KevinM Posted May 10, 2015 Report Share Posted May 10, 2015 My Tr4a has the classic thump in the drive train from under the drivers seat. It will be welded up soon. I am also wondering about the diff itself. Does anyone know how much slack there should be in the diff? I have attached a picture with a peg attached to a spoke. It was taken with the wheel jacked off the ground, in first gear with the opposite wheel on the ground. The two images should the movement one way and then the other. Is there any way of determining the condition of the diff? I don't want to replace it if it is in good condition but don't want to put it back on if it needs removing anyway to do the welding. I have fitted CV jointed drive shafts so there is no slack here. Quote Link to post Share on other sites
Paul Harvey Posted May 10, 2015 Report Share Posted May 10, 2015 there are lots of places you get drive train slack but welding them all up affects the handling Quote Link to post Share on other sites
RogerH Posted May 10, 2015 Report Share Posted May 10, 2015 Hi Kevin, there are six places where slack can happen and then there is the diff. Propshaft - for/aft UJ's and the spline. Check these out. There should be no slack here. Drive shafts - inner/outer UJ's and the spline. Check these out. There should be no slack here. Diff - if you hold the front input flange and turn to/fro an output flange there will be some slack (you may need to hold the other flange still). I haven't got my WSM with me but there may be an angular dimension for good/bad. Roger Quote Link to post Share on other sites
KevinM Posted May 14, 2015 Author Report Share Posted May 14, 2015 Does anyone know how much movement (slack) in the diff is considered "ok"? Quote Link to post Share on other sites
stillp Posted May 14, 2015 Report Share Posted May 14, 2015 My 4A diff was greatly improved today by Mike Papworth. There was a bit of play in one of the output shafts, but he thought it would be OK. Mike said that about 5 thou play was OK, and mine was around double that, but would be alright for a low annual mileage.However, when he stripped it, the keyway was badly chewed up, such that the key was loose in the keyway. He had to scrap that one. The reason I removed the diff was an oil leak - hardly surprising, as the seal on that side had completely disintegrated. Quote Link to post Share on other sites
KevinM Posted May 14, 2015 Author Report Share Posted May 14, 2015 Hi StillP, do you know how much angular play there was? Quote Link to post Share on other sites
stillp Posted May 15, 2015 Report Share Posted May 15, 2015 Didn't measure it, sorry. It was about 10 thou of movement, with the 'inner works' of the diff held static. Quote Link to post Share on other sites
stillp Posted May 15, 2015 Report Share Posted May 15, 2015 Kevin, what part of the country are you? I'd have thought yours was OK, from your photos, but I'm not an expert. Quote Link to post Share on other sites
KevinM Posted May 17, 2015 Author Report Share Posted May 17, 2015 South Lincs Quote Link to post Share on other sites
stillp Posted May 17, 2015 Report Share Posted May 17, 2015 If you're worried, then while your diff is out it wouldn't hurt to take it to a specialist and get an expert opinion. I took mine to Mike Papworth in Coventry thinking it just had an oil leak, but he found a couple of other problems, and fixed them at a very reasonable price. Quote Link to post Share on other sites
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