Re: Diff Needed!

From: Adrian
Category: Technical
Time: 01:28:04

Comments

Yeah, I can see how that g'box failure would be 'interesting'! I have heard that s/h autoboxes that have been left unused are prone to failure owing to the fluid degrading. This is partly why I'm suggesting a repair of your existing 'box.

The idea that an auto saps power is probably overstated. Working properly, the torque converter 'slips', but while it's in this state it's multiplying the torque output, so bar the inevitable mechanical losses in any system you're getting out what you put in even if the tacho seems to tell you different. This is different to a slipping clutch, which IS just wasting power. So first up are some tests on the torque converter to see if it's working properly..... if not; a new one, much the same as changing a clutch, altough you can get modified ones for various purposes. BTW, 'our' converters have an infinitely variable ratio between 2:1 and 1:1, so even if you only count that as 3 ratios, X 3 gears in the 'box proper = 9 forward speeds... cool! The gearbox itself has (I believe) two high pressure oil pumps in it; these of course do take power to run, just like a power steering pump, uprated oil pump, etc. The hydraulic pressure is controlled by the valves to operate the various clutches. So that's the other test: line pressure at various points in the operation of the 'box. This may show up that adjustments are required or repairs to one of the clutches or the valves is needed. These tests are made with the 'box in the car, after which you'll have a better idea of repair vs replace. I'd definately be thinking about the strength of the old 'box..... that rebuilt engine might just be the last straw!

Like I said, find out which taxi firm near you runs 'black cabs' (Austin FX4) 'cause lots of them had BW autos so the black cab firm will know the good recon places.

Good luck, if I lived closer you could borrow the 35 from my 'resting' MK1! Adrian.