Nick
Posted a lot
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Mar 30, 2006 21:32:26 GMT
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some quick advice needed, in the supra, i'm having some nasty moments with the diff locking up,
now its got an LSD and I'm hoping to keep it that way, but when ive been having a spirited drive and coming down the gears always coming into 2nd gear the diff seems to lock up which has led to a few "uh oh " moments... my heeling and toeing is pretty spot on so its not related to that i don't think?
so is it maybe just a case of changing the oil and all should be well or is it signs of worse things to come ie ? replacement lsd
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idea stolen from rattely eddie.
this weeks car count "5"
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Mar 30, 2006 21:48:57 GMT
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Jeezus, sounds bloody lethal!
I don't know much about LSD's but anything other than oil changes and outright swaps is probaly not a DIY proposition. Chenge the oil and see what happens.
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1972 Fiat 130 1985 Talbot Alpine 1974 Lancia Beta Saloon 1975 + 1986 Mazda 929 Koop + Wagon 1982 Fiat Argenta 2.0 iniezione elettronica 1977 Toyota Carina TA14 BEST CAR EVER!!!!!!!! 1979 Datsun B310 Sunny 4-dr 1984 Audi 200 Quattro Turbo 1983 Honda Accord 1.6 DX GONE1989 Alfa 75 2.0 TS Mr T says: TREAT YO MOTHER RIGHT!
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Mar 30, 2006 21:54:07 GMT
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Chances are the diff oil has never been changed so its worth draining it and having a look when you do. But I don't think it will be oil related. If its locking when you are putting it into second but not locking when you are in neutral then I don't think its a diff problem as such. Jack it up and try rotating it forward and backward make sure there is nothing that sounds unusual. Check and see how tight the diff is. It sounds more like the engine breaking is locking the back wheels up rather than anything else.
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Nick
Posted a lot
Posts: 2,483
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Mar 30, 2006 21:56:58 GMT
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it is pretty lethal at the mo, just wierd never had a problem like this when i had my bmw with either the lsd or the welded diff, i was expecting it to be much more civilised and so far it keeps trying to kill me.
yeh thats why i put about the heeling and toeing cos I'm sure it cant be the engine braking locking them up i dunno just never had a car that acts like this before.
anyway i'll have a looksie at the diff and check out for wierd clonks and stuff;)
thanks
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idea stolen from rattely eddie.
this weeks car count "5"
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Diff locking upBenzBoy
@benzboy
Club Retro Rides Member 7
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Mar 30, 2006 22:02:57 GMT
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When I used to drive a Merc Sprinter the front wheels used to lock up under heavy engine breaking . Absolutely fugg-all to do with this post though... Sounds a bit scary tbh! Changing the oil might help matters, and it's relatively cheap if it works.
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Mar 30, 2006 22:05:58 GMT
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You know what your preload is on the diff?
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Nick
Posted a lot
Posts: 2,483
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Mar 30, 2006 22:11:52 GMT
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nope ive only had the car a week or so, and apart from rust hunting done nothing even remotely close to checking the diffpreload
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idea stolen from rattely eddie.
this weeks car count "5"
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Mar 30, 2006 22:16:41 GMT
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On my bloke front wheels drive racer, when you go full lock at slow speeds it cluncks as if a outer cv joint has gone.
Now i don't know if this is the same as a rear wheels drive car but it just a thought maybe, and his a preload of 120 lbs.
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The preload shouldnt make a big difference to the diff locking problem. When I rebuilt the diff on my MK1 escort I set it really tight so it is almost locked and the only way to get it to lock is by heavy engine braking.
Like I said before if it doesnt lock in neutral under braking then it probably wont be a mechanical problem. Unless for some reason when it is ramping up its causing it to lock. But jacking it up and checking it out is your first step.
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Anyone got any links to a good idiots guide to LSD’s? I mean how they work. I have never had one, except the one which is supposedly in my truck, and that is definitely an unlimited slip effort. I have not the foggiest how they work.
