After a relatively quiet day yesterday, it was down to business today. Whilst we were reasonably confident the torque converter had failed, it was vital to open up the gearbox and have a check. After a fight with a couple of corroded bolts, those nearest the front of the 'box in direct lime of salt sprays, the 'box came apart.
The good news is that the clutches are absolutely fine after 140,000 miles and on the original oil
Here's a B Clutch (the one that works hard) lining:
The F Brake, which can wear, is also fine. However, looking at the top of the oil filter, the picture is not quite so rosy. The grey stuff is fine metallic powder
The bottom of the 'box contains more of this deposit and a couple of lumps of unidentified metal.
next up for inspection was the oil pump and it was found to be rather worn.
Here's a few shots of it's components showing the scoring. The oil pump gears show signs of fretting and "picking up"
Note the scoring at the green arrowhead and also the condition of 140,000 mile old oil. Not bad at all!
Here's a shot of the pump gears:
Note the damage at the heads of the green arrows.
So what happened? The best we can think is the stator sprag or lockup clutch in the TC began to break up and shed some metal. This found its way into the TC tail bearing and then into the oil pump. The debris visible on the oil filter may be remnants of this or bits of the TC tail bearing. Whatever and wherever it came from, it has wrecked the oil pump and this must be replaced. What we do know is that none of it originated in the gearbox proper
I called for some quotes for spares prices and had a most interesting conversation with the parts man.
I asked for the cost of a new oil pump and torque converter and he said:
"Ahh, I bet you pulled the converter off and found a bearing welded to its neck.."
"Yes, precisely!"
"It's how they all go.."
He went on to say that nobody quite knows why. ZF reckon it's oil contamination and others say it's overheating. In truth the jury is out...
The cost of an oil pump, which is only supplied as a complete unit, is £288 whilst the torque converter is a more reasonable £99 + carriage for a remanufactured item. It is rebuilt by a firm in Glasgow. With consumables on top of that, (filter, seals, transmission cooler) the old wallet is going to take a battering
Thinking on, I wonder if these reports of the odd lock-up and lurch is the first sign of the TC tail bearing going and momentarily seizing?
My own V6 needs a little fettling this week. She's clearly jealous of another V6 in her place and has complained by springing a minor LHM leak from her rear electrovalve
To round off the day today, I briefly saw Gareth in his Activa. he was en-route for the Milton Keynes IKEA and popped in for a quick Lexia session
I really got a quick taste today of what it might be like if I started up my own small specialist business
yes your right of course, i thought i was going a bit mad so since it was raining and there is naff all on telly i went back out into the garage, pulled the box out and stripped it again, here is the bearing, you can see it on the oil pump housing/ stator shaft mount.
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