MCfan Posted September 4, 2015 Share Posted September 4, 2015 Every spring when I leave my 4-speed '70 in Florida and begin driving my '70 SS in Minnesota, I really miss the fun of shifting. I quickly learned that manually shifting my TH400 with the horseshoe shifter was a dicey proposition because there are no lock-outs between neutral and drive and second and low gears. Worst of all, when upshifting from low to second, it is easy to go too far and hit drive or even neutral. I had been thinking about installing a ratchet detent shifter plate in my horseshoe shifter but hadn't gotten around to it yet. When I recently acquired a Thomson Performace DT 4 ratchet detent plate for a 4-speed auto like the TH200 or TH700, I decided to see if I could make my own 3-speed version. It took ten hours and several hand and power tools but I was able to make a 3-speed detent plate out of 1/4" cold rolled steel plate. Since doing it, I would definitely recommend just buying the Thomson Performance DT 3 from Shiftworks for $75 + taxes & shipping (see shiftworks.com). This past Tuesday, I installed my homemade ratchet detent shifter plate in the horseshoe shifter of my '70 Monte Carlo SS454. Now I am shifting my TH400 manually whenever I want with no fear of missing a gear - I love it! As usual, I created a photo journal of the project that is already on Photobucket at this link: Installing a ratchet detent plate Here are a couple of photos from the project to prove it actually happened: 1 Quote Link to comment Share on other sites More sharing options...
7tonemonte Posted September 4, 2015 Share Posted September 4, 2015 I think it's great that you spend the time to document every project Dennis, I know I've followed your pictures before on something. Nice addition to the auto! Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted September 4, 2015 Share Posted September 4, 2015 very nice Dennis!!! I suggest this be saved Quote Link to comment Share on other sites More sharing options...
Bluemalibu Posted September 4, 2015 Share Posted September 4, 2015 Car crafting at its finest, Dennis! Quote Link to comment Share on other sites More sharing options...
mymontesa70 Posted September 4, 2015 Share Posted September 4, 2015 Very nice Dennis. Let me know if you want go on a MN cruise Quote Link to comment Share on other sites More sharing options...
dbreese Posted September 4, 2015 Share Posted September 4, 2015 Great job Dennis! A lot of attention to detail!! Thanks. David Quote Link to comment Share on other sites More sharing options...
footballubet Posted September 5, 2015 Share Posted September 5, 2015 Nice work. So you aren't ready to mass produce these yet? Quote Link to comment Share on other sites More sharing options...
cudax Posted September 5, 2015 Share Posted September 5, 2015 Very nice Dennis, and as always, nice of you to share the knowledge! Quote Link to comment Share on other sites More sharing options...
MCfan Posted September 6, 2015 Author Share Posted September 6, 2015 Thanks for the positive feedback and kind words, guys! I hope the photo journal will inspire some other members to take on this relatively easy and inexpensive project because the results are well worth it. I made my own ratchet detent plate because I enjoy the challenge of fabricating useful items out of metal. I have no intention of making anymore ratchet plates because selling one would probably be a patent violation. Anyone else that wants to make their own can easily download the Patent drawing which gives all the dimensions of the original design and the photos from Shiftworks that show subsequent modifications. I would suggest using 3/16" plate instead of 1/4" plate, which is overkill. I'd be happy to provide additional information to any member who wants to make their own - just send me a PM. However, it is so much easier to just order the Thomson Performance DT 3 plate from Shiftworks so that's what I recommend. Quote Link to comment Share on other sites More sharing options...
black07ss Posted September 9, 2015 Share Posted September 9, 2015 Thank you for the awesome wright up with pictures Dennis. You are a great asset to this club! Quote Link to comment Share on other sites More sharing options...
vince Posted October 6, 2015 Share Posted October 6, 2015 Thanks Dennis this is perfect, you just got me inspired to make one for the 4L60e. 1 Quote Link to comment Share on other sites More sharing options...
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