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    Gearbox removal

    Hi,
    Sorry, but I can see I might be piling in with a few questions on this little project. I have had a look through the forum but can't find an answer to this one. (even Braynester's epic, (what happened with him and his Stag?))
    The manual says to loosen the top 5 bell housing bolts. Is it OK to remove them altogether while the car is on the floor and they are accessible? I'm intending to do the job on a scissor lift with a borrowed transmission support jack and don't want to have to lower the car right down to remove the top bolts then have to lift it up again. Or is it OK to do the lowering and lifting once the gearbox is resting on the subframe. Or is my approach wrong and would it be better to do it keeping the car close to the floor and using a trolley jack? I don't want to run the risk of bending the first motion shaft.
    Thanks again as usual, don't know where I'd be without all the info on here. Although sometimes the topics raise more questions)
    Mark.

    #2
    Remove the top bolts completely.
    Provided the gearbox is supported at the rear end, the engine and gearbox will not move out of alignment until the last bolt is removed.
    The last bolt should be one of the two nearest the bottom of the bell housing. I always place some kind of support under the back of the engine before slackening the last bolt as the engine will drop backwards due to the mounts being towards the front of the engine.
    Some sort of jack is best for this as it will be necessary to allow the engine to lean back to get the back of the box out from the under the box section that runs around the transmission tunnel.

    After many years of struggling with various gearbox removals and refitments, I have finally made an attachment for the top of my trolley jack on which I can balance the gearbox. This is especially useful when replacing the box
    Neil
    Neil
    TV8, efi, fast road cams and home built manifolds. 246bhp 220lbft torque

    Comment


      #3
      Thanks again Neil,
      I think that's the way I'll do it. Seems the way to go by using a trolley jack and support with the engine and gearbox closer to the floor than having the car right up in the air and using a tall vertical telescopic transmission jack.

      Comment


        #4
        Originally posted by Markvh View Post
        Thanks again Neil,
        I think that's the way I'll do it. Seems the way to go by using a trolley jack and support with the engine and gearbox closer to the floor than having the car right up in the air and using a tall vertical telescopic transmission jack.
        Having done the job both the ways you suggest, the last time a couple of months ago using the Scissor lift and transmission jack, I would definitely use the scissor lift again. Perhaps you are much stronger than me but I found it much easier to pull the box off while sitting on a 'hop up' directly underneath than lying down and pulling with both arms above my head. If you use the scissor lift /Tranny jack just make sure you can position the jack where you need it as unless you have the car in the right place the jack legs will foul the lift when you try to get the jack under the balance point of the box. - Alan

        Comment


          #5
          Not sure here and I don't want to upset people but am I correct in saying you still need to raise the car on ramps to obtain access to the top bell housing bolts with a number of 3/8 extensions and universal joints. I have found that doing the job single handed that the top bell housing nuts can be retained using a broad bladed screwdriver between the nut and bell housing rather than a spanner
          John
          1978 Stag Brooklands Green

          Comment


            #6
            Originally posted by alan_thomas View Post

            Having done the job both the ways you suggest, the last time a couple of months ago using the Scissor lift and transmission jack, I would definitely use the scissor lift again. Perhaps you are much stronger than me but I found it much easier to pull the box off while sitting on a 'hop up' directly underneath than lying down and pulling with both arms above my head. If you use the scissor lift /Tranny jack just make sure you can position the jack where you need it as unless you have the car in the right place the jack legs will foul the lift when you try to get the jack under the balance point of the box. - Alan
            Hi Alan, I know you are much stronger than me, the way you moved that scissor lift about to get it in to your van!
            Using a tall telescopic transmission jack, I am also worried that I won't get the right balance point to sit the gearbox and overdrive onto the cradle.
            Thanks,
            Mark

            Comment


              #7
              Originally posted by Markvh View Post

              Hi Alan, I know you are much stronger than me, the way you moved that scissor lift about to get it in to your van!
              Using a tall telescopic transmission jack, I am also worried that I won't get the right balance point to sit the gearbox and overdrive onto the cradle.
              Thanks,
              Mark
              I didn't recognise you from your forum name. You will be glad to know the lift is working well and i'm keeping it busy! - Alan

              Comment


                #8
                Originally posted by JOHNS View Post
                Not sure here and I don't want to upset people but am I correct in saying you still need to raise the car on ramps to obtain access to the top bell housing bolts with a number of 3/8 extensions and universal joints. I have found that doing the job single handed that the top bell housing nuts can be retained using a broad bladed screwdriver between the nut and bell housing rather than a spanner
                That's pretty much what I did today when removing the uppermost bolts. It doesn't take much to hold the nut once the have been cracked.

