BW65 /66 gearbox in XJ6 Series 2

The 66 is the strenghtened version of the 65, but the throttle cam and valve body should be interchangeable, the only changes I know are the input shaft is stronger, the torque converter is slightly different, the sump is deeper and the pickup has a spacer to reach the deeper bottom. It shouldn’t be a problem.

My biggest problem at that moment is a cold, and a lot of rain here.
I already have a gauge inside the car and will name the pressures next time very exactly. To be honest, I misunderstood the ferrule, I thought it is a fixed part just to the cable and not a mark to the complete system “transmission”.
It is also clear now, that the pressure difference from 750 to 1200rpm is the important thing, and not to be in the tolerances somehow.
Front clutch or rear band: In D/1 and 1 is the same slip effect, so I exluded the rear band and the oneway clutch.
But a further interesting test will be a little forced reverse travel with just rear band and clutch engaged.
A last idea is the check valve in the front clutch housing. If there would be a leakage, would it be possible, that the gauge will not recognize it because of small tubes and long ways to the clutch behind the measuring point?
Let me say it in German: Am besten: Testen
Thanks to David, Frank an Tony for your patience and breaking your heads.

[quote=“Werewolfgang, post:22, topic:442067, full:true”]
…Impeccable logic all around, Wolfgang - when testing; hold the car with the brake and push the pedal. That should load the clutches and bands, causing slip - if there is one.

There certainly are vast possibilities of leaks and blockages within the valve body to cause the oddest symptoms - and difficult to assess. If you still have the old box; you may, at one stage, consider replacing the valve body with the one from the old box? The problem, harsh shifting, with the old box may just have been a cable adjustment issue?

As an aside; the psi readings reflect line pressures - the actual pressure exerted on bands and clutches is a function of psi times square area of servo pistons.

xj6 85 Sov Europe (UK/NZ)

[quote=“davidsxj6, post:20, topic:442067, full:true”]

I said this exactly…

Adding that the three inputs are interdependent, David - and the pressures are always ‘adequate’ to ensure firm clutch and band ‘lock-up’. And the valve body works as it should…:slight_smile:

xj6 85 Sov Europe (UK/NZ)

Dear David Frank and Tony
Thanks for your help, after a couple of weeks doing other projects I restarted it again and got good results with waiting and adjusting.
A friend built a 8 channel voltage meter for my Notebook for me and this was wonderful. In China we got digital pressure sensors for small money and with this sensor I made road tests and the TV cable adjustment. The slip when strong accelerating from standing is gone. Either the oil change or thr TV cable adjustment was working, maybe together. But there was still a noise in first gear with strong acceleration and an engine flare-up in kick-down from 3 to 2 over 80km/h (up to 75 kmh kickdown was normal). So I decided to adjust the bands, although the transmission was professionally rebuilt. They were much to loose.
Now it drives very fine, waiting for some more tests and drives. I would never expect the the TV cable adjustment has such an effect.
The voltmeter is also a very helpful tool for road tests

I used three channels for fixed marker lines at 4,2bar 5,3bar and 8,1 bar for the adjustment. Very interesting effect the increasing pressure up to 15 bar with strong acceleration from standing still. Next version will include engine revs and car speed.
Thanks again for your very helpful inputs.

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It’s absolutely essential for shift points and smoothness, Wolfgang - and it is veeery sensitive. But slipping is generally associated with band adjustments…


xj6 85 Sov Europe UK/NZ)