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Post by steve69aaa on Oct 9, 2018 23:47:15 GMT
I'm just about ready to put my Austin America in storage for the Wisconsin winter. Before I do so, I might be pulling the engine in order to diagnose a 4th gear flare up problem that I have been having. I recently changed the oil and am running Valvoline 10W-40 Motorcycle oil in it. I also added a bottle of break-in zinc additive: lucasoil.com/products/engine-oil-additives/engine-break-in-oil-additive-tb-zinc-plusI am wondering it the additive might be part of the problem? I'm lucky that my torque converter had two plugs in it, 180 degrees apart, so I can fully drain and fill it when I do an oil change. Maybe a quick oil change without the additive, before I decide to pull the engine/trans? thanks, Steve |
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Post by jockduck on Oct 10, 2018 10:16:19 GMT
Hi Steve, the flare from 3rd to 4th is fairly common on early AP boxes especially when the oil is cold. my mini has been doing it since we moved to a colder climate 10 years ago, I just drive around it for the first mile or two and once its warm its good, I recently changed from 20-50 to 10-40 oil and it has only made a slight improvement. Low friction additives like molybdenum, teflon and graphite are a bad idea but zinc and phosphorus are in ordinary engine oils at varying levels. There was/is a long running thread on Lucas autobox additive on this site somewhere, I think the conclusion was it was of little or no use. Was the box flaring before using the additive? Does the box flare when warm ? Additives can bond with the surface of the clutch plates so dumping the oil/additive may not help much.
Jock
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Post by steve69aaa on Oct 10, 2018 14:47:46 GMT
The flaring up has been recent - since the last oil change and using the additive. I have used it in previous oil changes, but maybe not as much as I did this time. The flare up varies - sometimes warm, sometimes cold, and at varying pedal pressures...I was just manually shifting, but then it started doing it while manually shifting from 3rd to 4th.
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Post by notamini on Oct 10, 2018 16:10:22 GMT
My America has been doing this for 14 years. When hot, top gear is fine but cold sometimes works and most times doesn't. When I got it in 2004 the oil was probably 5-10 years old.Each oil change has made it better. Now I have 10W40 with MA2 in it. This has been the best result.
I suspect the anti reverse valve in the centre of the clutch assembly shaft has been sticking with all the junk in the oil (old oil and additives). It sticks worse if I first start to move in reverse when cold and then select a fwd gear. If it sits a few days and then I drive fwd immediately, top gear is much better. Still not perfect until hot. But when hot, 1st and 2nd chatter if I accelerate too fast from a stop. I'm hoping the transmission just needs proper alignment of the bands etc.
hope this helps you.
Mark
Ontario, Canada
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Post by steve69aaa on Oct 12, 2018 23:56:59 GMT
I did some further testing today. The flare up varied with engine load. But, I had it in 4th manually and was going about 30mph and stood on the gas. The rpms climbed but not the speedo. I am not attributing it to the new exhaust header and 1.75 exhaust that I recently installed... When sitting still and putting it through the gears, it did not slip, but on the road it did. Looks like it's time for a new clutch set.
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Post by limby2000 on Oct 17, 2018 11:30:56 GMT
How old is your box, it could just be coming to the end of its life, due to wear. When the friction are worn, there worn. My friends mini city, was slipping on 18,000 miles. When he stripped down, it was just worn.
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Post by jockduck on Oct 18, 2018 10:08:45 GMT
My 1968 998 Minimatic is up to 35000 miles since last rebuild, and has been flaring when cold the whole time, once its hot everything is fine, The early boxes had a more restricted oil feed to the top/reverse clutch than later boxes, would owners of later cars say that their cars are better?
