Gear Box Out Again

After a couple of days, the gear box started popping out of 4th on the over-run.  It was also a little noisy, too.  I suspect the problem was how I fitted the transmission after replacing the broken gear – instead of assembling the entire transmission and then lifting it into the vehicle with a crane, I did it in sections by hand.  I think this allowed the primary pinion and main shaft to be slightly kinked as the back of the main shaft was unsupported.  With the loose fit of the bell housing on the flywheel housing, the pinion may have been at a slight offset and angle, causing bearing noise and the jumping out of 4th, like the worn spigot bush did when I first fitted the Tdi.

using input pinion as driftusing pinion for clutch alingnmentI spent today removing the whole transmission and replacing the main shaft bearings.  The selectors and top cover need refitting and then it will be ready for re-installation, with the standard rear bearing housing fitted to the transfer box to hold it all straight as it gets mated to the engine.  I have replaced the spigot bush, even though the existing one has only been fitted for 25,000 miles and was  still in good condition.  I used a spare pinion to drift the new bush in and then to align the clutch.

I spent last weekend replacing the 3.54 Salisbury diff with a 4.71 unit from a 109 axle, and it was much easier than the manuals suggest.  That seems, at the risk of jinxing myself again, to be working happily.  It’s a shame to lose the top end cruising speed and quietness, and also the fuel economy, but it does drive more nicely around town any on the hills and should prevent another gear box failure.  I’ll be posting a big write up on that once I have attached the photos to the script.

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