rhansel Posted January 21, 2014 Posted January 21, 2014 Hello all. I'm new to this forum. Apologies if this topic has been covered to death before. I have just had my front diff insulator mount changed and now I have a clunk from the rear of the car whenever I drive off and when changing gears upwards. Clunk isnt so noticable when going down the gears. What stumps me is that I didnt have this noise before. Before I had he diff mount renewed, I had a clunk but only when going over bumps due to the badly failed front diff mount. I have crawled under the car when it is stationary and not running and can rotate the drive shaft about an inch or so and can hear a clunking coming from the diff (from the ring and pinion I assume). Is there something else I should consider looking at before I come to the conclusion that my ring and pinion need replacement. I cannot see how changing the front insulator diff mount would result in this noise from the diff. If I do need to get a replacement diff......does anyone know of a Zed shop that sells has these units reconditioned? There used to be a Zcar workshop in Underwood in Brisbane, but the owner Alan retired some years ago. Cheers. Quote
dat2kman Posted January 21, 2014 Posted January 21, 2014 Are you in Cairns or Brisbane? I have here in Brisb, some R180 cw&p's On slght accel/decell, ie on and off throttle, is it clunk clunk, f so that could be excess backlash, this requires the diff pulled apart, the teeth "blued" and a pattern of "wipe" will show, then the side plates and pinion will be adjusted, and pinion crush washers added or removed, to then take out that excess backlash. Thats a job for a shop. Steve at Diff and Gearbox Industies on Newmarket Rd Windsor, behind a Matilds servo can do this. If its a single clunk on upchange, as you release the clutch, ie applying engine torque through to diff, what is happening at the nose, or front , of diff, is the diff is trying to part company with the mount and visit you in the cabin. The rubber band strap, or chain, if fitted, on later models, stops this. Just cos you got under and jiggled, is not the test for a torn diff mount. It needs removing, 30+ years of grease and grime removed, and a close inspection, and replaced, or, the rubber between the top and bottom metal plates of the mount, and re-rubbered. This service is available ex Brisbane, i will require your old diff mount. Also, third thing, the rear moustache bar have been known to crack due to fatigue, rare, but can occur. Quote
rhansel Posted January 21, 2014 Author Posted January 21, 2014 Thanks for your replies dat2kman and dat240z. Re the arrestor strap, this is still in place. My front diff insulator mount is brand new as my old one was totally decayed. Is it worthwhile temporarily wedging something between the top of the diff insulator mount and/or front of the diff (like a small block of wood) and the underside of the body to restrict upward movement of front of diff that you mention just to see if that eliminates the clunking when changing gears. There is only ever one clunk.....one when driving off, one when going up at each gear change and putting torque on diff and if I pressing gas pedal firmly when in motion. It sounds like the system is taking up slack somewhere whenever I hit the gas pedal. If I try the wedge and the noise disappears, then I assume I will need to get a new arrestor strap to restrict upward movement of front of diff. I live in Cairns and there aren't many shops that will work on old Zeds as they are too old and most can't be bothered. Quote
Scoota G Posted January 21, 2014 Posted January 21, 2014 Check the tension on the nuts that attach the diff cover to the mustache bar. Quote
dat2kman Posted January 21, 2014 Posted January 21, 2014 When you said " renewed your diff mount" that could have maent, pulling it out, giving it a kerosene bath seeing the rubber is in there and re-installing. Good that you put in a new one! Go over all rear end nuts and bolts, tailshaft to pinion flange, halfshafts at inboard diff end, as well as outboard at stub flange. Nspect moustache bar, undo the two centre bolts/nuts, check under, refit. Drive it. Still there, try the timber wedge, but a brand new diff mount wont have let go! If still there, it will be excess backlash, you'll need a diff shop or a mechanic shop that is able to do diffs. Though backlash is there on both gas on/gas off, as will be lots of other things! Ask around the lcal guys who preps rally cars, a few have come from Cairns, someone will know which shop, head for them. Bottom shock mounts? Lower control arm bushes/mounts? Outer spindle pin nuts? Lots there! Quote
rhansel Posted January 21, 2014 Author Posted January 21, 2014 Hi all. Thanks for all your suggestions. I had another crawl under the zed and amazingly, the mechanic who fitted the new front insulator diff mount forgot to tighten up the nut in the centre which secures the mount. I've tightened it up and all the clunking when driving off and changing gears is gone. All back to normal. Obviously with the nut not done up properly, the mount was I gather letting the diff and shaft move up whenever torque was applied. I'm happy it was such a simple fix. Again, many thanks for all your suggestions. Cheers. Roy Quote
dat2kman Posted January 21, 2014 Posted January 21, 2014 Great mechanic!! Better throw a spanner over other nuts/bolts! Quote
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