My Dakota has a really bad rod knock, and i am thinking of swapping the current V6 for the 318, but I dont know if my current transmission will bolt up. Nor do i know if the AX15 will handle the horsepower/torque coming from a modified V8. Should i just get another 3.9 and modify that? Or should i attempt a 318 swap and hope for the best? I really dont feel like putting a new transmission in my truck. any help would be appreciated.

Thanks!

 

THe 318 will bolt right up to your original trans.

 

and you have the NV 3500, not a AX-15.

 

V-8 all day every day. the v-6 sux

 

Everything I have read says the manual V6 in 99 came with the AX-15 transmission. they started putting the NV3500 on the V6 in 2000. Thats why I am worried about it. Any references to this would be appreciated.

Would an AX15 hold up to 300WHP from a V8?

And I want to put a new rear end in my truck, to lower the RPM's at highway speeds. It currently sits at 3000 in 5th gear at 80MPH, and i would like to lower that to 2500RPM to save a bit of gas. Any suggestions?

 

first you need to determine what gears you have now. Sticker in the glove box. Then search online for some speed/gear calculators and you can play with that til you find a gear ratio you will be happy with.

oh and allpar.com can answer the trans question.

 

ANybody know how much a new NV3500/3550 would cost?

 

Just looked on ebay the other day they are going for 800-1,500 depending on who is selling them and if they are refurbished. Also I can go to the junk yard here but I have to pull it myself but they still only charge 150.00 for a tranny no guarrentee it will be perfect but it will work.

 

No, the AX-15 does not have the input torque handling ability to stand behind the 318 for long. There is a reason why Dodge didn't put it behind the v8! Even the v6 Rams all have the nv3500 behind them because of the weight of the trucks. Its not a very strong transmission at all. It may work for a while, but why not sell it while its working to get some money for it rather than wait for it to blow up and have to replace it!

 

A lot of that is your engine/tranny combination. I wouldn't worry about gears until the engine and trans have been swapped out. The NV3500 has different gear ratios than the AX15. If you go with a higher gear (lower numerically) it will hurt your acceleration.

If you're really looking to lower that cruising RPM, a slightly taller tire will effectively raise you gear ratio make your cruising RPMs lower, but it may cost you some mileage around town.

HTH

- miggity