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Post by dieselpaul on Apr 24, 2019 18:05:41 GMT
I have a 1992 Japanese Mini, I've had it about a year now and I've put ~2,000 miles on it.
I am using the Jaso Spec2 10/40 Oil as recommended by my reading on here.
I am having an issue that when the transmission is hot if I reverse, the car goes straight into reverse and backs up, but when I shift into a forward gear nothing happens. If I apply a little throttle it will bump into gear, violently if you really give it a lot of throttle. Once it bangs into forward gear it is there to stay, I have no slipping issues in other gears, stop and go traffic I don't have any issues after the initial bang into forward gear at the beginning of my drive. Once I'm in gear it takes off from subsequent stops just fine. I hope I am expressing myself clearly, trying to best describe the issue.
When the transmission is cold it seems to do this less, and reverse does not act up hot or cold.
Also on my car when I first start it the low oil pressure light stays on, if the low oil pressure light is on and you put it in gear, the car will not move. If I blip the throttle in neutral, the low oil pressure light goes off, stays off, and the car moves just fine. I've driven the car in the summer in stop and go traffic and the low oil pressure light never comes on, so I am not worried about the health of my engine itself.
I was doing some reading on write-ups of rebuilding/repairing the AP auto, but I wanted to talk to those who knew more before I dove into it. Hoping you guys can point me towards a bad o-ring, or a forward clutch pack rebuild/replace.
Oil level is good, if anything a little high, the car does not consume oil. The oil is nice and clear as well.
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Post by jockduck on Apr 25, 2019 11:26:29 GMT
Hi, Sounds a bit like the valve block is a bit sticky, There is a valve that controls the output from the oil pump and it sounds like its playing up, it would also be worth while checking the adjustment of the gear level cable. I presume these faults occur while using the "drive" selection, when it wont take off try selecting "1" manually to see if anything different happens.
Personally I would keep using the car and hope that clean oil will fix the problem over time. Pulling the engine/box is a big job and not to be considered lightly
Jock
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Post by dieselpaul on Apr 25, 2019 15:55:43 GMT
Is there any accessing and cleaning that valve?
Is there a write up on how to properly adjust the cable, when I search I mostly get references to people needing to do it, but no real walk through on doing it.
As for pulling the motor, I don't consider it lightly, but I do have a full workshop with a hoist, I restore and collect cars for a hobby. However, I know when to admit I am in totally new territory on the AP automatic so I am definitely here to learn.
I initially was using the wrong oil (20w50 at the suggestion of a Mini parts house) then I switched to the Jaso spec oil when I joined here. So there are definitely a few liters of 20/50 and whatever the previous owner was using so I'll do another change soon with the proper oil.
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Post by notamini on Apr 25, 2019 16:14:34 GMT
Does the low oil light come on when you are sitting still and in gear (warm or cold)? what is your idle speed? Timing?
I have found all of these to affect the transmission operation.Too much oil has caused mine to 'leap' into gear and leak oil badly on startup.
Mark
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Post by limby2000 on Apr 25, 2019 17:33:23 GMT
Yep, sounds like low oil pressure/level to me.
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Post by dieselpaul on Apr 26, 2019 18:23:34 GMT
Does the low oil light come on when you are sitting still and in gear (warm or cold)? what is your idle speed? Timing? I have found all of these to affect the transmission operation.Too much oil has caused mine to 'leap' into gear and leak oil badly on startup. Mark No, after the initial startup the low oil pressure light goes out and stays out until I turn the car completely off. I will have to go outside and check my idle speed. If anything my oil level does appear to be on the high side, it didn't occur to be too high of oil level would cause an issue like this, seemed more like a too low fault, but again I don't know these transmissions. |
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Post by dieselpaul on Apr 26, 2019 19:22:45 GMT
  
That is idle in neutral (~900rpms) and then my idle in gear when gear is engaged (~500 rpms) it happened to go straight into forward gear today with no hesitation. I also checked my oil before I started (car had been sitting about 1 week), then 5 minutes after I shut it off and both times it read significantly overfull (I read something about torque converters draining back on these and it making the level appear higher so I wanted to check dead cold, and after it had had chance to fill the TC if that was a thing). So at a minimum tonight I'll be draining out a few liters of oil and getting the level right. |
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Post by dieselpaul on May 11, 2019 16:40:02 GMT
Changed the oil with more of the JasoMA2 10/40 and it is still doing it.
