abarth_1200 Posted September 29, 2014 Share Posted September 29, 2014 Hi guys so got my car back together and thought there was a little too much resistance. If I lift it up and rotate the rear wheels forwards the front wheels rotate backwards. Don't get my issue confused with left and right opposite rotation it front and rear opposite now. Do I have to dismantle and swap one of the diffs round Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
abarth_1200 Posted September 29, 2014 Author Share Posted September 29, 2014 https://vimeo.com/107470953 Quick video, tell me I'm not being stupid and they all do this with fresh oil in diffs Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
mattr Posted September 29, 2014 Share Posted September 29, 2014 One of the diffs/diff cases is in upside down, your ring gear is on the wrong side. Quote Link to comment Share on other sites More sharing options...
abarth_1200 Posted September 29, 2014 Author Share Posted September 29, 2014 Which one, how do I tell. No instruction in my manual about which way to fit them. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
.AJ. Posted September 29, 2014 Share Posted September 29, 2014 (edited) Flip the one which goes the wrong way Edited September 29, 2014 by .AJ. Quote Link to comment Share on other sites More sharing options...
Smoothybb Posted September 29, 2014 Share Posted September 29, 2014 As above, probably the one that's not going the way you want it to....... Quote Link to comment Share on other sites More sharing options...
abarth_1200 Posted September 29, 2014 Author Share Posted September 29, 2014 I don't know how to work that out, lift the front push the rear wheels forward, the front goes backwards (sounds like I need to swap the front), it's not that easy. Now I lift the rear and push the car forward, the rear wheels turn backwards. (Now it's rear I need to swap apparently) So by that answer they are both the wrong way round. My brain is going to explode with this headache Quote Link to comment Share on other sites More sharing options...
Smoothybb Posted September 29, 2014 Share Posted September 29, 2014 (edited) Few pulls on the engine will tell you which way that drives the spur. Turn the spur the same way and you should be able to tell which set are trying to drive backwards. I did it once but managed to fluke both the wrong way. Fire up the engine and.......... wait a minute why's it accelerating at high speed backwards. Thought I'd somehow reversed the engine (possible). Edited September 29, 2014 by Smoothybb Quote Link to comment Share on other sites More sharing options...
abarth_1200 Posted September 29, 2014 Author Share Posted September 29, 2014 Alright guys, got it sorted, front was the wrong way. Surprised I haven't already read problems like this before, I can't be first noob to tear my car down to fill the diffs and put them in backwards! Was also surprised to see oil in the diffs already, was second hand but wouldn't have thought the original owner would have done that mod. Thanks for your help. Quote Link to comment Share on other sites More sharing options...
atom3624 Posted September 29, 2014 Share Posted September 29, 2014 Happened to me 14 years ago with my first E-Maxx. Thought I'd roll it and see how free-running this MT with bearings everywhere would be, and was surprised to see the wheels going in opposite directions!! Al. Quote Link to comment Share on other sites More sharing options...
Veed79 Posted September 29, 2014 Share Posted September 29, 2014 Yep your not the only one, first time I stripped my front diff down to replace the gears I put diff in backwards all back together went out over the park and all four wheels just spun on the gravel took me a while to realise what I'd done. Quote Link to comment Share on other sites More sharing options...
Pistonhead Posted September 29, 2014 Share Posted September 29, 2014 Happened to me when i did the diffs on my Hyper 7, except i just fired the engine up and it went nowhere lol Quote Link to comment Share on other sites More sharing options...
Nitroholic Posted September 30, 2014 Share Posted September 30, 2014 Some cars have diff cases that are shaped ...and you cannot put the diff in the wrong way ( HPI Savage for example ) Others have a lump of plastic on one side of the case which stops you putting the diff in the wrong way round ( Hyper 7 ) On others, you can put it in the wrong way! My old TT EB4 for example. If in doubt, mark the diff housing with a blob of paint, or mark it in some way so you know that side is where the ring gear goes. Quote Link to comment Share on other sites More sharing options...
RadioFish Posted September 30, 2014 Share Posted September 30, 2014 My ansmann sc4 diffs are a bit poo I lift the car n all four wheels turn exactly the same unlike my tomahawk someone help Quote Link to comment Share on other sites More sharing options...
abarth_1200 Posted September 30, 2014 Author Share Posted September 30, 2014 Well i managed to put my Hyper 7 diffs in the wrong way round, I did see a bit of plastic protruding into the casing but it still went in either way. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Rory Posted October 5, 2014 Share Posted October 5, 2014 I did this with my hyper ST one time, it was on the ground revving away with the back and front wanting to pull each other apart. OOPS! Quote Link to comment Share on other sites More sharing options...
subaru-swift Posted October 7, 2014 Share Posted October 7, 2014 I did it a few days back on the rear diff on my mini inferno, when I changed the front & back to Ball Differentials.it did made me laugh after 25 mins of thinking & trying things to make it right, one more lesson learnt now. but only a few thousand more to learn about this dark RC art of repairing \ upgrading etc etc. . Quote Link to comment Share on other sites More sharing options...
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