Understanding the MGB Gearbox Transmission Crossmember Removal, Refitting and Modifications

Understanding the MGB Gearbox Transmission Crossmember Removal and Modifications
A video showing how to remove the gearbox crossmember from the MGB, change the rubber bushes and also some modifications that may make refitting easier. All of the work could easily be carried out at home, please make absolutely certain that you car is secure before working underneath it. A set of axle stands should give you enough room, never work underneath a car that's only supported by a jack. I have added some bookmarks below so you can skip to the section you want.

00:00 Introduction
1:40 Removing the crossmember from the car
06:00 How the crossmember is assembled
08:05 The upper and lower bracket (butterfly plate)
10:00 Changing the rubber bushes
17:35 Crossmember Modification: The advantage of the slotted crossmember
22:49 How I fit the standard crossmember

With any questions don't hesitate to get in touch.

#MGB #Gearbox

[David-wyjl]

Those extra frame holes are used when mounting the crossmember for an overdrive transmission. Installing the x-member for an overdrive transmission is even more difficult due to restricted access. Great video and thanks.

[stephennickles]

You werent kidding David, the bolts into the transmission were engulfed in swollen rubber, what a pain in the neck, but thanks to your video, i knew they were there! The weight of the crossmember was a surprise though, i should have supported that as well as the gear box. Thanks for sharing your experience

[malcolmlane-ley]

David, I can't thank you enough for making me aware of those holes for 'adding lightness'; having them means this job is much easier as you can tighten the mounting nuts through the holes without the need to be a contortionist.

[gavinkidd]

As a MGB owning brit living over here in the USA my ongoing maintenance work has been transformed by using "quickjacks". Gives you more working space under the car, they're portable so ideal for small spaces and safe. Keep up the good work on the MGB videos- superb quality and great technical advice for home mechanics.

[davidsmith]

Awesome video and great tip on slotting out those holes. 2 areas of an MGB I have found that must have been deliberately designed to cause massive frustration: the gearbox crossmember and the windscreen frame and your videos give hope for both 😎

[paulbiegun]

Another well orchestrated video by Mr. Russell-Wilks. Thank you!

[reed-xdzx]

Absolutely spot-on video of how to do this. I will be slotting my crossmember the next time it is off!

[deltafoxtrot]

Great video, thanks 👍. Those gearbox rubber mounting blocks are prone to catching the oil and perish. Mine were like marshmallows allowing then gearbox move about.

[tkreitler]

Thank you David for another excellent how-to video. I appreciate the time you put into these. I'm sure I will refer back to this when I have to pull the transmission. My next project is replacing the exhaust manifold and all the associated gaskets and broken studs. I haven't done this before and am expecting a challenge. Take care!

[sundogstudio]

Once again an excellent explanatory video, David. I have seen a few gearbox removal videos that don't adequately show the mounting arrangement and I was glad to see you show it in detail on the bench. Your videos are always so very well done with meticulous technique which has given me the confidence to tackle the bigger jobs on my own MG. I have plans to swap my 4 speed gearbox for a 5 speed Mazda kit which does not require the use of the original cross member but attaches with a bracket to the frame cross member. Still possibly a challenging job.

[MorroccoM]

Had I not seen this great video I wouldn't have know about the difference when fitting an overdrive transmission. This summer I'm going to pull the drive train from a 1970 B that has an OD tranny and replace it with another 1970 drive train w/o OD transmission.

[brucefraser]

Thank you for that video David. It tempted me to head back under to double check if I’d done everything right but no way! In my case, it’s a 1980 overdrive car. I did it on my back with pretty much everything in situ and it was an absolute bear 🐻 reaching into those little crevices to loosen and tighten bolts. Surely the engineers back in the day could have figured out a better design than that! C’est la vie. Your point re taking care not to strip the threads in the aluminium casing is a very good one. In my case I just could not fit one of the 4 bolts without cross threading it, so I didn’t put it in and drove the car with only three bolts. Looking at it again a month or so later it had shifted to where everything lined up and I was able to put bolt #4 in. So the crossmember gods had mercy on me that day! Great video, thanks again and best of luck on the track!

[rutgergooszen]

Another great video. They are very much appriciated. I replaced all the rubbers a few weeks ago and I managed to remove the four bolts in the gearbox from under the car without having to lower the gearbox (held in place by a lift), with normal spanners. My biggest challenge, as you show, is to put the rubber grommets in the butterfly. Then I built it all up off the car and replaced the hole piece using a second lift under the crossmember to align the holes with the bolts into the gearbox. A bit fiddly but possible. But again I have no overdrive.

[bshnabel]

Absolutely excellent detailed video, thank you

[oliverscott]

Hi David Another great video. Precise and concise. Your car is so well maintained. I was wondering what you use to seal underneath your MG. Is it just painted??? I was thinking of using the black sealant (liquid tar) that they use to fix holes in roof gutters, etc... Any thoughts????

[davelinkson]

Great video!
Had my gearbox and crossmember removed and found the butterfly assy missing, so have to replace it.
What significance does this part have, I'm assuming it takes stress off the mountings coming through the transmission?
Thanks..

[SM-xmdt]

David, do you ever use poly bushings?

[chrispatterson]

Hello David,
What is the diameter of the holes in your crossmember?
Thank you.