250 was also used by a number of British cars and by Studebaker in the US. You can still get a repair kit from some suppliers. (Transmission: DG250 in Jaguar)
Mine was a 2 speed only when I got the car, with the usual broken parking peg, and leaking like a sieve. My local transmission guy tried to rebuild it twice, each time with a life span of 20 miles. The problem with the DG250 is that it does require a lot of knowledge to install it properly. Finally I decided to bit the bullet and I bought John's Cars conversion with uses a 4 speed with overdrive GM 700R4: a modern no problem transmission that let me drive on Highways at a reasonable speed and reasonable rpm.
The kit is good, but not perfect, meaning that you have to know your way around transmissions, and be prepared to do some tweaking. But it's a pleasure to drive. Cost would be $4000 to $5000 depending on how much work you do yourself. 700R4 rebuilt start at probably $1200. You can check: Transmission Rebuilding to get an idea bout DG250. John's cars:Jaguar conversions, swaps, parts, service and advice - from John's Cars in Dallas.
You can also conver it to a manual transmission.
The DG250 and other auto transmissions (and the 700R4) can be removed and refitted with the engine "in situ".
JP

 

For that price, i'd get an adapter plate and fit a modern manual gearbox.

So after posting this I had some spare time, I did some more research and then crawled under the car to find out its the Borg Warner BW35 auto.

So I firstly adjusted the bands to specs, they were considerably loose, and topped off the fluid again, definitely helped the gears engaging, but the oil leaks alone make me feel it a worthwhile venture to reseal it at the minimum.

Unfortunately I blew a welsh plug out the side of the block after a few minutes of driveway idling and fwd/reverse driving.

I'll suss out what seals I can change easily, with the box still in place, change them along with a filter change/fluid flush and see how it is after that.

I'm not ready to do a complete strip down of it, time and space restraints don't allow that right now.