Hi there, i have blown up 2 gearboxes during few years. Yesterday was the day when i wanted to see what happened inside.
Tryed to google some images how to disassemble gearbox but i found only few low quality pics. This is not a DIY how to disassemble the gearbox but i have lots of hi res pics.
Lets hope they will be useful to somebody. To be hones, its quite easy to disassemble the gearbox, locking pin is only PITA thing and when assembling you have to have shift rods in right position.
First one blew up when i was accelerating and diff blew up and got stuck for a second.
Second one blew up while full accelerating with 2.nd gear, i dont know was it engaged then completely. I have heard rumors that it is one weak spot for getrags that 2.nd gear does not engage sometimes "correctly". I have noticed sometimes even when driving normally when you pop out 2.nd gear that it is littlebit "harsh". Hard to explain
Can you specify more details on how to resassemble the tail casing? You say that the shift rods need to be in the "right" position, but what does this mean? Also, I'll ask the same about the locking pin. My spare 420g is in great shape, but the tail housing has a crack in it. I have a new housing to put on, but have been apprehensive about taking the casing off for fear that I won't be able to put it back together correctly. The pictures are great, but a bit more narrative would be great. Thanks!
Also, if you have a spare output flange and shims, I would be interested in them. I used my v8 output flange on my M3 6-speed when I put it in my 530i, so to make my spare transmission complete again, I need another v8 flange.
Ok, Ill try todo somesort of writeup in a few days when i have time.
Lost compression two days ago from my car(cyl6 and 7) so iam quite busy now with that thing.
I think i will find something extra inside my engine.
Thanks for the photos and time you took to take them. I'm always bad about that.
Hopefully you were ok when the diff "blew up?" I had one do that to me while on the interstate. I was going about 60mph and started hearing a noise. I did my best to get over 3 lanes to the shoulder. Well, I nearly made it and then the stuff movies are made of happened! The whole rear locked up, I went sideways, slowly looked in the rearview expecting to be rear-ended, all the while steering to avoid the guard rail. At the very last moment, I came to rest and nothing was harmed! I immediately called for a rollback and gladly paid that guy $100+ as my day could have been MUCH worse!
The biggest pain was swapping the rear out and getting to all the axle bolts because the wheels would hardly move.
Very cool stuff here. Will the mystery of DIY'ing the 420 finally be solved? Are all the fancy tools and presses just a bunch of bull? Sub'd for more details. Good work burnout.
I didnt have any fancy special tools. Regular mm socket and wrenches. Couple screwdrivers. Ok...if you want to remove gears etc then you have to have somesort special tools.
But this project is on hold now beacause i discovered today that my block is melted between cyl 6 and 7. :frown
Where is it leaking? Between middle casing there is not any seals, metal to metal. Then in front of the gearbox and at the end you have seals but you can replace rear one without tearing it apart.
PS: Do you have any S62 blocks lying around? Would need one!
Most recent project was the case swap so I could install the low mileage transmission into my car. I replaced the front seal, fork bushing and throwout bearing guide bushing. The "new" transmission already had the updated detent kit. I also used a thin layer of RTV on the case joints as leaks are sometimes heard of. There is no gasket between the case pieces. This work took like 8 hours because I had to fight and curse the shaft pins to align so I could get the rear cases off.
Pyite,
The reality is that none of the key internal parts (bearings, synchros) are currently available, so not sure how parts may become more difficult to find. The parts that BMW currently sells (shifter balls/springs) don't generally wear out on the newer boxes and as such I don't see a significant demand for these. The only option that will be available is a used box (a gamble) or a rebuilt one from BMW/Getrag. The latter currently costs ~$4.5k, but is likely to go up in price over time. I doubt many (if any) people are going to go and buy a rebuild box now and keep it in their garage for if/when they may need it.
In the racing world, the price of aftermarket transmissions is coming down while the cost of rebuilt OEM trannies is going up. Makes the choice an interesting one. My current project is trying to mate a ZF 5-speed (stronger synchros and much lighter) with the S62.
You are a good man to decide to replace the sleeve that the throw-out bearing slides on. I chased hard shifts into 2nd gear for 2 years. I had the detent pins replaced, as well as almost every part of the drive line. It turned out in the end of the day the throw-out bearing was not sliding well on the sleeve and was preventing the clutch from fully disengaging. I had replaced the clutch and throw-out bearing but not he sleeve.
After that my transmission shifted as smooth as any new car. Never a crunch into 2nd even on the 10 degree mornings, it was absolute bliss. Still had to shift slow on the cold days though to warm it up, it was still stiff.
If you're going to go through all the trouble to reseal a trans for leaking between the sections (I did, with the help of a technician friend) at least use anaerobic gasket maker when putting it all back together to ensure it won't leak again!
M3Augy,
Interesting for you to mention this. About 2 years ago I actually emailed Permatex customer support and asked am this exact question. See below for the email stream and their response. At least in 2017 they seem to favor Ultra Grey.
From: Boris Sent: Sunday, November 26, 2017 12:31 AM To: Product Application <ProductApplication@Permatex.com> Subject: New submission from Permatex.com - contact Us - Product App
Message: Hello,
I would like to get your recommendation for sealant. Specifically, I am sealing a manual transmission case that will be used with ATF fluid. I don't care about the convenience of a fast drying time because it will be at least several weeks from the time I put the transmission together until I install it into the car and add fluid. Most important to me is long-term seal without leaks.
Thanks, I'll go with that. I was just curious what are the pro/cons of using an anaerobic sealant instead? Some guys on the forums claim good results for sealing aluminum manual transmission cases with anaerobic sealants.
Hey technician117,
A few questions for you. First, I am curious how you pulled off the countershaft gear. What kind of press did you use and did you have to heat the gear to get it off? Also, were you able to put it back on? Lastly, what is the black material that is clearly destroyed in the '559 picture? Looks like some plastic retainer of some sort was shredded.
That trans was run without oil, melting anything made of plastic and turning what remaining oil there was into metal soup. I got it to use the rear case for another trans I got at the same time that had the rear case broken in shipping.
I haven't done much else with these since back then. Projects like that are far to low on the priority scale, especially with a couple companies (at least one) rebuilding them. Not worth my effort. I still have a decent amount of parts which is nice for future repairs to things that are more easily accomplished.
Dan's Diff's Online does them. Not sure who else does it "commercially". Re-reading this thread, I still have the same sentiment now: These are readily available enough on the used market for fair prices that unless you have a specific goal (racing application), it doesn't make sense to commission a rebuild. I suppose if someone is well off enough and they don't care about the cost versus having a "new" transmission, then this is definitely the way to go. AFAIR, BMW no longer sells new 420g's.
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
BMW M5 Forum and M6 Forums
3.2M posts
125.8K members
Since 2000
M5Board is the best forum community for information on the BMW M5 E60 (V-10), E39 (V-8), E34 (straight 6), E28, F90 and F10. Discuss performance, specs, reviews and more!