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1972 Fiat 130 1985 Talbot Alpine 1974 Lancia Beta Saloon 1975 + 1986 Mazda 929 Koop + Wagon 1982 Fiat Argenta 2.0 iniezione elettronica 1977 Toyota Carina TA14 BEST CAR EVER!!!!!!!! 1979 Datsun B310 Sunny 4-dr 1984 Audi 200 Quattro Turbo 1983 Honda Accord 1.6 DX GONE1989 Alfa 75 2.0 TS Mr T says: TREAT YO MOTHER RIGHT!
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Is the diff unusually noisy.? It could possibly be the pinion bearing breaking up, but I would have expected you to have complained of a whining noise.
I think it might just be engine braking locking the back wheels. When I got my first RWD car I had the same thing happen to me, in spite of heel & toe. It simply required adapting my driving style when using the Asconas. Engine braking seems to unsetle a RWD car, at least in my experience. I find that I can not drive RWD as quickly and as confidently FWD though :-( I guess it's just what I cut my teeth on.
LSDs require special oil, but I'm not sure this would be causing the problem. Worth giving the diff an oil change as a service point anyway, especially if you indulge in a bit of dorifto ;-)
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Nick
Posted a lot
Posts: 2,483
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Mar 31, 2006 10:01:43 GMT
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diff isnt unusually noisy or anything. hope it isnt anything like the pinion bearing breaking up..that wouldnt be too helpful
thing is ive driven some cars with quite uprated LSD's that are a lot more "harsh" than the one in the car and never have the problem of the rears locking up unintentionally.
Going to stick in some of this castrol LSD oil a friend of mine has and see if its anything oil related.
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idea stolen from rattely eddie.
this weeks car count "5"
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Mar 31, 2006 18:56:43 GMT
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With a plate LSD your diff cage still has your 4 spider gears ( 2 side gears and 2 planets). But instead of the planet gears being fixed in a solid cage, the cage is in two halves. The small pinion shaft that the planet gears run on now sits in two V shapes one in either side cage. Under heavy accelaration or braking the shaft will actually run up the sides of the ramp opening the cage and putting more pressure on the clutch plates and locking the diff. The angle of the ramp varies how much and fast the diff locks. A one way LSD will only lock the diff in accelaration it wont lock it under braking. A 1.5 way LSD will lock it more during accelaration than it will under braking. A 2 way diff gives the same amount of lock accel and braking. You cant do much about the ramp angles at home so all you can do is set the preload.
As far as I know, proper LSD oils such as castrol LS have additives to aid slipping of the clutch plates making them more useable for normal road use but the diff wont be as tight. Normal diff oils don't have these additives and as a result if you put them into an LSD you end up with a much tighter diff. Atlas axles (2.8 capris etc..) had a fairly open diff and it was recommended running a standard hypoid diff oil to tighten them up.
I was recommended to run a semi synthetic for my atlas axle after I rebuilt it and have been happy with that. Its cheaper than castrol LS which was around £25 for 5 litres last time I bought it but your clutch plates will wear out faster.
I presume your celica is a plate type diff I don't think toyota used a viscous diff until the mk3 celica. Viscous diffs will normally be a lot more open than an LSD. ATB diffs use gears to create friction to lock the diffs one problem with these is if a wheel lifts off the ground it will spin and you loose traction.
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Last Edit: Mar 31, 2006 18:58:40 GMT by PhoenixC
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Nick
Posted a lot
Posts: 2,483
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Mar 31, 2006 20:44:09 GMT
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yeah its a plate diff,
not got round to changing the oil yet,
took the car out tonight for some practice on some local circular private racetracks, and the diff acts very wierdly. not predictable and pretty sketchy at times. seems to keep locking and unlocking and makes the car squirm and act odd, when i am trying to maintain a perfect plateau of sidewaysness.
thanks for all that info pheonix C i didnt know all that about oil,s
familiar with 1way 1.5way 2way and 3 way;)
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idea stolen from rattely eddie.
this weeks car count "5"
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