                Comment


                  #9
                  Hi,
                  I've got all the uppermost bellhousing bolts off today (one top one was missing). I've removed the nearside front pipe. I'm hoping to leave the offside front pipe on. I've removed the propshaft bolts, which actually proved to be the hardest job of all so far to do physically. I even had to remove a grease nipple from the UJ to get the bolt out of the flange. I've blocked the prop up as high as it can go up to the underside of the floor and there is a 30mm gap between the flange faces. Is this enough to pull the gearbox out when it is lowered on the support jack when I remove the gearbox mounting support plate and bellhousing lower bolts? Ive just got 6 bottom bolts in the bellhousing to remove when everything is ready.
                  I notice in the Stag Parts Catalogue that the bellhousing spring washers appear to go under the bolt head and not under the nut. The catalogue doesn't show any washers under the nuts. Is this all correct?
                  Hope that makes sense! Thanks very much.
                  Mark
                  Last edited by Markvh; 6th January 2020, 20:35.

                  Comment


                    #10
                    Originally posted by JOHNS View Post
                    Not sure here and I don't want to upset people but am I correct in saying you still need to raise the car on ramps to obtain access to the top bell housing bolts with a number of 3/8 extensions and universal joints. I have found that doing the job single handed that the top bell housing nuts can be retained using a broad bladed screwdriver between the nut and bell housing rather than a spanner
                    I should have said "between the nut and the engine adaptor plate" not the bell housing.
                    John
                    1978 Stag Brooklands Green

                    Comment


                      #11
                      Originally posted by Markvh View Post
                      Hi,
                      I've got all the uppermost bellhousing bolts off today (one top one was missing). I've removed the nearside front pipe. I'm hoping to leave the offside front pipe on. I've removed the propshaft bolts, which actually proved to be the hardest job of all so far to do physically. I even had to remove a grease nipple from the UJ to get the bolt out of the flange. I've blocked the prop up as high as it can go up to the underside of the floor and there is a 30mm gap between the flange faces. Is this enough to pull the gearbox out when it is lowered on the support jack when I remove the gearbox mounting support plate and bellhousing lower bolts? Ive just got 6 bottom bolts in the bellhousing to remove when everything is ready.
                      I notice in the Stag Parts Catalogue that the bellhousing spring washers appear to go under the bolt head and not under the nut. The catalogue doesn't show any washers under the nuts. Is this all correct?
                      Hope that makes sense! Thanks very much.
                      Mark
                      Don't think it makes any difference. See below

                      Split washer or spring lock washer Grower01.jpg A ring split at one point and bent into a helical shape. This causes the washer to exert a spring force between the fastener's head and the substrate, which maintains the washer hard against the substrate and the bolt thread hard against the nut or substrate thread, creating more friction and resistance to rotation. Applicable standards are ASME B18.21.1, DIN 127 B, and United States Military Standard NASM 35338 (formerly MS 35338 and AN-935).[12]
                      Spring washers are a left hand helix and allow the thread to be tightened in a right hand direction only, i.e. a clockwise direction. When a left hand turning motion is applied, the raised edge bites into the underside of the bolt or nut and the part that it is bolted to, thus resisting turning. Therefore, spring washers are ineffective on left hand threads and hardened surfaces[citation needed]. Also, they are not to be used in conjunction with a flat washer under the spring washer, as this isolates the spring washer from biting into the component that will resist turning.

                      The use and effectiveness of spring lock washers has been in debate of late, with some publications[13][who?]advising against their use on the grounds that, when tight, the washer is flat against the substrate and gives no more resistance to rotation than a normal washer at the same torque. NASA researchers have gone as far as to say "In summary, a lockwasher of this type is useless for locking."[9][14] However, a spring washer will continue to hold the bolt against the substrate and maintain friction when loosened slightly, whereas a plain washer will not.[b]

                      The benefit of spring lock washers lies in the trapezoidal shape of the washer. When compressed to loads near the proof strength of the bolt, it will twist and flatten. This reduces the spring rate of the bolted joint which allows it to maintain more force under the same vibration levels. This prevents loosening
                      John
                      1978 Stag Brooklands Green

                      Comment


                        #12
                        Hi Mark have you only unbolted the front flange of the propshaft, I don’t think you will have enough room , I took the rear mounting of and could take the prop out with my exhaust but if it won’t come out you can push it back over the axle casing, also it will be a lot easier if you take the other exhaust off as well
                        david

                        Comment


                          #13
                          Another question I’m afraid. Approximately, how far does the face of the bell housing come away from the face of the flywheel housing on a manual with o/d or the clutch assembly before it is free?
                          Thanks again.
                          Mark.

                          Comment


                            #14
                            Probably about 3 inches to disengage the clutch splines from the plate and allow the back of the box to drop relative to the engine but about 5-6 inches until the end of the input shaft clears the clutch cover.
                            Neil
                            TV8, efi, fast road cams and home built manifolds. 246bhp 220lbft torque

                            Comment


                              #15
                              Another quick question! Are the engine to gear box anti vibration straps the ones that fix to the side of the sump? If so, why do you have to remove the nuts securing them? They appear to be fixed to the flywheel housing.
                              I’ve removed the gearbox support and lowered the box on a jack but the bottom of the sump won’t come down far enough to sit on the sub frame. Is this OK? I disconnected the top hose but not the hoses to the heater unit.
                              Last time I was this nervous was before I went in for my vasectomy!
                              Thanks again. Mark.

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