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How to disassemble black-label overdrive?

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Filigree Avatar
Filigree Silver Member Eric Frazer
Woodinville, WA, USA   USA
1969 MG MGB GT "Mr.Bean"
some pics....

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dickmoritz Avatar
dickmoritz Platinum Member Dick Moritz
Philly 'burbs, PA, USA   USA
Yes, they separate...

Dick



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

Filigree Avatar
Filigree Silver Member Eric Frazer
Woodinville, WA, USA   USA
1969 MG MGB GT "Mr.Bean"
Hi, @dickmoritz, nice to see you here on the forum... Can't send this transmission to you, but would like to. Ironic that I ordered it from PA in the first place. Hell, maybe I bought it from you? Person I bought it from said, "runs great, no issues". But I'm never one to trust internet sales, so I wanted to split the sucker and peek in it. I'm not a professional transmission mechanic, but I've done poo-lenty of transmissions in the past, including 4 automatic transmissions (big ones), and am familiar with being pretty damned fanatical about seals and cleanliness and torque values. I may give this up, but it'd be fun to peek into such old technology and see what the heck was going on back then. I can't remember seeing something so "technical" in a 1960's vehicle before. It's kinda neat.

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Gambit Avatar
Gambit Gareth Goodchild
Indian River, ON, Canada   CAN
Believe me, you don't want to take it apart if you haven't got any experience. Here are a few pics I took when rebuilding my unit under John Twist supervision at one of his workshops. Its pretty daunting. I wouldn't even attempt it and I have done it before. Additionally, it helps to have a full workshop of equipment. Watch John's videos of changing gaskets and cleaning filters etc. they are doable for the handy guy for sure.
Good Luck!


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dickmoritz Avatar
dickmoritz Platinum Member Dick Moritz
Philly 'burbs, PA, USA   USA
Eric, wasn't bought from me; I only offer units I've rebuilt, and only when I can find rebuildable units, which isn't often. Otherwise I rebuild, probably, two overdrives a month for folks, mostly here on the forum, that ship to me either their complete gearbox or just the overdrive unit. I prefer to work only on 4-synchro black label and blue label overdrives because I know them intimately and have parts on hand as needed.

I appreciate that you've rebuilt automatic transmissions, and I respect that experience. But there are a number of traps within these overdrives that can trip you up. I will tell you this, and I'm not making this up. A member of this forum contacted me about his overdrive. He sheepishly told me that his family owned a transmission repair shop, had dismantled his overdrive unit, and concluded that reassembly was beyond their capabilities. He shipped me several boxes of parts which I reassembled into a properly working overdrive gearbox. Perhaps he may even chime in here on the forum to validate this story.

If you choose to disassemble your unit and don't feel comfortable reassembling it, calibrating it, and bench-testing it, feel free to send the parts to me and I'll be happy to put Humpty Dumpty back together again...

Dick




In reply to # 3717936 by Filigree Hi, @dickmoritz, nice to see you here on the forum... Can't send this transmission to you, but would like to. Ironic that I ordered it from PA in the first place. Hell, maybe I bought it from you? Person I bought it from said, "runs great, no issues". But I'm never one to trust internet sales, so I wanted to split the sucker and peek in it. I'm not a professional transmission mechanic, but I've done poo-lenty of transmissions in the past, including 4 automatic transmissions (big ones), and am familiar with being pretty damned fanatical about seals and cleanliness and torque values. I may give this up, but it'd be fun to peek into such old technology and see what the heck was going on back then. I can't remember seeing something so "technical" in a 1960's vehicle before. It's kinda neat.



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

Filigree Avatar
Filigree Silver Member Eric Frazer
Woodinville, WA, USA   USA
1969 MG MGB GT "Mr.Bean"
consider me warned about the dangers of taking it apart. Now then, how does one get those parts to separate? You can see I've removed all the external nuts. What's the trick to get them to separate besides "bang hard" ?

dickmoritz Avatar
dickmoritz Platinum Member Dick Moritz
Philly 'burbs, PA, USA   USA
Never bang hard... winking smiley

You need to remove the overdrive main case from the adapter housing, then disengage the selector lever from the shift forks and withdraw the adapter housing from the gearbox main case. When you remove the overdrive main case you'll probably pull the pump cam away and its indexing ball will escape into the hinterlands.

'course you've probably already gotten the planetary gears out of phase... devil smiley

Dick

In reply to # 3718034 by Filigree consider me warned about the dangers of taking it apart. Now then, how does one get those parts to separate? You can see I've removed all the external nuts. What's the trick to get them to separate besides "bang hard" ?



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

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converse212 Avatar
converse212 Eric Morgan
Atlanta, GA, USA   USA
1958 MG MGA
1970 MG MGB "Daily Driver"
1970 MG MGB GT "Rusty"
1971 MG MGB GT    & more
In reply to # 3718075 by dickmoritz Never bang hard... winking smiley

You need to remove the overdrive main case from the adapter housing, then disengage the selector lever from the shift forks and withdraw the adapter housing from the gearbox main case. When you remove the overdrive main case you'll probably pull the pump cam away and its indexing ball will escape into the hinterlands.

'course you've probably already gotten the planetary gears out of phase... devil smiley

Dick

In reply to # 3718034 by Filigree consider me warned about the dangers of taking it apart. Now then, how does one get those parts to separate? You can see I've removed all the external nuts. What's the trick to get them to separate besides "bang hard" ?

You and phasing, Dick. First its driveshafts, now its planetary gears...what next, the headlights?



Daily driving a '71 MGB

Resurrecting a '58 MGA

riley1489 Avatar
riley1489 Gold Member Bruce H
Great White North, QC, Canada   CAN
1953 Jaguar XK120
1959 Riley 1.5 "King George"
1973 MG MGB
Good luck!



