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BANGshift 700R4 rebuild tech part 1

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  • BANGshift 700R4 rebuild tech part 1

    Last month std asked about doing a 700 rebuild for him. I thought it would be a great time for another BANGshift rebuild. So he made arrangements and dropped it off at the shop.
    I got my camera out and finally got time to get busy on it.

    Got started by removing everything on the outside of the case. Front and rear seal, pump bolts, governor, speedo, ect.

    Even being a little extra careful and remove all pressure port plugs. Making sure all contaminated fluid gets washed out.

    Next I flipped it over and took the pan off... Doesn't look good, but I've seen way worse.
    I removed filter and all valve body bolts and somehow forgot to take the pic, but trust me. Remove all valve body bolts then the valve body.

    Now I'm ready to remove the 2-4 servo assembly. Part of the case is broke off around the snap ring groove. But not bad enough to scrap the case. Popped the snap ring out with a small flat blade screwdriver, then tapped around on the nose of the servo cover to loosen it up.

    Notice the light blue O ring once the cover popped out a bit. You can cut it and pull it out to remove the cover. But if you need to re-use the O ring, hook on to it with a 90* scribe and stretch it out. Makes it thin enough to make removing the cover, easier.

    And remove it all from the case.

    If you don't have a pump removal tool, you can most times push the pump out with a flat blade screwdriver. Be careful, don't go ape-shit and destroy the case! Once the pump is removed, you can wiggle the input shaft around and it will push the band anchor plug up. (highlighted with the arrow) Then pull it all the way out. Releases that end of the band. And makes it a bit easier to pull the drums out.

    Here you see pump removed and the ends of the 2-4 band. Remove the band then pull out the drums.

    Band is scorched.. No good.

    Remove the reverse input drum and input drum as an assembly. You'll notice later than the reverse input drum is no good also.

    Must have special tool. 90* snap ring pliers. Here, I already removed the snap ring.

    Now you can pull out the reverse reaction shell and front planet assembly.

    This is the entire front planet assembly.

    Here is the front planet, bearing, ring gear and reaction shaft assembly.

    Very important to check the torrington bearing down inside the front planet. You can't remove it unless you rebuild the planet. This one feels great. Good and smooth.

    Check thrust washers on each side of the pinion gears. These have no wear.

    There is some wear here. A little rough to the fingernail. Maybe can be polished. We'll see later.

    Teeth on the input sun gear are in good shape.

    Bushings on the inside are too.

    This is the reverse reaction sun shell and sun gear assembly.

    Remove the sun gear from the shell and inspect the splines.

    Shells will strip and break around here.

    They can get badly worn and notched out here. This one looks like brand new.

    Rear sun gear is in good shape.

    Next I used my notched out flat blade screwdriver and remove the large snap ring that retains the center support.

    Now you can bump the output shaft forward and it will push the center support out. And remove the output shaft from the rear.

    Here is the center support.

    And the low/reverse clutches that come out.

    The steel plates for the low/reverse clutch have hot spots in them.

    Here you can see someone used a thicker steel plate to remove some clutch clearance. I really don't think it has much benefit unless it was extremely lose.

    Here is the rear planet and ring gear assembly. Same as the front planet. Check the bearing inside the planet and trust washers. Pinion gears should not feel sloppy.

    I removed the low/reverse roller clutch from the center support by removing the highlighted snap ring. Someone has installed a newer center support that uses the wider roller clutch.

    Early style on the right, Later style on the left. You can see the difference.

    Inner race looks to be in good shape. No visible wear or chatter marks.

    Roller clutch looks like new. Rollers are good. No collapsed roller springs.

    This is the low/reverse spring pack and the tool that you need to remove it.

    Engage the tool into the center support lugs in the case. Spin the tool down and collapse the spring pack.

    Use the 90* snap ring pliers and remove the snap ring that retains the spring pack. Here I already have the snap ring removed.

    Unscrew the tool and remove it and spring pack from the case.
    Stand the trans up on it's bell housing. Blow compressed air into this port and it will remove the low/reverse piston.

    The piston falling out will look like this.

    And then I used my exhaust chisels and knocked out the rear case bushing.

    Now setting the empty case aside, I get the reverse input and input drums.

    Lift off the reverse input and set it aside. Notice the torrington bearing on top of the drum. Remove it and the selective washer underneath.

    And cut the four teflon rings off the input shaft.

    Next look into the big end of the drum and remove the thick snap ring to remove the 3-4 clutch.

    Pretty much a burnt 3-4 clutch.

    Now remove the next snap ring. A little smaller in diameter than the last one.

    Now remove the forward clutch, overrun clutch and input sprag assembly. Everything that you see on the rag... More hot spots on the steels.

    Next I disassembled the input sprag by removing the inner snap ring from the bottom of the sprag assembly.

    Notice the arrow pointing at the notch on the left side of the sprag element. When holding the sprag upright, the notch always go to the left. This insures correct sprag rotation.

    Outer race looks good.

    Has the dual cage 29 element sprag which is the best.

    Inner race looks good.

    Another torrington bearing inside the input drum.

    And remove the input shaft to output shaft rubber seal.

    Here is a snap ring that has to be removed to remove all the pistons from the drum. Trans shops has spring compressor that makes it easy.

    Once removed, all this will drop out.

    All spread out, it's going to look like this.

    There is a O ring down inside the drum. Use a scribe and pull it out.

