Willys Jeep 4 Speed Swap: Introduction!

Willys Jeep 4 speed swap! It’s time to upgrade from a 3 speed to a 4 speed in the old Willys CJ3B. Deeper gears means a lower crawl ratio and more control on the trails. These swaps have been happening it flat fenders for decades. It will be a lot of time and effort to do this swap but the final result will be worth it all!

[@markpospichal571]

I have thought about this swap for years, so I am really looking forward to watching you do it. Now while you have the tub off makes sense. Thanks for making these great videos!

[@donaldriggs3097]

I thoroughly enjoy your escapades in working on your old Jeep! Keep it up and best of luck with this latest build!!

[@TheOldaz1]

Interesting but logical swap, watching with interest.

[@grannylow7073]

I have 2 flat fenders one with a T-18 and the other with a SM420 and it’s great

[@everydogneedstraining4953]

Thank you!!! Great info!!🎉🎉🎉

[@kenthedenstrom3452]

Here i go again following your for another project on my cj3a. Can't wait to get started. Thank you very much for all your great work

[@stevenredinger9972]

I have used both T-18s and SM420s in Jeeps and PUs. Both worked out fantastic. I also put an SM420 behind a Buick V6 in a Nissan 720 4x4 PU-- again that Grandma gear is very useful. I have run both mated and divorced T-cases. I would collect these transmissions and had a combination of SM420s and T-18s stored in my shed. When living among loggers in Idaho, Dana 20 T cases were eazy to find because Loggers would put FS Ford running gear under their Jeep PUs-- and toss the Jeep gear boxes.

[@6369436]

I like your video's. I have a '81 CJ-5, I think the transmission you are adding is the one I have in my jeep. The best thing about having a jeep is there always to work on,Thank you for sharing the knowledge.

[@LetsBuildaWillysJeep]

Excellent video as usual 👍

[@rrtownsend6432]

Great explanation on ratios. Thanks RT

[@peterbrouwer143]

Looks great. I'm at the start of the same swap for my build. I will post a video as well once complete!

[@xfactorautomotive1496]

Aw, dude!! When I saw the 4-speed swap in the description, I thought you were gonna do the M-21 Muncie swap like I did so you could go racin' people on Friday nights! Haha, I'm just kidding...we are on different ends of the spectrum with what we want to do with our Jeeps. My little dauntless/ M21 is just a street cruiser. I think your idea is great for what you want to do. It's fun researching stuff to swap things into out old CJ's, isn't it!! I love it...keep up the good work Jacob. And you are absolutely right...the tub is off, now is the time to upgrade the trans!! MUCH easier that way.

[@thelarsongarage]

I can't wait to see all the technical stuff with this swap, I think it's cool to mix and match different drivetrain pieces to make the Jeep fit your purpose!

[@sikandarmomin3988]

Very good

[@65cj55]

Interesting.

[@mikep9032]

Oh sure, now you do the 4 speed. I ended putting a SM465 behind the Dauntless V6 in my 67Cj5. It's a little expensive swap but I got a good deal on the trans. Looking forward to you getting hands dirty.

[@davedegan12]

You might check on thecj2apage there is fellow that goes by jpet that has lower gear set than teralow. You have to cut a hole in the transfer case for the large gear.

[@PaulA-yh7kr]

What year and make of truck did the T18 come in. Thank you.

[@miguelcordeiro1023]

Anyone know offhand what size tires are on the orange rims?

[@darreldwalton8763]

So...how long before You unveil plans for a granny low 1st gear, FIVE speed overdrive?...