3rd gear not working.

[chris1980]

Hi,I wonder if any of you have had the same issue as me. I have a 1979 mini 1000 SDL. It's been running fine until today. I went out in it in the morning and it seemed to loose drive for a second on a flat straight road. Then again on a roundabout when I was 'enthusiasticly' going round. Drive came back. So while my daughter had her swimming lesson I checked the oil. It was right down,like way below minimum. I ran to a local shop and got some 20w50 for classic cars,the green oil. Topped it up and all was fine again. That was until later that day I went out in it again. I went to park on the street,I lost reverse completely and the shifter was stiff to move. I eventually got parked up. Came back to the car 10 mins later. The shifter was back to normal but when I drive 3rd gear it revs it's nuts off until I shift to D and then it's ok. If I shift back down to 3 it revs up again. If I drive gently it gets to top gear all ok. Has running low on oil screwed it up or maybe too much oil?

[jockduck]

Hi, yes running low on oil will cause the gears to fail to engage you should get a flickering oil pressure light just to confirm, others on this site will say that 20/50 oil is not correct for an automatic mini a manual yes. I was going to say that your gear cable is not correctly adjusted but the selector going tight and then coming good would suggest something wrong with the selector linkage at the gearbox end. It would be interesting to do a pressure/stall test but get the oil level correct first.
Jock.

[notamini]

Jock. You forgot to mention the correct oil type. MA2 10W40 for motorcycles with wet clutch.

[chris1980]

As regards the oil I keep hearing different opinions about the oil grade. But for now I will use this till the next oil change. I cannot find mineral 10w40 anywhere local to me. I topped the oil up last night bang on the lever and I've checked this morning and it's back on minimum. ?. No puddles under the car,so where has it gone? I've had manual minis for years this is my first auto.

[mikerotherham]

Are you following the correct method to check the oil level?

1) make sure vehicle is on a level surface

2) run the engine for 1 to 2 mins

3) stop and wait for 1 min

4) then check the dipstick

The oil level and correct oil grade is vital.



Earlier autos used 20w50 but for later ones Rover specified 10w40.

[jockduck]

The reason I did not mention MA 2 oil is that I don't use it! Still using 10/40 mineral oil. A significant failure in an AP box is not going to get fixed by a slight change in oil type.
Jock

[notamini]

I agree with you Jock. That appears to be way too much loss unless somehow you have had an empty filter and almost empty converter too. Hope it isn't going into the coolant or out the exhaust. Mostly kidding.

Back when I had my first automatic 1300 Austin all I ever used was 10W40 mineral and it ran flawless for 5 years. Now on this 1300 Austin I have had varying success with the 10W40 mineral so I switched it up for the MA2. There is also 10W30 MA2 you can use. I'm wondering if the 'advancements' in the production of oil and its additives has something to do with it. Maybe Richard can ring in and tell us.

[chris1980]

Ok I've got the oil bang on the level as per the instructions given but it still misses 3rd. All of the other gears work perfect in both manual and auto function. What would be my next step in checks? I'm loosing faith in this car or more to the point the gearbox.

[jockduck]

Hi again, is the box missing 3rd only in automatic or can you still find it in manual? If third has gone completely its probably the third gear band failed, If third is there in manual it suggests a valve box issue. A pressure/ stall test is probably a good idea, you really need a good manual to show how to do this.

The auto box is a bit of an acquired taste but I prefer it to manuals despite its issues.
Jock

[notamini]

Hi Jock. Chris said "when I drive 3rd gear it revs it's nuts off until I shift to D and then it's ok. If I shift back down to 3 it revs up again"
Since it is the reverse situ, he must have a something going on with the manual selector valve. Do you think it possible to just have the selector cable slightly misaligned? The D position selects via the governor but the manual selection is via the shift cable. Beyond that I can only guess it is the 3rd band.
Chris if you need any manuals, I can upload them to you.

[jockduck]

Hi, yes!! I re-read the original post and I am still not clear if third engages OK in auto. it would be interesting to see the oil pressures to see if there is pressure when third is engaged, if there is then pull off the front cover and check bands. getting to be a big and messy job. I suppose its possible to burn out the third gear band if there is insufficient oil pressure to engage it properly but it would take time.
Jock

[chris1980]

Thanks for the help guys. Yes 3rd does not work in auto or manual. In auto it slips and then changes up to 4th. In relation to the oil,if I change it for 10w40 do you think there's a remote possibility the valve for 3rd would start to work again? I'm thinking along the lines of the 20w 50 being too thick.

