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  • NV 3550 swap

    Long story short...

    Put a brand new NV 3550 trans in my CJ7 (258ci/D300) and it won't stay in fourth gear? At neutral torque it just pops into neutral. I can also load and unload the drive line and it pops out. It's not the trans - second one. I guess I'm going to pull it out and inspect the pilot bushing and see if it's boogered (fourth gear rides on the input shaft).

    Anybody ever experienced this???

    PS I'm using all AA stuff.

  • #2
    Tower,

    I also purchased evrything I needed for the conversion, including the transmission, from AA. I have not experienced the same problem as you, but a different one. After a few thousand miles my 1st to 2nd and 2nd to 3rd synchros seem to be bad. I have to double clutch to shift smoothly. This started right after I towed the CJ behing my F150. I followed the towing instructions in the original '82 owners manual. In hindsight, maybe I should have found a TJ owners manual to see if the instructions are different for the NV3550.

    Comment


    • #3
      Make sure your flex plate is not all bent and mis-shaped.
      That would do it on the 150/176 trannys I had.

      Comment


      • #4
        Scott82,

        I'm sure you've tried this but a anyway...

        I was experienceing some shift crunch but it went away after I started shifting at a higher rpm (around 2800-3000). I have 4.10 gears in my axle and AA said that the trans is set up to be compatible with the higher TJ gears (3.73 I think???). They said that the trans has a "sweet spot" and I'll need to find it.

        Anywho... The more I think about it - I'm thinkin' it's something with the input shaft or pilot bushing.

        PS Does anybody know the STOCK thickness of the flywheel on a 258ci? I think I may have the wrong flywheel because of some resolved clutch issues.

        Thanks guys, I'll let you know what I find out.

        Comment


        • #5
          Tower,

          I have 4.56 gears in mine. I experience the rough shifting no matter the RPM. I have not heard the NV3550 has a "sweet spot" in the RPM range for shifting. I would think the synchros would eliminate that. Mine shifted OK before I towed it.

          I don't know the thickness of a new flywheel. Did you use the new pilot bushing from AA that came with the transmission? Also did you measure the thickness of the flywheel and trim the release bearing snout if your flywheel was thicker than 1"?

          Comment


          • #6
            When AA told me about the shifting rpms I thought the same thing. I just said, "Okay." It seemed to work for me.

            As far as trimming the snout and all that - hadn't thougt of that.

            I looked at the other NV 3550 that I am sending back to see where the input was wearing and it looked okay. I didn't think to look at the snout. I'll check it tonight. I'm going to pull the trans out this weekend (AGAIN!) and take a closer look at the flywheel and pilot bushing. AA sent me a new bushing so I might just change it out (FYI I did remove the old pilot bushing too). Anyhow, needless to say, back under the Jeep in the dirt.

            Thanks Scott82CJ7!

            I'll keep you posted.

            Comment


            • #7
              It sounds to me like the shift collar is not completely covering the 4th gear teeth. Two possibilities come to mind. 1) Incorrect width front bearing or 2) A bent shift fork.

              I haven't been inside this particular tranny but do you know if there are optionally two different width front bearings available? If so, I would suspect that you have the narrower bearing installed, allowing the input shaft to float back and forth allowing the teeth to slide out from under the shift collar.

              If only one front bearing is available I would suspect the shift fork. You can pull the top cover and check things out.

              Comment


              • #8
                This is my second one and it's brand new - no rebuild. So I'm leaning towards external issues at this point. I was on the phone w/AA for an hour and he called his tranny rebuilder and they both thought the same thing - something with the input shaft. I hear ya on the bearing but I don't remember there being any end play on the input shaft - I'll check.

                Thanks.

                Comment


                • #9
                  Are you saying that the shaft on the transmission where it engages the engine needs to be shortened?

                  Comment


                  • #10
                    Originally posted by tower
                    Scott82,

                    I'm sure you've tried this but a anyway...

                    I was experienceing some shift crunch but it went away after I started shifting at a higher rpm (around 2800-3000). I have 4.10 gears in my axle and AA said that the trans is set up to be compatible with the higher TJ gears (3.73 I think???). They said that the trans has a "sweet spot" and I'll need to find it.

                    Anywho... The more I think about it - I'm thinkin' it's something with the input shaft or pilot bushing.

                    PS Does anybody know the STOCK thickness of the flywheel on a 258ci? I think I may have the wrong flywheel because of some resolved clutch issues.

                    Thanks guys, I'll let you know what I find out.
                    I have one out if you want me to measure.
                    But what do you want me to measure?
                    Diagram would be nice.

                    Comment


                    • #11
                      Thanks Peguin, but I tore into it today and checked EVERYTHING. I replaced the pilot bushing (hydraulic'd it out - very cool), replaced the clutch disk and inspected the flywheel and clutch cover. When I pulled the trans out it was clear where the input shaft was riding - it's perfect. Put it all back together and 4th seems to hold but not by much. It stays without my hand on it and I can't make it pop out unless I barely push on the handle. I'm going to call it good and move forward with the rest of the work. Having an OX put in the rear and finishing some other odds and ends. We'll see how things hold up.

                      Thanks guys for all the help!!!!

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