Are there any adjustments on this transmission I should be checking?
If I do need to do a refresh is JPAT still who you buy parts from? I cannot find contact information for them.
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Post by limby2000 on May 12, 2019 19:44:06 GMT
Jpat or John Guess or Martin Altria.
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Post by dieselpaul on Jun 20, 2019 15:39:16 GMT
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Post by limby2000 on Jul 16, 2019 14:18:03 GMT
A member on here called Stu done a photo strip down, i rebuilt mine and tbh i was,nt has bad as i thought it would be, did you get bands too, as every box i ever stripped down had bad wear to the top/reverse band (the fat one). You can also improvise with most of the service tools too. Ideally take photos as you break it down and reverse the sequence to rebuild. You,ll probably find most of your seals have hardened or cracked!. good luck.
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Post by dieselpaul on Jul 17, 2019 23:04:39 GMT
Thanks for the advice, however it appears that Photobucket took out all the photos to his rebuild thread.
What is strange about my transmission is in the top/reverse clutch only 2 friction discs and 2 of those wave wire rings came out. Most photos I see show 3 discs coming out, and the number of metal plates also suggests I am missing a friction disc. But the car was driving fairly well before. Is it possible the car would have driven fine missing a disc?
Does anyone have information on adjusting the brake bands? All 3 of them were adjusted to wildly different amounts of play, I wouldn't be surprised if that was a big part of my issues. It appears this transmission has been apart before.
All of the bands have some material flaking off and all of the clutch discs have some pitting to the wear surfaces. Nothing totally worn out, but I see lots of small issues. Which sort of makes sense because 95% of the time the car drove fine.
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Post by jockduck on Jul 18, 2019 11:24:21 GMT
Hi, I have no experience of later automatics(you MUST get a relevant manual) I looked at the Jpat drawings and the forward clutch has two friction plates, the T/R clutch used to have 2 frictions for the 850 + 998 engines the 1100 + 1275 have 3, I think the Austin America site has a bit on modifying a 2 plate clutch to a 3. The clutch bands are normally long lasting but should be checked and the manual has the settings, A couple of other bits worth checking while its all in bits, The oil pump drive spider can strip out I make up a spacer to ensure it engages the the splines properly. The two bearings that support the big differential gear can loosen in their housings and spin destroying their pre-load. you need a special spanner and a big spannner to loosen the nut to re-shim and loctite.
Doing the autobox is not great drama, 1960's technology so not rocket science.
Jock
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Post by dieselpaul on Jul 18, 2019 20:15:33 GMT
My forward clutch does only have 2 and my car is a 998. I did not want to attempt the austin america writeup mod.
I am talking about what the austin america calls the "top/reverse" clutch pack. In his pictures he shows 3 clutches. I have enough intermediate plates that I would expect there to be a third clutch. However no clutch. I'll go get some pictures.
I cannot find the manual, I have emailed a few people on here who claimed to have it, but their posts are several years old so they may not be in the community anymore.
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Post by limby2000 on Jul 27, 2019 13:01:58 GMT
Hi Paul, i,m pretty sure the 998 has only 2x frictions in both the forward clutch pack and the top aand reverse, where as all the later 1275,s have triple frictions in both. What year is yours?.
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Post by puddingmobile on Jul 27, 2019 14:02:24 GMT
Foulis manual has a clear explanation that small bore clutches have two friction plates, while 1275 have three. If there is an extra steel plate it might just have been installed to shim the clutch pack up to spec. Attachments:
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