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Automatic Transmission Repairs in Scotland
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peter scott



Joined: 18 Dec 2007
Posts: 6216
Location: Edinburgh

PostPosted: Thu May 31, 2018 10:36 am    Post subject: Automatic Transmission Repairs in Scotland Reply with quote

A friend of mine has a Humber Super Snipe with a BW250M autobox that is slow to change up to top gear. He has done the following:

Transmission fluid in box (Castrol TQF) was about 25 years old and had covered 25,000 miles. After the above measurements, all fluid was drained off from gearbox and torque converter, and replaced with Comma AQF (total approx. 8 litres after priming the torque converter). The sump had been removed a few months earlier and the filter and sump cleaned, although there was relatively little residue. The old transmission fluid was darker than the new stuff, but smelled normal.

With the pressure gauge connected to the Direct Drive Clutch take-off point, we did a road test with my wife monitoring the pressure gauge. It remained at zero until about 18 to 20 mph when it rose quickly to about 60 psi. As the speed increased to around 27 mph, Direct Drive engaged with a slight jolt and the pressure increased to 80 psi and remained steady at that level. With foot off the accelerator and coasting down, the pressure remained high until about 12 to 15 mph, when it suddenly dropped to zero with a smooth gear change.

On a longer 90 mile trip with the new AQF transmission fluid, the gearbox seemed more responsive than previously (maybe the old transmission fluid had become more viscous over time). When warmed up, the transmission would change into Direct Drive quite readily at 22 to 24 mph under light to medium throttle, and without any hunting. As we found earlier, after first driving off, it does take a higher speed to make the first change into direct drive top, but thereafter is normal. I suspect this may be due to the rear pump taking more time to build up pressure as the car gets moving. Thereafter, the pressure does remain stable showing the main relief valve appears to be working correctly regulating the pressure.


But is now looking for a dependable specialist who knows about these boxes. Any suggestions?

Peter
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1939 SS Jaguar 2 litre saloon
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47Jag



Joined: 26 Jun 2008
Posts: 1470
Location: Bothwell, Scotland

PostPosted: Thu May 31, 2018 11:32 am    Post subject: Reply with quote

Peter,

What about Jamie Whatisname (I know you will know his name ) that used to be big in Jaguar Eccosse. He had a MK2 pickup? Drove a series 1 XJ V12. He has probably retired but his business may still survive.

Art
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peter scott



Joined: 18 Dec 2007
Posts: 6216
Location: Edinburgh

PostPosted: Thu May 31, 2018 12:05 pm    Post subject: Reply with quote

Thanks Art.

Jamie Gibbon.

Jaguar Specialist: Jamie @ Gibbon & Wilson Garscube Mill Killermont Bridge Bearsden G61 1QR 0141 943 1333.

I'll pas it on.

Peter
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