[notamini]

It couldn't hurt since likely the removal of the front plate to check the band would be your next move. Do you have a good service manual?

[chris1980]

I've gone through my manuals and there's very little coverage of the autos. Even in my old BMC manuals. Is there a step by step guide to adjusting the bands?

[notamini]

Send me a PM and I'll send you a link to download all my present materials including full instruction on the auto. Also, look at this site Austin America under technical advice/AP Automatic Transmission.

[mra-minis]

I can be contacted on [e-mail]

10W40 is the correct oil for almost all applications of automatic, and all later manuals as well**, there is a belief that 20/50 should be used because its an old car, this is total nonsense, I see issues with various AP 1 & 2 transmissions on a daily basis, I can tell almost straight away when the wrong oil has been used by certain failure modes, for instance fwd clutch issues are almost always down to incorrect oil or poorly set cable, unless the seals are hard where its down to lack of care and attention (service intervals) if you choose to use 20w50 oil and you drive the car very gently most issues will not show up until a much higher mileage has been covered however they will still be there and they will still occur unless the debris in the VB kills it first.

What the OP has here is a dodgy 3rd gear valve in the valve body, it will only get worse and because the OP is still driving it with the fault it will not be a simple quick cheep fix, this will need a full strip and rebuild to rectify and most likely a TC flush.

But the bottom line is 20w50 is not suitable for the AP1 or 2 transmission and whoever tells you it is really doesn't know the transmission from a repair and or service life of the 90 percentile driver.

As we recondition these units we are in a quandary, on the one hand using 20W50 gives us more work and on the other hand I want to see my customers driving their Mini, ADO16, etc variants not forking out a wad of cash for unnecessary repairs.

** Some locations may need a different grade due to the local climate, be it excessively hot or cold, for 90% of the world 10w40 is the best option.

[mra-minis]

May 12, 2021 1:54:30 GMT chris1980 said:

I've gone through my manuals and there's very little coverage of the autos. Even in my old BMC manuals. Is there a step by step guide to adjusting the bands?

I can be contacted on [e-mail]

Adjusting the bands is NOT usually something that needs to be looked at, what you have to realise is there is a small amount of slack needed, but be careful not to lift the bands off their 3 seats within the transmission as you will then get tie up in gear, this is where you engage more than one gear, so excessive heat and wear will occur.

[mikerotherham]

May 12, 2021 1:54:30 GMT chris1980 said:

I've gone through my manuals and there's very little coverage of the autos. Even in my old BMC manuals. Is there a step by step guide to adjusting the bands?

I don't know if many people are aware but there is quite a bit about servicing and repairing the AP2 automatic in the Rover manual AKM 7169.

I have included a link below but it appears the PDF was created by just scanning. It doesn't appear to be possible to use the search function.

miniscene-unterfranken.de/wp-content/uploads/downloads/Mini_Repair_Manual_92-96.pdf

[notamini]

I found this a number of years ago but then lost the link. This is great news. The manual is very extensive and worth keeping esp for those with a newer mini like Rovers. I'm going to download this and add it to my library for others to download. Thanks.
Mark

[mra-minis]

I can be contacted on [e-mail]

And anyone who wants parts or special service tooling I can help

[richard1]

May 3, 2021 22:48:22 GMT notamini said:

I agree with you Jock. That appears to be way too much loss unless somehow you have had an empty filter and almost empty converter too. Hope it isn't going into the coolant or out the exhaust. Mostly kidding.

Back when I had my first automatic 1300 Austin all I ever used was 10W40 mineral and it ran flawless for 5 years. Now on this 1300 Austin I have had varying success with the 10W40 mineral so I switched it up for the MA2. There is also 10W30 MA2 you can use. I'm wondering if the 'advancements' in the production of oil and its additives has something to do with it. Maybe Richard can ring in and tell us.

Yes I will chime in. Haven't been too regular, but here I am.

20W-50 does not flow very well to clear off the discs and let them grab.

