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Post by 998automan on Sept 18, 2014 19:25:03 GMT
Hi, first time on the forum looking for help on the following: My 998 is slipping between 3rd & 4th gear especially when under load, any ideas on how to cure or is it an engine out job? The box was re-built 2 years ago and has been treated with care ever since (Millers 20/50 oil & 500 mile oil changes). Works well otherwise but has always been a bit noisy (clunky) when changing down, any ideas much appreciated!!
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Post by jockduck on Sept 20, 2014 1:53:10 GMT
Hi, when you say slipping between 3-4 do you mean "flaring" the engine revs up before 4th engages? Its a fairly normal complaint on early boxes particularly the first few changes when cold, does it improve with a warm engine? Later g/boxes had better oil supply to the top/reverse clutch so should be less affected. Ultimately the top gear clutch will get damaged if the slipping is bad. Did the box flare from the rebuild or is it a developing problem? Otto(68 minimatic) has flared cold since its rebuild 30,000 miles ago but is still good warmed up, a clunky downshift again is fairly normal assuming its not wheel locking! Jock
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Post by 998automan on Sept 20, 2014 18:44:05 GMT
Hi Jock. Thanks, yes `flaring` is a good way to describe it with the revs rising exactly as you describe. It did it both before & after the rebuild (but not so much after!) the company that did the rebuild have said that this is sometimes due to `glazing` of the plates due to lack of use or when the car is not driven particularly hard. It does improve when the engine is hotter so it sounds like I could be worrying about nothing... The clunky changes don`t affect the drivability at all, previously I had a 1993 auto that had a much smoother box all round and from what you say the later ones were improved so perhaps it is unfair to compare them. I have also been speaking to another transmission specialist who have told me that it could be down to my choice of oil. They have said that on a car of my age (1987) it should be running on 10/40 not 20/50 as this will damage the clutches, is this something you agree with? There don`t seem to be many mineral based 10/40`s around so I guess I would be looking at a semi synthetic? As always any recommendations massively welcome! Thanks again Mike.
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Post by jockduck on Sept 21, 2014 1:02:56 GMT
Hi, Oil is a tricky choice, I think a 10/40 would help in your case and was probably the recommended oil back in 1987, Otto has an original sticker on the rocker cover recommending Castrolite which was a 10/30! I use a 20/50 mainly to look after the engine in the Australian summer and put up with the gearbox until it warms up. Oils for modern cars are not what an A series with autobox needs, the latest oil don't have enough zinc and phosphorous to look after our flat tappets and to get around that they put in friction modifiers which will ruin the clutches and bands of the 'box, a lot of motorcycles use the same oil in the engine and transmission and there are some very specific oils in the market place for them but they are generally very expensive. I use Castrol GTX which is sold as being appropriate for "older cars" the oil to stay away from is the stuff intended for multivalve catalic converted engines, There are a lot of 10/40 diesel engine oils that would be suitable again the older type for non cat engines. I don't think I have heard of anyone on this forum advocating semi of full synthetic, my opinion is its a scam by the oil companies to get us to spend more money, why are synthetics significantly cheaper in the USA than the rest of the world? Jock
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Post by 998automan on Sept 21, 2014 17:57:46 GMT
Hi Jock, really appreciate your advice on this. Obviously it is a much debated subject! Will try the 10/40 route and let you know if anything improves. The good thing is I now know that I won`t be doing it any harm! Am I right in thinking that it will take 2 or 3 oil changes to fully swap the oil due to what gets left in the torque converter? Thanks Mike.
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Post by jockduck on Sept 21, 2014 23:18:13 GMT
Hi, Frankly I would not worry about multiple oil changes, jack the car up a little on the left side and leave the sump plug out overnight(there are lots of weirs and ridges inside the sump) There are two drain plugs on the torque converter but I strongly advise against trying to remove them. Jock
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Post by 998automan on Sept 22, 2014 11:12:29 GMT
Hi Jock, thank you. Great tip! Am struggling to find anyone selling a decent mineral 10/40 anywhere (even on line) Would 15/40 be worth considering seems to be loads to choose from in this grade!!
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Post by jockduck on Sept 22, 2014 23:13:23 GMT
Hi, Yes as long as its not intended for the latest engines. Jock
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Post by 998automan on Sept 23, 2014 19:43:32 GMT
Hi Jock, mine is 1987 so I am guessing that this would be ok? Thanks Mike.
