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Hey guys, I just got done converting my girl's '02 GT from manual to auto. I used a 4R70W out of an 28k mile '03 Mach 1. I also got the converter from the same car, but I had it sent out and re-stalled to about 2800rpm (I told him I wanted it to stall @ 3k when supercharged making 400rwhp). Before I installed the trans, I did the revised 4R70W J-Mod off of TCCOA: Pretty simple, take out the 1-2 and the 2-3 accumulator springs, and drill out a few holes in the separator plate. So I did that and installed it yesterday using a Baumann TCS. I'm still in the process of fine tuning the shift points. The 1-2 is neck snapping, and the 2-3 is slightly firmer than I would like. Right now the car is stock with only the stall converter, J-Modded trans, and O/R h-pipe. I'm thinking about throwing the accumulator springs back in. If that isn't to my liking, I was going to get a Baumann shift kit. The only problem with that is that the holes might be drilled too large in the separator plate and Ford tells me thats only sold with the valve body. Anybody have any experience they can offer? I was hoping the J-Mod would be amazing since everybody raves about it, but I'm less than impressed. Thanks!
Hey guys, I just got done converting my girl's '02 GT from manual to auto. I used a 4R70W out of an 28k mile '03 Mach 1. I also got the converter from the same car, but I had it sent out and re-stalled to about 2800rpm (I told him I wanted it to stall @ 3k when supercharged making 400rwhp). Before I installed the trans, I did the revised 4R70W J-Mod off of TCCOA: Pretty simple, take out the 1-2 and the 2-3 accumulator springs, and drill out a few holes in the separator plate. So I did that and installed it yesterday using a Baumann TCS. I'm still in the process of fine tuning the shift points. The 1-2 is neck snapping, and the 2-3 is slightly firmer than I would like. Right now the car is stock with only the stall converter, J-Modded trans, and O/R h-pipe. I'm thinking about throwing the accumulator springs back in. If that isn't to my liking, I was going to get a Baumann shift kit. The only problem with that is that the holes might be drilled too large in the separator plate and Ford tells me thats only sold with the valve body. Anybody have any experience they can offer? I was hoping the J-Mod would be amazing since everybody raves about it, but I'm less than impressed. Thanks!
bikewiz: You should leave the 1-2 springs (top, bottom) IN. It will be very firm without the bottom spring. The bottom 2-3 spring should be OUT. [Just driving around town, I could tell the shifts were quicker but they were NOT harsh and I drilled for "300 hp/mild"]. Are you sure that you did not make the holes bigger than required? If you drilled for the supercharger future power level but are still N/A then the holes are really a bit big for the current power level and will be too firm. Does the Baumann TCS let you reduce shift pressures? There are a lot of transmission parameters that can be tweaked (I use SCT's ProRacer software) like pressure, lockup rate, unlock rate, pressure rates (ramping up, ramping down), etc., to get the shifts like you want them. The separator plate is not sold separately, as you found out. You can buy a new valve body but it's about $300. You can fill in the drilled holes with brass (beat it in there, then make sure the surface is made flush with the plate) and then re-drill with a smaller bit. I can't remember where I saw the thread about this nifty fix but it is reputed to be "good as new" as a repair method. The J-mod is really the best way to go for the 4R70W, imo. Get those 1-2 springs back in and test drive. Check TCCoA.com Technical Articles/Transmissions/"transmissions 101" for the drill sizes recommended for various power levels.
If you click the link that I provided to the PDF, you can see the exact instructions I followed. This is what it said on the first page: Ignore what the article says and do this... Remove the bottom 1-2 accumulator spring and remove the bottom 2-3 accumulator spring. For holes do this. Hole #2 is the intermediate clutch feed (1-2 shift). Make this hole in the .100"-.110" range. It should be .081" in your plate right now. Hole #10 is the reverse clutch feed. Totally optional. If you want it to engage into reverse faster when you move the lever, open this up to .093". Holes #4 & 5 are the direct clutch feed (2-3 shift). Open both of these holes up to .100"-.110". Holes #9 and 11 are the forward clutch feed (4-3/4-2 shift). Make both of these .100-.110" as well. So I removed the bottom 1-2 and the bottom 2-3 springs. I will definately put the 1-2 spring back in. Based on my hole sizes, should I put the 2-3 spring back in? Know of any place I can just find a weaker/shorter spring?
When I did mine I removed the 1-2 and 2-3 accumulator springs also and under light/moderate throttle the 1-2 is a little on the harsh side. When I change the fluid the next time I'm putting the 1-2 spring back in. My 2-3 is ok. I'd put the 1-2 spring back in and depending on how the 2-3 is maybe try to fine tune it with the TCS.
I think you are right on the money. I drove the car again this evening and it only seems to be the 1-2 shift that is brutal. The 2-3 is still overly abrupt and firm, but I think that will be necessary for durability when the supercharger finds its home under the hood next year. I'm just gonna throw the 1-2 spring back in tomorrow and see how that goes. Thanks!
I know some tuners also let you play with the line pressures which will allow you to soften or firm up shifts. I did the j-mod in my 01 and love it, nothing harsh at all, I almost wish mine was a little stronger. What did you do with all your manaul trans stuff? I would be interested in swapping mine to a stick.
I still have everything for the manual trans. Sitting on it for the moment, but it will be for sale shortly. Just gotta do some research to see what my asking price should be. I can adjust the line pressure via the TCS based on throttle postition, but I'm wary of lowering the line pressure as I don't want to create any slippage. Im new to programming with the TCS, so I'd prefer to leave line pressure where they have it set. I'm gonna toss the 1-2 and the 2-3 springs back in tomorrow and see where that gets me. Thanks for the advice!
Well, I put the 1-2 spring back in. I wasn't confident that the 1-2 would be firm enough after putting the spring back in. I happened to find a 1/4" spacer the exact diameter of the spring in my tool box. I tossed the spring back in, stacked with the 1/4" spacer. This worked out perfect! All the shifts are firm and precise, but not jolting. I'm very happy with it now. Thanks for the help!
bikewiz: I tried to post yesterday but kept getting a "connection failed" message. Anyway, here is what I tried to post: _Yes, I did read the PDF and the holes (0.100 to 0.110") are generally sized for the "300 hp w/gears" and/or the "300-450 hp" levels. For the stock engine and without gears, I think that these will be a bit large so the shifts will be firmer than you like. I agree that putting the springs back in will still give you quick shifts without jarring your teeth. When the supercharger goes in, you can take out the 2-3 spring. I still think you will prefer the 1-2 spring left in but that's up to you. Please post back with an update (i.e.--how do the shifts feel with the springs backin)._ Sounds like things are shifting just like you want so all is well. Good work! Thanks for posting an update, too.
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