BW65 leak

[APS]

Hi guys over the course of the winter when I had my car laid up while I refreshed the rear suspension I have lost quite a significant amount of atf from my bw65 gearbox. Thankfully I had a large 2 foot by 4 foot double folded piece of cardboard under the car and it is absolutely saturated in atf.

I cleaned up the gearbox with brake cleaner as it was not obvious where the leak was coming from. I had read on here that the selector seal is a usual suspect, but left overnight I can see that I have a significant leak from the speedo drive. The picture attached shows the leak after only a few minutes of cleaning it dry. I have not found much in my search on here for this. I am not sure if this is the only leak, but I need to stop this first before I go any further.

I see from part suppliers that there is a seal and a couple of o rings in the housing.

So question I have is are there any gotcha’s if I remove the speedo drive from the housing ?

Am I likely to have a flood of aft when I remove the seal ? Are the seal and o rings easy to remove and replace ?

I have just come to realise that the rom I got with the car does not cover the bw65.

Is it safe to start the car, not drive it just start it, if the amount of atf is very low ?

Thanks in advance for your wisdom.
DE68EEA7-798F-4732-88DD-900EAC5C84D4.jpg

[022Dave]

There’s been a recent post on here about oil leakage from an overdrive speedo cable, whereby a copper washer sealed the leak. Not sure if it’s same on the BW ‘box, but worth looking into.

Dave

[APS]

Thanks for the idea Dave. I found that thread but it is of no use unfortunately. That was about a copper washer on an angle Speedo drive on an overdrive box.
No such thing on my auto apparantly. Straight cable clamped on to the box. The parts manual identifies an oil seal and a couple of inner o rings.
I am not sure if it is as easy as it looks. But from what I can see I just need to remove the bolt securing the clamp and hopefully it will pull out.

I have also noticed this afternoon that the sump gasket is a little wet, even though I dried it with brake cleaner and cannot see how the leak from the Speedo drive can cause that. So I will be replacing the sump gasket too. Is there anything else I should be doing while in there ? is there a filter or anything I should do as a preventative maintenance ?
TIA Alan.

[APS]

I have now removed the gearbox sump and the speedo cable ahead of ordering the parts on Tuesday.

It looks like there is no seal in the speedo bearing housing unless it is very deep. The speedo bearing housing looks like it should just prise out but it appears fairly well stuck. Before I resort to using force to prise it out can anyone confirm please. I understand that there are couple of o rings on the bearing housing which I will also replace . TIA Alan

[APS]

In case anyone is interested.

It took a lot of effort and prising to get the Speedo bearing housing out. Eventually it came out and it appears to have been stuck in with a red gasket sealer. There was also no main seal for the speedo gear shaft so not surprising that it leaked. So I am hopeful that I have now cured the worse of my leaky bw65 gearbox.
The sump gasket was a little wet on the outer edge so I took the sump off to replace the gasket and whilst I was in there I changed the filter too. I got the filter from SNG Barrett, only £10.88 plus vat. At Rimmer's it is £48.50. Though tbh the old filter was quite clean but worth changing while doing this.
The other main suspect with these gearboxes, the selector shaft seemed quite dry. So I will fill it up tomorrow with fresh fluid and keep my fingers crossed.

[richardthestag]

The speedo drive and housing should have o-rings fitted.

Removing the drive and housing is not that tricky but access is tight, certainly was on BW35, recall that I had to drop the gearbox x-member in individual parts to get it past the exhaust downpipes.

Remove speedo cable, remove bolt and fork that secure the housing flange to the gearbox, refit the cable and give it a little tug. helps if rear wheel is off the ground to help the gear disengage from the drive else they are not usually that tricky, reassemble with new o-rings and bob is your mothers uncle

speedo.jpg

https://rimmerbros.com/Item--i-GRID005253

[APS]

Yes new o rings fitted and the seal nkc105a that was missing on my car, hence leak. Turned out not to be a difficult job other than a po had stuck the speedo pinion housing in with gasket sealant. Had no need to drop the gearbox cross member on the BW65, car on axle stands and 20 mins on my back under the car. First time I have done anything on an auto box so good learning experience just hope that I have no more leaks.

[Stag About Town]

This pdf on the BW65/66 from the Auto Transmission Service Group has a lot of info. Worth a download. John BW65-66.pdf