Once upon a time, we had what was called "Universal oil". Gasoline, diesel - one oil fits all. Then the governments started pushing economy and higher mpg, while adding catalytic converters that could be contaminated by too much ZDDP (a zinc/phosphorous compound), so that was reduced and friction modifiers were added to gasoline oils to make them more slippery. While this helps modern cars economy, it is murder on wet-clutches, as they slip and wear, making for slipping shifts and fiber in your oil.

These friction modifiers were never added to diesel oils, as they don't really benefit by them, having much more pressure, and jumping right into the need for ZDDP. So they were adequate for motorcycles, and most could pass the MA standards for wet clutches. Then the motorcycle people started trying to improve their shifting (gain a few seconds in races), and developed a new standard of dynamic friction, creating a new category. MA now is divided into MA1 (meets the old standard) and MA2 which is much better grab of discs. Some diesel oils meed MA2, although probably at the bottom of the standard. Motorcycle specific MA2 can be near the top, although no one will tell you where they are in that range. They do not have to be synthetic. I run a mineral MA2 10W-40 in my Mini. An MA2 should not cost more than 5 to 10% more than a car motor oil of a similar quality.

EDIT: And I read Martin's note about the valve and the seals/o-rings. Sometimes we don't change oil frequently enough because we think we haven't put enough miles on them. That causes the seals to dry and shrink. Bad idea. You need an oil change at least once a year, whether you drive 1000 miles to 5000. And if I was in the OP's position, I would consider a treatment with AutoRx or something similar with synthetic esters. If the problem with the valves is varnish, or sludge, it will resolubilize this and clear the problem. If not, it has only cost you $30 or so (depending on shipping and taxes). (I sell a similar product for $10, but not in the UK)

Tarija and Santa Cruz, Bolivia

[jockduck]

Something occurred to me because I could not quite get my head around your problem " when I drive 3rd gear it revs it's nuts off until I shift to D and then it's ok." I was wondering if the "reving its nuts off was a change into 4th flare, because if its slipping in 3rd then the car speed would not rise enough for the box to select 4th. The flare into 4th is a common AP problem. I think to progress the issue you really need to do a pressure/stall test.
Jock.

[mra-minis]

Jun 2, 2021 8:45:15 GMT jockduck said:

Something occurred to me because I could not quite get my head around your problem " when I drive 3rd gear it revs it's nuts off until I shift to D and then it's ok." I was wondering if the "reving its nuts off was a change into 4th flare, because if its slipping in 3rd then the car speed would not rise enough for the box to select 4th. The flare into 4th is a common AP problem. I think to progress the issue you really need to do a pressure/stall test.
Jock.

I can be contacted on [e-mail]

Always a good idea to do a pressure and stall test (no longer than 10 seconds at a time) but would it achieve what is needed ? the pressure test would normally only be conducted whilst in the "manual" setting of 3rd and 4th both of which work ok in that setting, the only way to tell would be to use a "partner / friend to take readings as the car is being driven along, watching for anything abnormal.

[mra-minis]

I can be contacted on [e-mail]

This issue is more than likely a 3rd gear valve issue in the valve body, however now it will need at the very least a full srrip and rebuild to clear out all the nasty debris, most probably a reconditioned or repaired valve body as the piston is sticking in it's bore, it's often caused by debris "kicking up" a burr in the bore of the valve, this is not a simple fix as there will be a gauge and or roughness that will cause other issues like early upshift or worse tie up.

[notamini]

Martin, what would be the symptom from the reverse valve (inside the main transmission shaft) not operating properly?

[mra-minis]

Jun 2, 2021 12:53:42 GMT notamini said:

Martin, what would be the symptom from the reverse valve (inside the main transmission shaft) not operating properly?

I can be contacted on [e-mail]

It depends in which mode did it fail ?

[notamini]

Since it is involved with the selection of top gear or reverse gear, I was wondering what might happen if it stuck partly open. Would top and reverse fight each other?

[mra-minis]

Jun 2, 2021 12:53:42 GMT notamini said:

Martin, what would be the symptom from the reverse valve (inside the main transmission shaft) not operating properly?

I can be contacted on [e-mail]

1) If the valve was stuck closed, then it wouldn't affect 3rd to 4th upshift, but reverse may slip under load
2) If the valve was stuck open, then 3rd to 4th would flare on upshift and should eventually "drop in to 4th as long as the speed carried the upshift, and it wouldn't cause any issues to reverse gear