Can BW35 Autobox fluid be removed using a suction pump

[johnnyanglia]

Hi, can anyone tell me is it safe to remove autobox oil from a BW35 using a suction pump? I am just a little concerned that I may damage the Internal pumps and parts, thanks in advance, Johnny

[JPB]

PM Harvey, he is the forum's foremost specialist on BW autoboxes and would probably be able to advise as to why the sump plug won't shift too. Last time I changed the fluid in the Dolomite's BW65 the plug was very tight and, as the sump is quite thin and not wanting to risk damaging that, I loosened the dipstick/filler tube, drained the sump, then refitted the tube.

[johnnyanglia]

Thanks JPB, will do, regards, Johnny.

[harvey]

Just thought I'd add the PM sent to me and the reply to it just to keep the thred up to date.

"johnnyanglia wrote:
Hi Harvey, I was advised to contact you. I have put ATF with Dexron in my BW35 autobox and ran it about 100 yards(the box was new). I then did not attempt to drive it for a year, I started it last week and although I was revving it, it would only crawl. Can you tell me if I have done permanent damage ?, I was thinking of removing the fluid via the dipstick filler tube and filling it with the correct grade of oil, Can you tell me if it is safe to do drain it this way or will I damage the box ?, thanks in advance, Johnny.


Hi Johnny.

Although DEXRON is not the correct fluid, and will cause damage in normal use over time, I don't think that driving it 100 yards would cause any problems at all as far as the use of that oil is concerned. If you want to change to the correct fluid you will need to drain off ( or syphon out) as much fluid as you can and refill, but you will need to do this several times as it's not possible to get the fluid out of the converter, so doing it several times increases the proportion of the correct fluid in there each time you do it. If the car has stood for a year it's quite possible that sufficient fluid has leaked out over time to cause a loss of DRIVE, although if this were the case you would lose REVERSE as well.
If the box was "new" then it must have been sitting around for ages, so it wouldn't surprise me if some of the seals, (in this case most likely the front clutch piston seal) have deteriorated and failed. If by "new" you mean reconditioned then I would guess that the seal has failed through incorrect fitting.

Check the fluid level first (get back to me if you don't know how to do it properly) and if req'd top up with ATF-G and then try again.

Regards, H

Only just seen about the sump plug/dipstick tube issue, but draining via either won't cause any problems, syphoning it out shouldn't cause problems either, but will take ages I would think, and need a long hose on the end of the syphon..