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Post by openclassic on Oct 20, 2014 20:52:38 GMT
Hi Mike, Welcome to the forum. Sounds like you are doing all the right things with the regular oil changes etc. I would recommend trying some Valvoline VR1 20/50 mineral oil, its a racing grade oil and although it's 20/50 it is more like 10/40 due to the fact it's race grade.
I had all the same problems as you describe above, but after switching to this i have cured it. (Well....it's back again now to a degree when it's cold (the flaring in 3/4) but that's because I have done about 2,500 and it now needs the oil renewing again.
I expect you have done your oil change by now but if your problem persists it's worth trying, you can buy it in a 5ltr black plastic container for £24.29 freepost. I have just bought some more from a seller called "nielsencdg". I would avoid even semi synthetic like the plague, it's just not suitable for our use, as we expect our engine oil to also be ATF. I put a halfords 10/40 semi-synthetic in mine and the slippage was so bad I had to take it out and do two more oil changes to flush it out. The more you can minimise the slippage the less likely you are to wear out the brake bands. The valvoline seems to come well recommended by others too. - other brands are available of course lol. You are quite right that 10/40 mineral oil is a bit awkward to find. If you are doing regular oil changes I think 20/50 or 10/40 should be fine in the UK climate anyway. Thinner is better in winter (10/40) or this Valvoline 20/50 racing stuff.
Hope this helps if you haven't already sorted it.
Kind Regards,
Simon.
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Post by forever17 on Oct 21, 2014 13:39:47 GMT
totally agree with Simon, Iv used Castrol 20/50 for the last couple of years, changed every 6 months,about 700miles, which has been ok after the oil has warmed, always some flaring for first mile or two. changed to Valvoline last week and no flaring. cant believe its a total cure but time will tell. graham
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Post by 998automan on Oct 23, 2014 21:17:15 GMT
Thanks Simon/Graham. Yes I have done the oil change and went for Halfords mineral 15/40 as this seemed to be the same spec as the Mobil oil but a bit cheaper. It as made a small improvement to the flaring but with the colder weather coming on it is more noticeable again. I find that allowing the car to run up to temperature before driving off helps too, but this is not always practical! Will try the Valvoline next time, thanks for the tip guys! Cheers Mike.
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Post by jockduck on Oct 23, 2014 23:57:13 GMT
I know that the later cars could not select 4th manually so this tip is of no use to those owners, before I set off after starting the car I select 4th gear and wait with my foot on the brake until the transmission starts to load up this fills the top/reverse clutch with oil, then I select Drive and proceed normally, the reason for the flaring is the cold oil is sluggish at filling the clutch hydraulics, "pre-filling" does help a bit but the first 3-4 up changes will still flare with provocation. Later cars should be better as they have bigger T/R clutch oil ways, anyone want to confirm this? Jock
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Post by openclassic on Oct 25, 2014 22:15:12 GMT
Your right Graham there aren't any total cures but I found the valvoline is about as good as I've had mine anyway. When it gets really cold I still need to do a warmup for 5or6 mins and I tend to cycle through all the gears with my foot on brake in the driveway before setting off. My theory being that the oil will cycle through the auto box valves/oil ways etc before setting off. This is along the lines of your theory Jock, I can see exactly what you mean with this idea. Mines a fairly late one being a 1992 rover, but getting that warm oil around the whole box before setting off stops any slippage risk in the first mile or so I find. I have to make sure the transmission and engine are firmly locked together particularly in my case as all my journeys start by crossing a busy dual carriageway! Lol generally I think I am being more careful than I need to be now as the regular oil changes and correct oil have sorted it. Regular use is essential too, if I leave it for say a month without using it then some of the symptoms creep back in. 15/40 mineral sounds ideal let us know how you get on, Kind Regards, Simon.
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Post by forever17 on Dec 13, 2014 14:57:54 GMT
just a quick update to my contribution to this post. had the Valvoline oil in for a couple of months now, the last two start up have been on cold mornings, still leave a few minutes after start up, but the flaring is noticeable less, sometimes none at all. it may be a bob or two more expensive but Ill be using again. graham
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Post by tony105 on Dec 13, 2014 16:35:19 GMT
Very interesting responses to 998 automans post. My 1996 Mini Mayfair had a flare up between 3rd and 4th gear. After a re'build it was improved but like many of the contributers have mentioned, it can come back when cold, or when the oil needs to be changed. I have since the re'build of my transmission used classic 20/50 - which I realise is a subjective choice but has in all honesty appeared to suit the automatic box much more. I wasn't aware that - with foot on the brake- going through the gears before starting to be helpful' I will try this.