Jock
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Post by richard1 on Nov 14, 2018 23:16:33 GMT
I'm just about ready to put my Austin America in storage for the Wisconsin winter. Before I do so, I might be pulling the engine in order to diagnose a 4th gear flare up problem that I have been having. I recently changed the oil and am running Valvoline 10W-40 Motorcycle oil in it. I also added a bottle of break-in zinc additive: lucasoil.com/products/engine-oil-additives/engine-break-in-oil-additive-tb-zinc-plusI am wondering it the additive might be part of the problem? I'm lucky that my torque converter had two plugs in it, 180 degrees apart, so I can fully drain and fill it when I do an oil change. Maybe a quick oil change without the additive, before I decide to pull the engine/trans? thanks, Steve
That additive is very dangerous. There is a SAE technical paper that says anything over 1800 ppm of zinc can cause galling of cams and other steel parts, and 2000 ppm definitely does. According to the Lucas page you posted, one tube, with 4.5 quarts of oil, will give you 5000 ppm. That is 2 ½ times the danger limit. That zinc is working hard to keep your discs from engaging. |
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Post by steve69aaa on Aug 27, 2019 20:36:10 GMT
UPDATE: I decided to go all out and pull the engine/trans and rebuild both. I know that a loss in oil pressure affects both. The cylinders/pistions were fine, but I installed new rod and crank bearings and new cam bearings, too. I had the head cleaned up while I was at it, as well as having the crankshaft turned for the new oversize main bearings. I replaced all of the O rings in the transmission as well as the cast iron rings and the rubber cups in the servos. I found a new shuttle valve and valve block, too. The brake bands still look like new. I had a spare original trans, so I swapped the clutch plates so all are bronze now. Once I fired it up, the oil pressure was great - so much so that I developed a leak at the torque converter, but took care of it by using a bit of Yamabond at the joint of the TC face and put copper washers on the TC bolts. But - I no longer have flare up into 4th gear because it does not want to shift into 4th - automatically nor manually. I've double-checked the shift rod, etc. I did find that since I went to an exhaust header and separate intake manifold that the kickdown lever could not be adjusted enough, so I had to lengthen it. I don't think that this is the cause of the trouble and am hoping that I missed something. It was easy to line everything up with the engine out of the way and I am confident that it is not the top/rev clutch. (Though I did almost leave a rag on top of my trans while lowering the engine onto it...  Any clues on why it won't go into 4th? There are no brake bands engaged while it is in 4th, so I am wondering if it is the valve inside the top/rev clutch... I'll be doing a pressure test tonight. I'm happy with the new oil pressure and the engine is running the best it ever has - so that's the good news. But I would like 4th gear back... |
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Post by jockduck on Aug 28, 2019 11:12:19 GMT
Hi, sorry to hear 4th has gone AWOL, I am a little worried about the comment about new shuttle valve and valve block, there was variations of valves and valve blocks, certainly would be interesting to check oil pressure when trying to engage 4th there are two small plugs on the governor cover one is for the forward clutch and the other is for the top/reverse,
Does reverse work ?
Jock
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Post by steve69aaa on Aug 28, 2019 11:52:20 GMT
Yes, reverse does work. I was going to pull the plugs on the governor cover and check for pressure. I am also worried about the valve block --- The one I had, had the brass fitting off one of the ports, the new one did not so I removed the end plug and installed the fitting from the old block. I have read that they vary slightly, but could find no specifications on how exactly they are different. They had the same ID number stamped on them, but I realize that it could just be a number for the casting itself....I did save the old one.
I wish there was a way to determine if possibly my 3rd gear servo is hanging up.
My trans is a MKIIA and the valve block etc is as shown in the picture. Attachments:
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Post by richard1 on Aug 28, 2019 14:27:48 GMT
Tarija and Santa Cruz, Bolivia
I'd bet you have the same problem I have, and need to fix. From what I've been told and pictures posted (don't remember where), I probably put my kick down lever into the transmission on the wrong side of the lever in the transmission. I just haven't had time to drop it again and change it.... So mine goes fine up through 3rd, but no 4th yet, just like yours.
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Post by steve69aaa on Aug 28, 2019 14:43:21 GMT
Thanks Richard - I'll check that out. I compared it to my spare transmission and it seems to be correct. I actually just lengthened my kick down rod because the new separate intake manifold must have a different geometry than the stock intake/exhaust manifold and it was too short to thread into the plastic piece...
I checked at lunchtime and I think that you are correct. I was looking at the position of the "lever" with the throttle closed and it is very close to what it should be, but if the lever is on the wrong side, it's hard to tell. What I did check was this ... With the throttle disconnected, you should have lots of resistance if you attempt to move the lever counterclockwise (towards the front of the engine). If it moves easily, the lever is on the wrong side. I'll be putting it up on blocks tonight and using my 1/4" drive set to get at those 2 bolts. I remember that I had a problem with the linkage when I was installing the engine/trans, so I probably goofed it up when I reconnected it... I'll report back later tonight... |
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Post by steve69aaa on Aug 29, 2019 1:28:42 GMT
Well, spent several hours getting at those 2 bolts, putting it back together and adjusting the kickdown rod and it is the same. Upshifts great. Comes out of 3rd gear, but 4th just doesn't engage...
Time to move onto the hydraulics...ugh
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Post by jockduck on Aug 29, 2019 11:24:14 GMT
I think the valve block you have is one that is specifically for the 1100/1300 and it has extra relay valves to reduce "flaring" when shifting from 2,3,4 gears either auto or manual, I don't think this type of valve block was fitted to Minis, kind of an admission that the factory knew that there was a flaring problem.
