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Static gearbox test
Posted: Mon Oct 07, 2024 10:54 am
by diz
My car is off the road and before removing the engine for repair I would like to check the clutch and gearbox by running it in each gear. In theory I could run it while jacked up on axel stands, but, does anyone do this? and any tips on doing it safely?
Re: Static gearbox test
Posted: Mon Oct 07, 2024 11:09 am
by Peter Laidler
Good thought Diz but the problem doing a on-the-axle-stands test like that, is that the gearbox and importantly, the clutch, is not loaded. It is free-running (it's not really, but it's a good enough explanation for these purposes.....) There is no weight or drag or friction etc etc on the running gear. You can change up and down the box until the cows come home. Here's what I'd do if I was you.......
What about going to an MoT place or any small garage with a set of rollers. Put them in neutral, drop the front wheels on them and then drive the car. You ain't goin' nowhere but that will be a true (?) test of what's right in the drive train of your car. Mind you, it'll also tell you what is wrong with the drive train too.
Always eager to be corrected by the experts of course so don't hold back.....
Re: Static gearbox test
Posted: Mon Oct 07, 2024 11:46 am
by Spider
You can do that but as Peter suggests, it will only reveal limited issues, though, I would suggest doing it all the same. You may need to put a jack under the RH side ball joint nut and lift the arm a bit so the shaft doesn't rub in the subframe.
Another test, best done with warmed up oil though, wheels on the ground, is to idle the engine, leave your foot off the clutch and try and engage all gears, just briefly. If you just simply can't get any gear, but hear the engine loading up a little, that's good, if you get any grinding, then you likely have a worn baulk ring, weak synchro springs or other issues there to resolve.
While these checks may show some issues, the only way to really check it is to strip it.
Re: Static gearbox test
Posted: Mon Oct 07, 2024 4:44 pm
by diz
Thank you both. I don’t fancy the added compilation of trailering the car to an MOT station so will try the tests you have suggested at home. The gearbox is freshly rebuilt so if there are any gremlins I’d like to know before removing the engine (again!)