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NV3550 shifting problems (grinding in second and third gear)

GBlackburn

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Good morning everyone. I've been having trouble with grinding of the gears going into second and third. It's much worse if I'm revving up the rpm's accelerating fast. If I take my time shifting and accelerating easy, it's not too bad. I have a 2002 Wrangler with the 4.0L and 5 speed NV 3550 trans. I've even changed the fluid inside and switched to the Royal Purple Synchromaxx fluid. The clutch seems to work fine for all the other gears including reverse. Any ideas? Rebuild or Replace. Would definitely change out the clutch also. Any brands also to recommend? It's pretty much my daily driver with occasional off road use.
 

Chris

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Sounds like you've got some worn synros in need of replacing. If you're already tried the fluids (Redline MT90 is the best stuff to use I hear), then you don't really have another option other than rebuilding / replacing the transmission.

The issue you're describing is fairly common with these transmissions, especially as they get older.

How many miles are on it?
 
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GBlackburn

GBlackburn

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It's got 124,000 miles on it. That's what i was afraid of hearing, but it is what it is.
 

Chris

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It's got 124,000 miles on it. That's what i was afraid of hearing, but it is what it is.
Yep, sounds like it's getting time to have the transmission replaced.

If you do that, do the smart thing and replace it with an AX-15 (which is what most do).

Advanced Adapters (and many others) sells brand new AX-15 transmissions for $1500 and some change. The AX-15 is just as good (if not better) than the NV3550. The NV3550 isn't as common, and costs more to replace.

The AX-15 bolts in place without any issue whatsoever.
 

Mark K

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My 2000 3550 balks sometimes in much the same way and has been rebuilt once. Next time, my plan is to replace with a new AX-15, as Chris suggested.

Point of order on the preferred lubes: my understanding is that RedLine MT90 is what is wanted in the AX-15, but the 3550 wants RedLine MTL SAE 75W80 API GL-4. When my clutch was rebuilt last year, I put the MTL in it and it quickly tamed the worst misbehavior of my 3550.

Y'all please chime in so this is clear (crystal!).
 
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Weeeee

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Yep, sounds like it's getting time to have the transmission replaced.

If you do that, do the smart thing and replace it with an AX-15 (which is what most do).

Advanced Adapters (and many others) sells brand new AX-15 transmissions for $1500 and some change. The AX-15 is just as good (if not better) than the NV3550. The NV3550 isn't as common, and costs more to replace.

The AX-15 bolts in place without any issue whatsoever.
I often see that the Ax-15 is recommended over the 3550, but a rebuilt 3550 can be had for $1000. The 3550 also has a lower first gear so I question why not replace it with a 3550 that is cheaper.
 

fourpointzero

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I often see that the Ax-15 is recommended over the 3550, but a rebuilt 3550 can be had for $1000. The 3550 also has a lower first gear so I question why not replace it with a 3550 that is cheaper.
Because “cheaper” often, as in my case, costs more down the line. Buy new once and you won’t have issues for another 200k miles, or more. Rebuilt is always a toss up.

Thats my experience, thus why I advise as such.
 

Jerry Bransford

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My 2000 3550 balks sometimes in much the same way and has been rebuilt once. Next time, my plan is to replace with a new AX-15, as Chris suggested.

Point of order on the preferred lubes: my understanding is that RedLine MT90 is what is wanted in the AX-15, but the 3550 wants RedLine MTL SAE 75W80 API GL-4. When my clutch was rebuilt last year, I put the MTL in it and it quickly tamed the worst misbehavior of my 3550.
Yep Redline MTL is the correct choice over Redline MT-90 for the NV3550 and NSG370. MT-90 is the right stuff for the AX-5 and AX-15.
 
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Chris

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I often see that the Ax-15 is recommended over the 3550, but a rebuilt 3550 can be had for $1000. The 3550 also has a lower first gear so I question why not replace it with a 3550 that is cheaper.
Where can a rebuilt 3550 be had for $1000? Please post the link.

Also, rebuilt is not the same thing as brand new. That's only as good as the person doing the rebuild and what all they have "rebuilt".
 

bromel

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I wouldn't trust a rebuilt NV3550. The manufacturer is long since out of business and a lot of the available parts are low quality from overseas. For the same money, as others have said, you can get a brand-new AX-15 which should last you for years, and for which quality parts are readily available.
 
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Fader

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I just replaced the fluid in my NV3550 with Redline MTL. It had a tendency to grind a little bit going into 2nd unless you really shifted it hard. After the change to MTL, overalll shifting is a little bit smoother. It still wants to grind a little bit in 2nd, but not nearly as bad as before. The most notable improvement is that the transmission throws off A LOT less heat into the cab, and it no longer sounds like a bag of rocks rolling around in a rock tumbler.
 

bromel

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I just replaced the fluid in my NV3550 with Redline MTL. It had a tendency to grind a little bit going into 2nd unless you really shifted it hard. After the change to MTL, overalll shifting is a little bit smoother. It still wants to grind a little bit in 2nd, but not nearly as bad as before. The most notable improvement is that the transmission throws off A LOT less heat into the cab, and it no longer sounds like a bag of rocks rolling around in a rock tumbler.
I had the exact same experience. A bit of a grind going into 2nd when cold with mopar fluid; now with MTL it will buzz a bit if I shift fast, but much improved, and less "marbles in a can" noise when in neural with the clutch out.
 