I have an Australian Leyland manual for 1300/1500(E series engine) that shows some of the changes.
Jock
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Post by steve69aaa on Aug 29, 2019 12:39:18 GMT
Thanks Jockduck - Yes, my plan is to do a bench comparison from my spare, older transmission valve block and the one I took out... Aside from the fitting for the shuttle valve pipe, what other differences are there? |
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Post by steve69aaa on Aug 30, 2019 1:50:57 GMT
I did a side-by-side comparison of the MKIIA valve block and a MKIA valve block I have from a spare trans (without the shuttle valve). They are identical, except for the fitting to the shuttle valve which is on the MKIIA. So, I am confident that my new valve block is OK. Time to move onto removing the front plate to look for a misguided tube...
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Post by jockduck on Aug 30, 2019 11:06:17 GMT
As far as I understand the same oil tube supplies the top/reverse clutch, so if reverse works then the fault on 4th is elsewhere unless there is a problem with the shuttle thingy in the forward clutch.
Jock
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Post by steve69aaa on Sept 1, 2019 17:14:05 GMT
I checked my oil pressure at the filter head yesterday and it was all within spec.
I also have an oil pressure gauge at a tee where the oil pressure sender is located. That one dips when in 4th or Rev -- 75 in all gears at idle, drops to 45.
I pulled the front cover and checked the brake bands and then the valve body. Everything is as it should be.
I want to check my oil pressure at the auxiliary pump...Anyone know what the normal pressure should be?
And if it is low - how to remedy the problem.
UPDATE:
I performed the pressure test at the auxiliary pump...cold
150psi in Reverse
100psi in 4th
30psi all other gears.
Last year - 4th gear flareup problem.
Total engine and trans rebuild.
No 4th at all now....
strange. What have I missed?
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Post by jockduck on Sept 2, 2019 11:31:41 GMT
OK, since the pressures seem good I'll stick my neck out and suggest there is something wrong with the Top/Reverse clutch, not what you want to hear, I can't think what it could be but reverse has the pressure multiplier and it works in your case, if the 4th oil pressure is getting to the clutch piston the clutch should lock up, which it don't!
Jock
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Post by steve69aaa on Sept 2, 2019 22:33:26 GMT
Everything disconnected and ready to rent a hoist tomorrow...I'll keep you posted.
thanks for the input.
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Post by minicuda on Sept 3, 2019 8:43:31 GMT
I just bought a 74 mini automatic. the same problem will not gear up to 4 gives hope you find the solution. But what is the right oil for these cars?
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Post by steve69aaa on Sept 3, 2019 17:31:31 GMT
I was unaware of the 3 large oil seals inside the top/reverse clutch when I replaced all of the other O rings. I'll make sure that the "pistons" inside the clutch assy is also OK. Everything else checks out. I'll keep you posted. Pulling the engine tonight and tear down after that.
I run non-synthetic 10w-40 motorcycle oil in mine so that it gets enough zinc.
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Post by notamini on Sept 3, 2019 19:30:06 GMT
Steve,
Just curious since I have never pulled my apart. Do you know the date your '69 rolled off the line? Mine was on June 02, 1969.
I don't believe all of the 69's had the shuttle thingy in them but I don't know about mine.
Mark
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Post by steve69aaa on Sept 4, 2019 0:35:00 GMT
The shuttle valve was used on the MKIIA transmissions. I don't know the manufacture date of mine. It has a serial number of 10541 if that helps.
I studied a lot of the manuals today and what surprises me is that I replaced all of the O rings on the piping, etc. But the 3 found inside the top/reverse clutch are the only ones in the transmission that have a shaft slide back and forth on them --- seems like they would be the first ones to check when 4th and reverse start acting up....
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Post by notamini on Sept 4, 2019 21:51:14 GMT
Do you mean something like A-A2S-D/*****-M ?
The * for digits you posted.
Mine is A-A2S-D/35075-M.
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Post by steve69aaa on Sept 5, 2019 2:57:10 GMT
A/A2SAU 10541 M is on my tag. I found the source of my clutch problem. Naturally, the O rings inside the top/reverse clutch are worn. But, the shaft on the inside of the clutch housing (basket) that two of them makes contact with, is chewed up and it is right where the top gear piston O ring is supposed to seat. End gaps on the two piston rings is very close to spec, but I think that the O rings and seating area is the problem. I have a spare trans with a very good clutch housing. I'll swap it out tomorrow and install the new O rings. ****Update***** The O rings needed attention but were not the source of the problem. I think that the bimetal washer under the auxiliary pump got chewed up. The metal debris clogged the Priming valve - whose main purpose is to prevent 3rd-to-4th gear flare up! Attachments:
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