Check your ego Amigo!



Edited 1 time(s). Last edit at 2018-04-17 12:01 PM by riley1489.

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ohlord Avatar
ohlord Gold Member Rob C
North of Seattle, N.W., USA   USA
1957 Land Rover Series I "EYEYIYI"
1971 MG MGB
1971 MG MGB "Bedouin 2"
See post #9

https://www.mgexp.com/phorum/read.php?1,3717591,3717640#msg-3717640



In reply to # 3718543 by riley1489 This is nonsense, I can't believe you guys! confused smiley

Simple diagnostics usually save a headache and cash.

Advice;

Stop trying to separate it and reassemble what you have undone. You need to renew the O rings, gaskets, filter anyway. Then test it to see what it does, these are robust units.

Only if a catastrophic failure occurs consider sending it halfway across a continent for repair.

B



"I'm a long way gone down this wild road I'm on
It's gonna take me where I'm bound
It's a long way around"



"These are the days that must happen to you"

RD2 Radar/ Electronic Warfare Technician
Vietnam 1969-1972

MGB 1976 Avatar
MGB 1976 Silver Member Mark Turechek
North of Boston, MA, USA   USA
1976 MG MGB "The Never Ending Project"
I bought my black label OD on craigslist in an "as-is" condition. I got a really good deal as a result. I was uncertain that it was fully functional, and the seller could not confirm that it was (even though he owned several MGs). He was selling it because he decided he wanted a blue label. I looked into putting it on an engine stand to do the diagnostics per the John Twist Videos: https://www.mgexp.com/phorum/read.php?1,3403640I It nearly flipped over when I hit a rock with one of the caster wheels in my garage. Since I was having my engine rebuilt by Dick Moritz, I decided it would be best to bring the transmission along when I drove out to his area. I wanted to know that it would be reliable and fully functional, because I was skeptical of its condition - but I also didn't want it to become a project/ pile of parts in a box with an open-ended completion date. He disassembled, inspected, repaired and bench tested it for a very fair price. Its in my MG now, and coupled with his fast road engine it is fun. I'm very glad I had Dick take care of it. He has the expertise and experience, and there aren't too many shops/people in the US that have the same specific MGB OD transmission expertise (I think you can count them on one hand).smileys with beer

Filigree Avatar
Filigree Silver Member Eric Frazer
Woodinville, WA, USA   USA
1969 MG MGB GT "Mr.Bean"
Ungh - with due respect, guys, I asked specifically, "how do I take this thing apart". I didn't ask, "who would you recommend on the east coast to rebuild my tranny?", or "do you think this is a good idea"? Unless the thing is spring loaded with a bunch of exploding darts, I'm not afraid of it. I've taken off all the nuts and the damned thing won't separate. I took a chisel to the seam, and now if I don't get it separated to replace the gasket I just now destroyed, it will leak like a sieve.

dickmoritz Avatar
dickmoritz Platinum Member Dick Moritz
Philly 'burbs, PA, USA   USA
Can you post a photo taken from the rear of the gearbox?

Dick



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

Norm Avatar
Norm Norm Davies
NC, USA   USA
1960 MG MGA
1974 MG MGB "Happy Trails"
Eric,

Just saw your PM. My OD is still good 10 years and 9625 miles later. I used a Haynes manual, and lots of web research. To remove the OD from the main transmission, you need to remove the shift 'remote control' housing first, then undo the 8 nuts holding the OD unit onto the housing and it should come right off. Maybe if someone used gasket sealant you may have to lightly tap around with a hammer to get the gasket to break loose. ..very lightly.. Chisels are not required or advised. You should then have the OD unit intact, as shown in the attached pics. When I did mine, I replaced all seals, o-rings, inspected and replaced several bearings, the filter screen/gasket, and the thrust bearing. In the transmission itself I replaced the synchros, at least 1 shim, seals, and I don't remember what else. Probably was overkill in retrospect, but you should at least check it for operation while its out of the car if you don't crack it open. The main bearing in my OD definitely had grit in it. And there was a shim which was busted, and worn synchros in the gearbox itself. How long would it last without failure? A long time probably, especially if you average 1000 miles/year, but my crystal ball isn't working and I don't like strange noises so I went ahead and replaced what needed replacing while it was available.

And pics always help so post some if you get stuck. I took 142 high resolution digital pics during my LH OD rebuild, mainly to help me remember how to put it back together. These were very useful and I recommend you do the same also.

Good luck, let us know what you decide and how it goes smiling smiley


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Filigree Avatar
Filigree Silver Member Eric Frazer
Woodinville, WA, USA   USA
1969 MG MGB GT "Mr.Bean"
Okay! Finally, some traction.

First: If you still have those photos, I'd LOVE to share out a one-drive folder and if you'd be so kind, have you upload some of them. don't need to be "hi-res", they can be medium res. If you don't know how to batch convert hi-res photos to medium, I'd be happy to show you how... (I work at Microsoft Research, I know a thing or two about computers!)

Second: Yeah I took off all those bolts/nuts, and the damned thing won't separate. Yes, the remote control tower too. I'm pretty sure the ding-dong who owned it before me put the damned thing together with GLUE. or silicone. Or some kind of crud. My dad taught me this trick of hammering razor blades into the crack all the way around the transmission in an attempt to get it to separate. I currently have about 8 hammered in there... still no budge-y.

Tarnation.

What you did to your transmission is exactly what I wanted to do: replace the seals, gaskets, synchromeshes, and possibly bearings. I don't want gear whine from my transmission whilst driving, I want to hear the supercharger's whine, not the transmission's or the differential's, or for that matter, the wheel bearings'.

cool. finally found some light at end of stinky oil tunnel. thanks!

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