dg250 front seal

[jerry_hoback]

Hi all,
While I am still dialing out the most aggressive leaks on my car, I got 2 new ones. One was a cracked speedometer cable housing, a Relatively easy fix. But now as I top the trans back up, I have a leak out the front of it at about a drip per second. Ive taken the torque converter cover off and it appears to be the front seal, or one of those O-rings on the front pump. Research thus far shows that I can remove just the gearbox assembly without disturbing the torque converter or its housing. Please correct me... I anticipate that this will be a very trying project what with me in my mid 50s and no lift in my garage, so I got the service manual for this unit and plan to poke around the gearbox a bit while I have it out to the extent of adjusting bands and checking other points of dampness.
Coming to the point- The service manual shows a "spline alignment fixture" on page 29 under Removal and Installation in my copy. The tool number is shown as j.4283 (or BW5). I dont understand the use of this tool. It appears to be used on both the gearbox and the converter, but I dont follow as to what it does. To change the seal and the O-rings, I will need to be in behind where it is shown. Is this a tool which is Absolutely Needed? Or what will happen if I dont use one? surely Im not the first.......

[cass3958]

First are you sure the it is a leak? I ask because I once questioned a leak on my gearbox shortly after I had had it rebuilt by a specialist. He checked it out could not find anything and then asked how long the car had been sat before I noticed the leak. The car had not been run for a month or so and he stated that the leak was possibly due to the torque converter emptying back in to the gear box. The level on the Auto box should be set with the engine running and oil in the torque converter. When the car sits for a while the oil from the torque converter returns to the gearbox taking it above the normal operating level and you start to get small leaks above the sump level. The speedo cable it a typical area for the leaks to show.
The gear box can be removed leaving the bell housing and torque converter in situ. This is how my garage did it. Long story short I wrongly assumed my gearbox was working and driveable when I bought the car. The car was none running when I bought it and so having rebuilt everything apart from the gearbox I assembled it all and then found once I started driving it that the gearbox was knackered. Rather than pull the engine the gearbox was removed from under the car leaving the torque converter and bell housing in place. There are on the BW35 which I have to inspection grills in the bottom of the bell housing and by putting your hand in here you can undo the bolts that hold the bell housing to the gearbox. Expect lots of oil to come out of the torque converter as you pull the gearbox away. See the photo below of the bell housing still in place under the car.
As for the tool you describe I can't help you there and my only guess would be that it is an alignment tool like they use on a clutch but I never had one when I connected the gearbox to the engine/torque converter and I am still alive. If you are not removing the torque converter from the engine is it required?

[jerry_hoback]

Good question on my certainty- I try to use the car by at least running the motor if not enjoying a drive around my area every week to 2 weeks. The speedo housing broke when I put it in reverse to back it into my garage. I could see where the drip line started on my NEW concrete. The front of the gearbox has always been "wet" while the converter is consistently "not wet." I do try to keep my eye on it as I dont want it to self destruct. Till recently, if I drove it to work, and put my diaper under it, there would be 1 or 2 drips during the course of the day. I was ok with this, as I was able to use the car. I will absolutely get a flashlight under there before committing myself. After replacing the cable (which did fix that part of the drips) I was topping it up as the manual describes, motor running, car in Low. As I added fluid I would stop every pint or so to go around and run it through the gears. The leak started as fluid reached the tip of the dipstick in the engine bay. It also stopped when the motor stopped. I see your thought about dripping from the back of the converter, but as I have seen, the converter is not "clean" by any means, but has not had fluid running off it. Is there a point on the shafts where it could leak beyond the seal? Your pics show several things I was wondering about. Your car is the perfect color for viewing examples! Thanks for posting them.
As far as the "fixture," I was suspecting that its a finesse tool perhaps used to set the corresponding splines in a line to ease installation. The pics show it bolted to the same relative hole- gearbox to housing.

[John Quilter]

Looking at the DSCF8354 photo above I see you have removed the bellhousing after the gearbox was out. So it is possible to get the many (too many) bell housing to engine bolts out. Just wanting to confirm. And this is a BW35 unit not a DG250?

[cass3958]

You are mistaken but I can see why. The bell housing is in situ in both photos, it was not removed from the engine. The photo gives the impression the bell housing has been removed only because it is a straight on shot and the flash alters the perspective. The bell housing and the Torque converter stay attached to the engine. Getting to the upper bolts between the bell housing and engine block would be very difficult if not impossible. There is just no room. Having said that you could drop the front subframe, remove the prop shaft, exhaust, rear stabiliser and engine mounts and lower the engine and gearbox down far enough so you can reach the bolts but if you were going to do this you may as well drop the engine out and do the work on a bench.
My car does have the BW35 gearbox not the DG250 but as far as I know access to remove is the same.

[jerry_hoback]

Sorry for the delay. My leak was not the front seal per se, but rather the large o-ring that the front pump is mounted against. Some other antagonist had been in there previously and smeared the area up with silicone which of course had worked loose over time. That entire project scared me deeply, as transmissions are something I actively try to stay out of. In the end, I replaced that large o-ring, the smaller one inside of it also on the pump, and the front seal as well. I was able to remove the gearbox without removing the bell housing and also did not need the special tool that Jaguar calls for in the manual for that transmission to align the splines on the shafts. While I had the unit on my bench I adjusted the bands which were all quite loose. The large o-ring did not appear to be available separately by part number but I was able to get one of the correct dimension from a place called (of all things) "The O-Ring Store" online (I was required to buy 5 to make a minimum purchase amount). Thanks to Cass for posting visual proof that the gearbox could be removed on its own. The unit is back in the car AND still works. The shifts are much better and I have not seen a transmission drip yet after 3 weeks of light use.

[cass3958]

Nice to hear Jerry and helping with advice and photos is what the forum is all about.

[Orlando St.R]

Thanks for that very useful information, Jerry, and well done on your achievement. Like you, I try to stay as far away from transmissions as I can, esp the DG250!