    The reverse input drum has noticeable burn marks.

    Here with a straight edge, you can see daylight. Drum is trashed.

    Again, remove the snap ring from the reverse input drum.

    And all the clutches.. More hot spots.

    Another spring pack and snap ring.

    Everything removed.

    Now the pump. Remove the five pump bolts from the backside.

    Take everything out of the pump body.

    Found a major problem. look at the arrow pointing to wear on the inside of the pump rotor.

    More than likely, the torque converter wasn't engaged into the pump correctly and ruined the pump rotor. Or it could have been a junk torque converter that was too short.

    Pressed the pump bushing out.

    Bushing is wasted.

    New pump is needed from too much wear.

    That about it for part 1 disassembly. Hopefully part 2 will be this weekend. Depends on how much time I get.

  • #2
    Re: BANGshift 700R4 rebuild tech part 1

    Excellent!! :D :D


    • #3
      Re: BANGshift 700R4 rebuild tech part 1

      :o Once again Indy, fantastic pictures and write up. Still makes me go cross eyed looking at all those parts..
      Escaped on a technicality.


      • #4
        Re: BANGshift 700R4 rebuild tech part 1

        A couple suprizes, good and bad. Looking good!
        Cognizant Dissident


        • #5
          Re: BANGshift 700R4 rebuild tech part 1

          Nice work Indy!
          Whiskey for my men ... and beer for their horses!


          • #6
            Re: BANGshift 700R4 rebuild tech part 1

            Thanks Indy...I will be watching!

            Question. What are your thoughts in regards to the TCI constant pressure valve body? I am thinking about trying...just want an expert opinion!


            • #7
              Re: BANGshift 700R4 rebuild tech part 1

              Where was the flux capacitor? :D
              That which you manifest is before you.


              • #8
                Re: BANGshift 700R4 rebuild tech part 1

                Originally posted by Brian Lohnes
                Where was the flux capacitor? :D
                there wasn't one cause it blew up during the time change. ;D


                • #9
                  Re: BANGshift 700R4 rebuild tech part 1

                  Originally posted by CarPlayLB
                  Thanks Indy...I will be watching!

                  Question. What are your thoughts in regards to the TCI constant pressure valve body? I am thinking about trying...just want an expert opinion!
                  I really don't know much about it to be honest. I'm guessing it may be manual shift only? They set the valve body up to have high line pressure all the time. So there would be no tv cable to adjust. Let me know if you try it.


                  • #10
                    Re: BANGshift 700R4 rebuild tech part 1

                    Supposedly the TCI constant pressure valve body will keep you from burning up the tranny due to incorrect TV cable adjustment, but the TV cable is still used to adjust the shift points. The 700r4 I have now seems like it does not respond to changes in TV cable position.
                    My tranny is set up to hydraulically lock the converter above 55MPH...but that is less than ideal. It does not always unlock. When I do a new tranny, I am going to go the old fashioned way and hook up to manifold vacuum and the brake pedal to unlock the converter and allow there a better way?

                    INDY...thanks for this! Trans stuff is VooDoo magic to are impressive...great write up!


                    • #11
                      Re: BANGshift 700R4 rebuild tech part 1

                      What are your thoughts on the full manual valve body for the 700?

                      I have done several gov adjustments (weights and springs) and I have finally resorted to using 2 different govs. One for racing (full throttle shifts @ 6200 and part throttle @ 4300) and a street one that shift @ 2800 for cruising etc. I'm thinking about the manual VB and just shifting all the time....thoughts?
                      Whiskey for my men ... and beer for their horses!


                      • #12
                        Re: BANGshift 700R4 rebuild tech part 1

                        how much ft lb it'll take after the rebuild...
                        as I'm up in the air with od in truck 200r4 700r4 or gearvendor off a th350 or 400


                        • #13
                          Re: BANGshift 700R4 rebuild tech part 1

                          The first time you pull a 700 apart you'll wonder where the bottom of the parts pile is... compared with a 3 spd like a th350 lots more parts...


                          I do have a question though..

                          I have a fully built 2wd 4L70e with the best of factory and aftermarket parts in it except the 300M output shaft. How much torque can I put through this before its gets angry?

                          Currently at about 500 #/ft @ 10 PSI boost... going to turn the wick up shortly.


                          • #14
                            Re: BANGshift 700R4 rebuild tech part 1

                            INDY ROCKS! INDY ROCKS! INDY ROCKS!
                            There's always something new to learn.


                            • #15
                              Re: BANGshift 700R4 rebuild tech part 1

                              Hey Indy I've got a question. It's about my '99 Z28 I had the trany done a year ago, install a TransGo HD2 shift kit, along with the servo's and even replaced the plastic servo pistons in the valvebody with the aluminum pinless type. Plus I installed all new electronics even the main wiring harness and I also installed a 3800rpm stall converter. Anyway everything seems to work right, except one thing, I have my lockup set to engage at 38mph in 4th gear, which it does do, but sometimes it'll lockup and then like a 1/4 of a mile later it'll unlock and not lockup for a maybe another mile. Which then it'll lockup and stay locked up. Also somethings when taking off from a light I can take it up to like 50mph and it won't lock up until I've drive for a 1/2 mile or so. Is this normal operation??, are there other factors in the trany itself that determine when the lockup is suppose to happen or is it just commanded by the computer. I'm just wondering if I might have a faulty lockup solenoid.