Weeeee

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I just simply did a google search for rebuilt NV3550 and came up with a couple of hits for under $1000

Reman or Rebuilt
Xtreme Performance NV3550 Remanufactured $995 +325Core
High Impact T&G 3550 Rebuilt $995 + $350 core

Brand New NV3550
Midwest Transmissions New 3550 $1600 $350 Core

I simply asked the question why the AX-15 over an NV3550, I have seen the threads over the years but never seen hard evidence as to why, just consensus.
BTW I have an NV3550 and I am more curious and looking for options if mine poops out someday. My TJ is currently not driveable but I did drain the trans and water came out. So I am concerned which is why the recent searches.

The thing that bothers me between the AX-15 and the NV3550 is I like the lower first gear in the NV3550(4.01:1 vs. 3.83:1), as I like to play in the rocks. However I have no experience or direct comparison with an AX-15 in my TJ and so I don't know if I would miss it if I replaced it with an AX-15. So it is possible that I am concerned over a non-issue.

Has anyone ever had the NV3550 and swapped in an AX-15 and missed the lower 1st gear?

FYI - I don't care about the cost difference in the oil required for the transmissions, or the noise of the trans as I can't really hear it since my exhaust is a bit loud and dumps directly down under the TJ. :)
 
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fourpointzero

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@Weeeee yes, had the NV3550 and went to the AX15. From my previous negative posts on my experience w the NV, I dont miss it, nor have I noticed the difference in 1st gear.

The difference I have noticed was improved shifting and no noise. Everyone has different experiences w their transmissions, so that’s also up to individual preference.

As Ive also mentioned in another post, I too have bought a remanufactured NV and had a terrible experience. The obvious benefit to buying an Aisin transmission is that parts are readily available, you can buy one brand new w warranty and (some people will hate on me for stating this) it’s made in Japan. And in my experience, I’ve never had any issues w my Japanese cars, Japanese parts or even my Japanese guitars. Yeah, random, I know, but I’ve owned Japanese guitars too. :p

Let me add that Im one to over-think things and with that stated, you may be overthinking your options. End of day, up to you but there’s no negatives to swapping over to the Aisin.
 
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Weeeee

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@Weeeee yes, had the NV3550 and went to the AX15. From my previous negative posts on my experience w the NV, I dont miss it, nor have I noticed the difference in 1st gear.

The difference I have noticed was improved shifting and no noise. Everyone has different experiences w their transmissions, so that’s also up to individual preference.

As Ive also mentioned in another post, I too have bought a remanufactured NV and had a terrible experience. The obvious benefit to buying an Aisin transmission is that parts are readily available, you can buy one brand new w warranty and (some people will hate on me for stating this) it’s made in Japan. And in my experience, I’ve never had any issues w my Japanese cars, Japanese parts or even my Japanese guitars. Yeah, random, I know, but I’ve owned Japanese guitars too. :p

Let me add that Im one to over-think things and with that stated, you may be overthinking your options. End of day, up to you but there’s no negatives to swapping over to the Aisin.
I am always overthinking things, but I am an Engineer so it's part of my make up. Often time we find things on forums and there is no hard evidence just anecdotal, and the outcome is driven by consensus, which is why I questioned the AX-15 choice.

I am not planning to swap mine unless I need too, and the 1st gear ratio is probably what I am hung up on more than anything. I like to sit in 1st gear and just crawl so I don't want to lose that ability. Ultimately I would prefer an atlas T-case, then this would become a non-issue, but but that's not in the cards for now.
 
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jodomcfrodo

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I actually got my rebuilt NV3550 for around $1000 shipped from a place that parts out Jeeps. Only problem I've had is that it pops out of 4th sometimes when decelerating. Otherwise it shifts flawlessly and I'm pretty happy with it. From what the place told me, it was rebuilt with American parts and not the junk from China.

Would I swap an AX-15 in if this transmission goes bad? Probably. Is it a necessity? Not really, at least from what I've seen.
 

chino1969

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Yep Redline MTL is the correct choice over Redline MT-90 for the NV3550 and NSG370. MT-90 is the right stuff for the AX-5 and AX-15.
Damn. I just bought Redline MT-90 for use in my NV3550 trans. and double checked to see I should have used MTL-90. It's already in the trans.. Should I drain and refill with MTL-90 or wait until next drain interval?
 

Jerry Bransford

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Damn. I just bought Redline MT-90 for use in my NV3550 trans. and double checked to see I should have used MTL-90. It's already in the trans.. Should I drain and refill with MTL-90 or wait until next drain interval?
No, it's fine. There's just a very small viscosity difference between MTL and MT-90.