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post #1 of (permalink) Old 10-15-2002, 11:54 PM
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sm 420 in a YJ?? opinions appreciated

no reverse in the baby buggy.. estimates are around 2k to just repair the peugunk tranny,, a friend of mine suggested doin a swap and putting in an sm 420 w/ a granny low.. my top speed as it is now is 75.. question is.. will i lose my top speed? IF i have a PMS day and decide to put her up for sale will it hinder or benefit to do the swap? (have to drive her to the playgrounds ya know)any advice/experience/opinions are appreciated in regards to the pros/cons...
this girl is kinda frustrated on the whole tranny bit...
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post #2 of (permalink) Old 10-16-2002, 12:28 AM
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Re: sm 420 in a YJ?? opinions appreciated

I don't nessacarily(sp?) think you'll lose your top speed, but probably will be reving the motor pretty high with only 4 gears doing 75mph. Also, do you have an SM420 available already? As I know it, they're becoming harder to find, and harder to find replacement parts for. So keep that in mind. Anything you do in terms of a swap will be MILES ahead of that peugot POS. Just keep in mind you'll need a few adapters, and those run a little bit of $$$. Have you considered a T18, NP435, or SM465? All are great trannies with low first gears. You could also look into doing an AX15 swap or NV3550 swap. Good luck!
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post #3 of (permalink) Old 10-16-2002, 05:43 AM
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Re: sm 420 in a YJ?? opinions appreciated

I would look for a SM465. They are easier to fine, as it has been 35 years since the 420 was made. The 465 has a little better gearing. (less lag between gears) and you still get a low first gear. @ 6.5 with the 465 to a 7.02 to a 420. The adaptors are about the same for the two.
As far as selling it some day. You will be better off with a 4 speed that works than a 5 speed with no reverse.
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post #4 of (permalink) Old 10-17-2002, 07:16 PM
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Re: sm 420 in a YJ?? opinions appreciated

i have considered the t18 and the ax .. as a female i am learning way more about trannys than i ever thought i would have am still in the research stage.. i don't have ALOT of $$$ left in the jeep fund so i am trying to figure out a decent swap that will run 1k or less..i know the adapters alone for the sm420 are barely under that...
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