Topic: Decisions Decisions

[DodgeMudder]

My NV3550 is toast it looks like it has been broke since I bought it (there is a pin thats broke off and not in the case) which has let second gear move more when engauged than it's supposed to, causing it to break and take out the syncro assemblies on either side    I looked into rebuilding it but it will cost more for the parts to rebuild mine than to buy a rebuilt one, which is still more than I have to put into my Jeep.

So I have been trying to figure out my next best option, and have decided to use one or two of the '96 Dakotas I have sitting as parts to fix the Jeep. But that decision has left me with more options, so I'm looking for some opinions on comming up with a game plan.

Option one: Take the NV3500 out of the '96 Dak and replace the front case half with the one from the NV3550 in my Jeep and swap that into my Jeep. The biggest thing that worries me about doing this is this whole option is based on the internet rumor that the NV3500 and NV3550 are identical internally and the only difference is the front case halves, with the NV3500 having a non-removable bellhousing, and the NV3550 having a removable bellhousing. This would also let me take the 5.2l out of the '96 Dak and put it into Frogger (my '96 Dak I race at Mud Mushers)to replace the 3.9l.

Option two: Take the entire drivetrain out of the '96 Dak (5.2l, NV3500, 231D) and swap it complete into my Jeep. This is a doable option, but w/ having 4.88 gears and a front locker I could see this easily requiring a change to a different front axle as I don't think the HP30 running either 34ltbs or 36tsls will last long before the shafts start snapping everytime I wheel.

Option three: Take the 3.9l out of Frogger and mate it to the NV3500 out of the '96 Dak (Dodge v6's and v8's use the same bellhousings) and put it into my Jeep, and then out the 5.2l out of the '96 Dak into Frogger. While this is the most work, I do have to at least swap a different tranny into Frogger for next year anyway as the stock one is shot so I'm going to be putting the one in out of the '87 Dakota I have anyway and it won't be much extra work to put the 5.2l in at the same time.

All of these options except one I know I can do, trying the first one envolves pulling and tearing down the NV3500 before I know if it will work and if it doesn't then I just tore down my transmission for nothing. The other two options envolve swapping a different motor in place of my 4 banger, which till this all started I hadn't plan on doing as I like the way my Jeep works on the trails with it.

 

[sharpxmen]

the best solution imo is an AX15 to replace your 3550 from a junkyard (if not a 3550) - i checked car-parts.com and they start at $400 for a 98 TJ 5sp from a 4.0L. you might be able to also negotiate some but the shipping will be extra. If you find one at pick and pull it can be cheaper, so i would do some research locally

replacing engine + tranny will cost you more in the end even if you have them already

taking internals out of the 3500 and put them in the 3550 - if everything goes as planned that can save you some $$$ but i have no idea if it will work or not.

[DodgeMudder]

the best solution imo is an AX15 to replace your 3550 from a junkyard (if not a 3550) - i checked car-parts.com and they start at $400 for a 98 TJ 5sp from a 4.0L. you might be able to also negotiate some but the shipping will be extra. If you find one at pick and pull it can be cheaper, so i would do some research locally

replacing engine + tranny will cost you more in the end even if you have them already

taking internals out of the 3500 and put them in the 3550 - if everything goes as planned that can save you some $$$ but i have no idea if it will work or not.

I don't want to downgrade from my NV3550 to an ax-15, I replaced my Ax-5 3times before decideing to swap in the first place and going down in strength is definately the wrong way to go w/ my Jeep.  I looked into buying a replacement trans first but at $600+ shipping it would be spending too much to end up with a gamble as to it's condition, the NV3550 comming out of my Jeep was used and worked good for 3 years before exploding and when it was torn down I know it had been broke the whole time and it wasn't detectable till it went compltely, most used trans come with a 1 year garuntee or less, so I can just see it turning into being right back where I'm at now in a year.

