Flash Posted September 17 Share Posted September 17 Hey All, I'm in need of some guidance on a new issue with my '66 Tang. All of a sudden the C4 tranny has started making a rumbling sound when in gear. It sounds a bit like an exhaust resonating. Noise goes away when in park but comes back when I select any of the forward or reverse gears. Fluid is clean and is at the correct level. I'm not sure what's causing the issue, but it sounds bloody expensive. Any help would be appreciated. Ta in advance. Quote Link to comment Share on other sites More sharing options...
Lord Gruntfuttock Posted September 17 Share Posted September 17 How's the fluid. Checked level on dipstick with engine warm and in park? Colour? Burnt smell? [Edit] sorry just read properly. If fluid looks good I've got nothing... Quote Link to comment Share on other sites More sharing options...
Lord Gruntfuttock Posted September 17 Share Posted September 17 They're a strong tranny. My only failure was when the torque converter fins fell off and I lost drive (burnouts to blame prob). Still running same trans but I've put alloy sump and thick silicone gasket on after suffering leaks and have replaced the filter, lower pickup too with deeper sump). There were a few flakes in the sump but I've chosen to ignore them... Quote Link to comment Share on other sites More sharing options...
Unclejake Posted September 17 Share Posted September 17 Do you hear the sound when in gear but stationary, or only when moving? Quote Link to comment Share on other sites More sharing options...
RUNAMUCK Posted September 17 Share Posted September 17 How are the mounts? Soggy/blown mounts can cause things to lay over/rub when in gear which transmits vibration into the car. 1 1 Quote Link to comment Share on other sites More sharing options...
Flash Posted September 17 Author Share Posted September 17 2 hours ago, Unclejake said: Do you hear the sound when in gear but stationary, or only when moving? Thanks mate, yep the sound is there when in gear but stationary and also when moving. Quote Link to comment Share on other sites More sharing options...
Flash Posted September 17 Author Share Posted September 17 2 hours ago, RUNAMUCK said: How are the mounts? Soggy/blown mounts can cause things to lay over/rub when in gear which transmits vibration into the car. Thanks, good suggestion. I'll take a look at the mounts tomorrow. 1 Quote Link to comment Share on other sites More sharing options...
Flash Posted September 17 Author Share Posted September 17 3 hours ago, Lord Gruntfuttock said: How's the fluid. Checked level on dipstick with engine warm and in park? Colour? Burnt smell? [Edit] sorry just read properly. If fluid looks good I've got nothing... Yep, fluid is clean. No burning smell at all. Driving the car it shifts nice and smoothly. Torque convertor is a Hughes Performance 2000RPM that was installed in 2013 and has done less than 8,000 miles. Between myself and the previous owner the car has never been driven in anger. 1 Quote Link to comment Share on other sites More sharing options...
Unclejake Posted September 17 Share Posted September 17 25 minutes ago, Flash said: Thanks mate, yep the sound is there when in gear but stationary and also when moving. Oh dear. At least that eliminates everything behind the output shaft.. If there's an inspection plate on the bellhousing I'd check for a loose flexplate/tourqe convertor (if the gearbox mounts seem OK)... but apart from that I am out of ideas. Best of luck Flash. Hopefully it's nothing too serious 2 Quote Link to comment Share on other sites More sharing options...
RUNAMUCK Posted September 17 Share Posted September 17 Mounts includes the engine mounts too. 2 Quote Link to comment Share on other sites More sharing options...
Flash Posted September 17 Author Share Posted September 17 4 minutes ago, RUNAMUCK said: Mounts includes the engine mounts too. Thanks, I'll check them out too. Quote Link to comment Share on other sites More sharing options...
Flash Posted September 17 Author Share Posted September 17 26 minutes ago, Unclejake said: Oh dear. At least that eliminates everything behind the output shaft.. If there's an inspection plate on the bellhousing I'd check for a loose flexplate/tourqe convertor (if the gearbox mounts seem OK)... but apart from that I am out of ideas. Best of luck Flash. Hopefully it's nothing too serious From memory the only inspection point without removing the tranny is by removing the starter motor. I had the starter out earlier this year and took this candid shot at the time: If the mounts aren't the issue maybe I should pull the starter for another look. Quote Link to comment Share on other sites More sharing options...
Unclejake Posted September 17 Share Posted September 17 It's interesting that the noise is present under both reverse and forward load. It could be as simple as a broken exhaust mount. Probably worth someone under the vehicle when it's running and in gear before you pull too much apart. In related news: I have spent weeks (off and on) trying to find a knocking exhaust over bumps in one of my Land Cruisers. I could have sworn the exhaust was hitting the gearbox. The sound was absolutely coming up from the transmission tunnel.... but strangely stopped when I cleaned the inside of the windscreen last week..... and it fell out onto the bonnet. 1 6 1 Quote Link to comment Share on other sites More sharing options...
Flash Posted September 17 Author Share Posted September 17 5 minutes ago, Unclejake said: It's interesting that the noise is present under both reverse and forward load. It could be as simple as a broken exhaust mount. Probably worth someone under the vehicle when it's running and in gear before you pull too much apart. In related news: I have spent weeks (off and on) trying to find a knocking exhaust over bumps in one of my Land Cruisers. I could have sworn the exhaust was hitting the gearbox. The sound was absolutely coming up from the transmission tunnel.... but strangely stopped when I cleaned the inside of the windscreen last week..... and it fell out onto the bonnet. Funny you should mention the exhaust. When I first heard the noise I thought something had broken loose inside the LHS muffler as it sounded exactly like that, a bit of a tinny sounding rattle. I'll have a good check underneath tomorrow. Quote Link to comment Share on other sites More sharing options...
Kiwibirdman Posted September 17 Share Posted September 17 Check the torque converter bolts. The other one, harder to do is the flexplate to crank bolts. If you get to that point, check the flexplate for cracks. Unlikely to be the box if it still drives OK. 2 Quote Link to comment Share on other sites More sharing options...
RUNAMUCK Posted September 17 Share Posted September 17 Loose torque converter bolts usually make a clattering noise. 1 Quote Link to comment Share on other sites More sharing options...
Flash Posted September 17 Author Share Posted September 17 Thanks fellas, I'll check them out. Might be worthwhile me pulling the box while I'm about it as I've got a weeping rear main seal that I've been ignoring for a while. Quote Link to comment Share on other sites More sharing options...
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