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Post by steve69aaa on Sept 9, 2019 3:06:50 GMT
I pulled my engine/trans again and found out that I had missed the oil seals inside the top/rev "pistons" and two on the shaft. I swapped out the middle "cylinder" because it was worn where the O rings were riding. Still no 4th gear.
I am looking back to last year when I first started experiencing 3rd to 4th gear flare up and was thinking about any other work I had done to the car.
I replaced the entire exhaust system with 1.50" piping, two glass packs and upgraded to an exhaust header and separate aluminum intake manifold.
I had to lengthen my kick-down rod because of it and now I am wondering if the geometry is off enough to be causing the shifting problem...
I have triple-checked everything else and have good oil pressure test results at the filter head and at the auxiliary pump, and basically am running out of parts to replace! Should I disconnect the kick-down lever to test it out?
Any other recommendations would be greatly appreciated. If I have to pull this engine again, I am going to consider swapping it out for a manual transmission.
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mtjm
Senior Member
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Post by mtjm on Sept 9, 2019 8:18:48 GMT
I've run a lengthened kickdown rod on mine for years with no issues. I fitted a MiniSpares Stage 1 kit that came with a Cooper Freeflow exhaust manifold and the kickdown kept hitting the manifold, so I added about 2cm to it.
I'd make sure that the kickdown adjusts properly - with a dowel (or drill bit) through the lower linkage make sure the throttle is closed (as per the workshop manual). Also make sure that you can fully open the throttle with the kickdown attached, as it might still be too short.
Also, maybe check the gearchange points if you haven't already done so - if it is changing up at the correct RPM from 1 to 2 and 2 to 3 at part throttle and then a higher RPM at full throttle then that would indicate the kickdown is working as it should.
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Post by notamini on Sept 10, 2019 16:46:31 GMT
what symptom would you expect if the rod was now too long?
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mtjm
Senior Member
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Post by mtjm on Sept 10, 2019 17:41:01 GMT
what symptom would you expect if the rod was now too long? If the rod were too long I think you'd see the car idle very high (as it would hold the throttle open) and possibly the kickdown itself would never activate. I don't think that's the issue in this case. What might be a problem would be if the rod were still too short - in which case the kickdown might be activated all or most of the time, which would mean very late gear changes, although I'd still expect it to change to 4th, just not til a very high RPM point. The kickdown rod could also potentially be binding on the exhaust or the fuel pump and not returning to the off position, which could cause the same symptoms. If the kickdown rod can be adjusted as per the manual and the gear change points also match the manual then the kickdown could be ruled out as a cause. |
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Post by steve69aaa on Sept 10, 2019 21:52:09 GMT
I agree. Since my lack of 4th gear is in both the manual and automatic positions, the kickdown linkage and governor would only affect the automatic shifting...Still no 4th gear, even in manual mode. But I have Reverse. What the heck....
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Post by notamini on Sept 11, 2019 13:04:09 GMT
Now it sounds like a cable adjustment. It might be reaching beyond reverse but at the other end it comes short of 4th.
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Post by steve69aaa on Sept 11, 2019 21:31:15 GMT
Triple checked all that. Tried every gear in manual mode on the shifter and it aligns perfectly with the pin in the linkage when moving the selector rod. And I have 1st, 2nd, and 3rd in D (lowest position on the shifter)...
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Post by steve69aaa on Sept 13, 2019 13:20:26 GMT
I'm about to pull the engine for the 4th time. My clutches are good. My oil pressure tests are good. All new O rings, etc. Could the gear cluster possibly be hanging up so that it is not dropping into 4th? I'm at wits end..  |
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Post by jockduck on Sept 17, 2019 11:18:28 GMT
I am impressed by your persistence, pulling an engine once is a big deal for me 4 times is heroic stuff, I have heard of professional autobox builders bench testing rebuilt boxes with compressed air instead of oil pressure, I don,t know if you split the engine and box but you can see more of whats going on if the engine is lifted off.
Jock
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Post by steve69aaa on Sept 17, 2019 13:52:22 GMT
Jock - I agree. Easier to handle, too. Plus it makes lining up all the tubes for the fwd clutch easier - you can simply clamp the fwd clutch in place. I'm still not finding anything shocking. I am contacting a local transmission shop today.
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Post by steve69aaa on Sept 18, 2019 2:38:54 GMT
SOLVED! I was meticulously going through everything again and replaced a few more O rings that I had missed in the forward clutch. I was looking at where the fwd clutch splined shaft runs in the auxiliary pump. The opening was a little chewed up where the cast iron rings ride. I just replaced them and didn't want them damaged, so I was going to swap out the pump body with my spare transmission. When I pulled the pump apart I found this under one gear!!! Chunks of ground up metal and a damaged priming valve port - which is part of the top gear circuit!!! I am convinced that this is the problem. Attachments:
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Post by jockduck on Sept 18, 2019 11:09:37 GMT
Hi, I hope you are right, I was thinking about the priming valve in the governor housing, I believe it was a mod only done to 1100/1275 boxes, Certainly early minis don't have it. The photos look yuck, can't think why the damage would occur.
Good Luck
Jock
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Post by steve69aaa on Sept 18, 2019 17:15:50 GMT
I don't know if it is the remains of the tabbed thrust washer. In my books it just says "thrust washer fitted to early units". My spare/older one does not have a thrust washer, so I am thinking mine doesn't get one? How do I know?
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Post by jockduck on Sept 19, 2019 11:29:49 GMT
My mini thrust washer was badly damaged(white metal faced?) and I could not get a replacement, I made a top hat bronze bush to replace the oil feed bush and do the thrust duties. Its still functioning as I know, I'm not sure but I think the later boxes had a top hat bush as standard and no thrust washer. Getting hold the specialized thrust washers for the gear set is getting hard.
Jock
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Post by steve69aaa on Sept 19, 2019 16:19:05 GMT
Yes, Jock. I found a part number on the JPAT website for an APII transmission - a steel and bi-metal one was listed. Not sure if they are available. I did find a brand new gear set and housing on eBay and am going to do that.
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Post by jockduck on Sept 20, 2019 11:47:18 GMT
I have just been through my manuals with no joy, the Jpat drawing lists bimetal(whitemetal faced) for early boxes and steel for later, Your photos show early housings for use with bimetal thrust washer. Yeah! I just found the information the later boxes use an all steel thrust washer with a flanged (top Hat) bronze bush acting as the thrust face, The housings probably are different the later ones having a small recess for the bush flange.
Jock
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Post by steve69aaa on Sept 27, 2019 0:24:53 GMT
Great! Installed the new governor/auxiliary pump and it has never run and shifted better! Finally.  |
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Post by jockduck on Sept 27, 2019 11:10:52 GMT
Well done, you persistence is a lesson to us all. I used to have 3 minis in the family two manuals and one auto I only have the auto left, The auto makes driving interesting waiting for the autobox to do its thing. I think the development of the mini/1100 autobox in the early 60's was a very bold move, autos in small cars is commonplace now but a 4 speed was cutting edge in the 60's
Jock
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Post by notamini on Sept 27, 2019 22:33:50 GMT
Thanks for your persistence. I will be sure to check all of that out when I get around to doing mine.
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