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Discussion Starter · #1 ·
I've got a 2.5 w/ the AX-5 tranny. Synchros are on their way out the door, so I'm thinking of swapping in something better.

I know about the SM420 swap which is fine for what I need, but want to know of other ideas. Looking for either manual or auto, but prefer manual.

Trying to get by as cheap as possible, without rebuilding the piece of shit that's already in it. I figure you guys are so hardcore (as opposed to jeepforum.com) that you'll have some interesting ideas.

Tommy
 

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I am putting a sm420 in my cj5. You just can't beat having that granny low gear.
Kory:)
 

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I put a np435 behind my 2.5L. But you used the word cheap in your question. It can't be done "cheap" if your asking. I know I asked and now I'm broke.

Search there is some good info out there.
 

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I've been looking into swap ideas for my 2.5 and i think the sm420 is the way to go. you can also swap in the ax15 the 4.0s use by using a bellhousing from a dodge dakota. can't remember which motor but i know that some of the dakotas ran an AX15 with a bell that'll bolt up to the 2.5

Good Luck in your swap
 

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If you use the AX-15 transmission, you will have to buy a 23 spline input shaft for the T-Case. The AX5 has 21 spline and the AX15 has 23 spline. One note, if you go with the TF-999 TJ automatic from a 2.5L, they have 23 spline outputs to the T-Case, so again, you would have to buy a T-Case input shaft with 23 splines... Just some FYI...
 

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Discussion Starter · #6 ·
Thanks guys! I know it won't be cheap, but I'm very limited on funds (my wife wants a kid) so whatever I do has got to be the best value for my $$.

I knew about the 21 spline vs 23 spline issue, but I think I could pick up a used, stock 23 spline case for a couple bills around here.

I hadn't heard of the AX-15 swap using a Dakota bell housing. I'll have to research the cost issues with it.

Red90YJ - How much did it cost to swap in the 435? Did you do all the work yourself?

Thanks,
Tommy
 

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I swapped both tranny and tcase. With a NP435/205: $350, AA adapter $300, Input shaft $60, custom machining $150, clutch disk $40. Wow that's a $900 right there. I still had to get nuts and bolts, sticks, driveshafts lengthed (I gained 2 inches). Steel for skid plate, assorted fittings, clutch slave I know I'm forgetting a bunch of stuff. Just the junk runs to find a plug to adapt to the backup light cost me $1. I know I could have just pocketed it. But I like doing honost buisness.

No custom swap in cheap. Of course cheap is a relative term. If I kept the 231 tcase it would definitly have cost more. But I still get a better total crawl ration with this than with the original AX5/231.

So far I love except, my wife is very upset because I want a bigger engine. I hope she doesn't realize the money I blew on adapting my current setup.

On the plus side I hope to sell the 21 spline 231 to get back a few dollars.

Except for the machining, Yes I did everything my self.
 

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Discussion Starter · #8 ·
That's not too bad, considering all you did. I figured it would cost about that to swap an SM420, keeping my 231. I just didn't want a bunch of pipe dream suggestions like "put in an NV4500 and Atlas tcase" since that's probably in the neighborhood of $5k. Hell, the divorce wouldn't even cost that much! :D
 

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If you want cheap. Find a np435 from a Ford 4wd and the 205 since you seem to want to keep the driver side drop. A bellhousing from a chevy 2.8 v6 with a manual. Bore the inside of the housing to meet the the 435. Weld one tab on the side of the tranny. Use a clutch disc from a CJ with the 2.5 and your stock pressure plate. Ford throw out bearing and a mean grean starter to clear the housing. $25bellhousing, $250 starter, $200 tranny and transfer, $40 clutch disc. I'm running the SM465 and spent about 300 for the swap. Tranny was free.
 
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