[sharpxmen]

I don't want to downgrade from my NV3550 to an ax-15, I replaced my Ax-5 3times before decideing to swap in the first place and going down in strength is definately the wrong way to go w/ my Jeep.  I looked into buying a replacement trans first but at $600+ shipping it would be spending too much to end up with a gamble as to it's condition, the NV3550 comming out of my Jeep was used and worked good for 3 years before exploding and when it was torn down I know it had been broke the whole time and it wasn't detectable till it went compltely, most used trans come with a 1 year garuntee or less, so I can just see it turning into being right back where I'm at now in a year.

i think ax-15 is as strong as the 3550, in my case i went with the 3550 as it allowed me to fit the Dana300 behind it w/o much hassle - i think the difference (if i remember correctly) is a shorter 1st gear on the 3550. Anyway, was just a thought, keep us posted with your progress and what route you decided to take.

[dwtaylorpdx]

Stock NV3550 is rated to 300 ft lbs.

I think there is confusion because a lot of guys used the NV3500 to replace AX5's behind their 2.5's due to eh easy bell-housing availability from the 2.5 Dakota. which was a obvious improvement. But eh AX15 is rated for about the same engine packages as the NV3550 except for the NV3550HD which is good to 340 ft lbs.

I think the AX15 is a even swap..

Dave

[Sine Deviance]

The AX-15 is rated about the same as the NV3500. However, the AX-15 has been proven to reliably take much higher outputs countless times. Ratings aren't everything Sometimes it's not about what something was designed to do, but what it can do out of the box.

[dwtaylorpdx]

:) Yep. Or there are things that live up to their rating ,,, Like the AX5.... 

I just wish the AX5 to AX15 was easier... Its a fiddley conversion...

Dave

[sharpxmen]

I just wish the AX5 to AX15 was easier... Its a fiddley conversion...

is not that bad actually - this is what you needto swap the AX5 with an AX15: pilot bushing (to replace the clutch pilot bearing, needs to be about 1/2'' longer), 4 cyl camaro clutch ('86 i believe), '96-'98 4 cyl Dakota bellhousing, longer slave cyl pushrod (or whatever is called) - only external slave though, and the t-case  from the 4.0L which at most wreckers you can trade in with yours + a small fee.

that's it and you're up and running with an AX15. Same for NV3550.

[Jeffy]

I've wondered this but never got a solid answer, why not use a Dakota clutch?

The only downside to an AX-15 is that they have the same cold issues at the AX-5.  (ie. not wanting to shift into 2nd.)

[sharpxmen]

I've wondered this but never got a solid answer, why not use a Dakota clutch?

i didn't look into it, but my guess is that the flywheel and pressure plate are different so you would need those + the clutch disk - this assuming that the starter is compatible with the Dakota flywheel and that the notches for the ECU crank sensor on the flywheel are the same, if they're not then you can't really swap them unless you do some other mods. with the camaro clutch you reuse the stock flywheel and pressure plate but you need the longer pilot and longer slave push rod.

[TrailsLessTaken]

Just a thought here, my motor needs to be rebuilt eventually, if I found a 2.5L dakota with an ax-15 in it, could I just pull the whole drivetrain and drop that in my jeep?  Are the dakota 2.5's any better  than the one that come in a jeep or are they the same exact engine?

[sharpxmen]

Just a thought here, my motor needs to be rebuilt eventually, if I found a 2.5L dakota with an ax-15 in it, could I just pull the whole drivetrain and drop that in my jeep?  Are the dakota 2.5's any better  than the one that come in a jeep or are they the same exact engine?

not sure about the engine (i think they're the same), but the transmission is different so I'm not sure what the challenge is there - is it a 4wd dakota or a 2wd? I believe the output is different between the 2 and dunno if the t-case is the same either in the 4wd. Also the ECU (pcm) is different, so look at the flywheel as well to make sure it's compatible with your PCM (same tooth pattern)

[TrailsLessTaken]

I havent found one yet, I was just curious as I wonder thru junkyards if i found a dakota that was 4x4 that had the 2.5 could i just pull the whole drive train and it bolt in instead of trying to mix and match parts from different vehicles?

[Jeffy]

Dakota AX-15's are clocked a few degrees to the side so they don't sit upright like in the Jeeps.

[TrailsLessTaken]

Do you still run in to that problem when you do the AX-15 conversion in a jeep? or is that just using the ax-15 with the dakota 4cyl