The issue of 'flare up' seems to be common in both the early and later box and wonder if is a common issue to all automatic Minis and if anyone is aware was ever known to Rover Group?
I will give the Valvoline a go next oil change I think - does anyone know the best place to buy this?
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Post by forever17 on Dec 14, 2014 9:11:03 GMT
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Post by 998automan on Nov 12, 2015 20:02:27 GMT
Thanks everyone. I have also decided to try the Valvoline as the flaring has started to get worse with the colder weather. I am aware that quite a bit of oil remains in the torque converter after draining the sump, does anyone know if it is possible/advisable to empty the torque converter by turning the engine over by hand after draining the oil?
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Post by Stu on Nov 12, 2015 22:59:36 GMT
I dont think that'd really work. The stator inside the convertor would probarbly prevent much oil flow through when by turning over by hand. I doubt you'd get much out of it. Another way would be to take off the convertor and lay it engine side down over a container. The oil would drain out of its own accord then. Thats assuming you enjoy trying to remove convertors and flywheels from crankshafts. Who doesnt eh
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Post by jockduck on Nov 13, 2015 10:17:34 GMT
There are a couple of plugs on the periphery but I would not touch them, brass and very shallow heads. Jock
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Post by mra-minis on Nov 13, 2015 15:36:56 GMT
just a quick update to my contribution to this post. had the Valvoline oil in for a couple of months now, the last two start up have been on cold mornings, still leave a few minutes after start up, but the flaring is noticeable less, sometimes none at all. it may be a bob or two more expensive but Ill be using again. graham Flaring is often the result of poor grade choice, ie 1979 onwards should in most cases use 10W40, the slightly lower viscosity than 20W50 allows pistons and valves to do their design intended job at the correct speeds thus helping to eliminate flare, however once flare starts unless controlled quickly it will burn the clutch plates and or bands causing irreversible damage.
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Post by mra-minis on Nov 13, 2015 15:41:27 GMT
Very interesting responses to 998 automans post. My 1996 Mini Mayfair had a flare up between 3rd and 4th gear. After a re'build it was improved but like many of the contributers have mentioned, it can come back when cold, or when the oil needs to be changed. I have since the re'build of my transmission used classic 20/50 - which I realise is a subjective choice but has in all honesty appeared to suit the automatic box much more. I wasn't aware that - with foot on the brake- going through the gears before starting to be helpful' I will try this. The issue of 'flare up' seems to be common in both the early and later box and wonder if is a common issue to all automatic Minis and if anyone is aware was ever known to Rover Group? I will give the Valvoline a go next oil change I think - does anyone know the best place to buy this? 20/50 in a later 1979-on auto mini will kill it eventually, ie a lot quicker than using the correct grade of 10W40 As you are experiencing flare when cold and or full of debris.... ie the oil is thicker then changing to 10W40 is the way to go, or even 5W40. I always install 10W40 and advise all my customers with 79-on auto minis to do the same, the main reasons are that the later boxes where designed around 10W40 and do not operate correctly with 20W50. PS with several customer builds that exceed 80BHP and a few that exceed 120BHP that are all using 10W40 and quite a few members on here using my builds direct from me or my trade customers.....
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Post by 998automan on Nov 13, 2015 18:38:16 GMT
Thanks for that. I Have looked at this before but couldn`t find any 10/40 mineral so I went for 15/40, but to be honest it isn`t any better than with the 20/50! The Valvoline is no longer £25, cheapest I could find was £32 for 5L
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Post by mra-minis on Nov 13, 2015 19:53:39 GMT
Thanks for that. I Have looked at this before but couldn`t find any 10/40 mineral so I went for 15/40, but to be honest it isn`t any better than with the 20/50! The Valvoline is no longer £25, cheapest I could find was £32 for 5L Oil has recently taken a large hike whilst petrol has reduced in cost !!! bizarre to say the least. in the UK 10W40 is readily available in semi synthetic which has been good in everything upto about 75/80bhp as above that I opt for Unipart or castrol GTX 10W40
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