Monday, 8 August 2011

Changing gearbox

During my recent trip to the Alps the gearbox in the DHC developed some nasty noises. Especially when in neutral and/or hot it rattled away quite happily, indicating something with the bearings wasn’t as it should be. As the car will be used for Club Triumphs 10 Countries Run in a month’s time, a gear box swap seemed like a good idea. And while going through my spare parts in search of a better ‘box, I remembered that when I prepared the car for the 2007 edition of the 10CR I made a mental note to swap the gearbox in the not too distant future. Clearly forgot that when I restored the car ! And I found a reasonable box to use. As it hasn’t done more than 100.000 kilometres and has no noticeable play on the input shaft it should be OK.
So last Friday evening I parked the car in the workshop and started the preparations for the gearbox swap. This meant removal of the prop shaft, exhaust system, starter motor and clutch slave cylinder, and disconnecting the speedo cable ...




Also drained the oil from the ”old” gearbox. I had expected some grindings in the oil or on the drain plug, but there was absolutely none.

And on Saturday I returned with some extra hands to take the ‘box from the car, which went very smoothly. But the removal of the heat shield from the starter motor should have been a warning, it just didn’t want to come of the starter motor ...


With the old ‘box from the car it was time to inspect it. And indeed the input shaft had a fair amount of play. So we carried on and swapped the gear change extension over to the “new” box ...


and clutch release mechanism. I had a few reservations about fitting the last one, as it can sometimes be a real pain to put it back inside the bell housing. But I needn’t have worried it slipped in quite nicely at the first attempt ...


After that it was just a matter of putting the gearbox back under the car. But we needed three attempts before the gearbox slipped in place. Seems like they get heavier every year!
After lunch we returned to the car to bolt everything back in place. All went pretty smooth till we reached the exhaust, the manifold slipped in place quite nicely, only had to remove the strut brace for that. But when fitting the bolts Murphy paid us a visit. The least accessible one (lower rear) refused point blank to go in. Took me a very frustrating half hour to get it in place.


After that the rest of the exhaust system and the prop shaft went in without a problem. I should have gone home at that stage but I promised Robbie that I only needed his workshop for one day. On the other hand I only had the gear lever to put back. Sadly Murphy hadn’t gone home, so the lever, or more precise the anti rattle spring inside it put up quite a fight. But half an hour and lots of swearing later it slipped in as it should. Time to put the car back in the shed and head for home and enjoy a well deserved beer. Driving the very short stretch from the workshop to the shed revealed that the gear change was rather crappy, much worse than the old box. But at that moment I couldn’t care much!

So on Sunday I took ‘t Kreng for a short spin just for fun, after which she swapped places in the shed with the DHC. When setting of in the DHC the gear change indeed wasn’t very good, but not as bad as it had seemed the previous day. What should you expect from a box that has been lying in the corner of a shed for 5 years? And while driving along it gradually improved. Still not brilliant, but at least as good as the old ‘box, and with better bearings, so it should be OK for the 10CR. Plan is to drive the car as much as possible in the next few weeks to flush the box and renew the oil shortly before the 10CR. See how it all develops.

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