NV3550 help

[Mykal]

I dont know much about transmissions. I realize this may be hard to diagnose over the internet. Just trying to figure out where to start.

2000 Jeep Wrangler
Transmission NV 3550

A few weeks ago when shifting into 3rd gear it would grind a little until warmed up.
A week ago it would grind hard going into 2nd gear and sometimes not engage at all.

Two days ago while wheeling/driving I shifted into 2nd gear and it stuck there. The shifter would move from 2nd gear into neutral and left to right but would not shift through the pattern except for 2nd gear.
I drove it to my buddies house and had it towed home tonight.

I managed to get it out of 2nd gear by trying to shift it into first gear.
Now I can shift through the pattern and the gears engage. Except for 2nd gear. It grinds going into 2nd gear and will not seat or engage. If I mess with it enough I can get it to engage 2nd gear.

Master cylinder is full of fluid. No leaks.

I have read the NV3550 has common issues with 2nd gear.

Where do I start? Anyone else go through this?

Anyone swap a AW4 in place of one yet? I have a good AW4 laying around.

[fmlyof4whlrs]

Swapping in an AW4 can be a pain because of all the wiring but should be doable. Probably easier to just rebuild the tranny though. Sounds like sycros are messed up for 2nd gear. I bet if you drain fluid you will find a lot of metal filings. Drop the tranny, you are going to need to anyway. Open it up and start looking around it should become very obvious what is wrong.

[Mykal]

From some of the write ups I have read swapping the AW4 is not a bad job. Clocking the transfercase on it seems to be the worst part.

Ill probably just take it for a rebuild and replace the clutch, throwout, etc at the same time.

[DodgeMudder]

Good look w/ that, I had the internals of second gear explode on my nv3550 that was behind my 4 banger, took out all kinds of good expensive parts, would not go into second gear correctly would grind and make all kinds of fun noises while in second gear and while trying to shift into 3rd or first afte being in second gear. Found out on tear down getting ready for rebuild, that it was going to be $1200 in just parts to fix it. Then I would have to add labor on to it, this is where I stopped found a cheap ax15 tossed it in and called it good enough for now.

[Super Scout]

Yeah I would say keep looking for a used one. Rebuilds are never cheap esp for a failure. It would be different if it just wore out. You hammered it pretty hard when it let loose, than drove it. I have a feeling that tranny is gonna need a lot of work. Either way lemme know if you need a hand.

[gonecheenin]

Never had any serious issues with my AX15's and from reading these threads I'm glad I never found a reasonable NV3550 when I was looking for one a few years back!

[UPJ Wheeler]

My NV3550 also has NO syncro left in 2nd. I picked it up off of your neighbor down there Buggyman... bad move. Once I got home I realized he cut the pilot bearing snub off of the input shaft for the V8 swap he did. I specifically asked him if it shifted ok, because I would have put new syncros in it while I had it apart. He told me it shifted great, so I just swapped the input shaft and threw it in.. I can upshift it without making much noise with a little finesse, but down shifting is a little trickier, always grinds. Now I have to take the whole F'n thing back apart. It's also making a god awful noise intermittently when I engage the clutch, hoping that its just a fluke throw out bearing... If not, I have ALL Of the guts from a parts tranny that I picked up cheap.... Im getting sick of this shit...

[DixieJeeper]

NV3550 is a fairly stout trans and is about as strong if not stronger than an AX15. NV3500 does have 2nd gear synchro issues.

Try draining and filling the trans with new fluid. Use the right stuff! It doesn't take ATF like the AX15 did.

Mopar Manual Transmission Lubricant P/N 4874464
OR
GM Synchromesh Transmission Fluid P/N 12377916
OR
Royal Purple with GM Syncromesh/Mopar Equivelant.

I have fixed a number of AX15 and NV3500 with just simple PM (preventative maintence) Remember a little metal froth or slight film on the magnets is normal.. but if you have alot of froth or lots of chips/chunks or heavy metal froth or debris in it your screwed though. A little is ok... but chunks or large amounts of film is not ok. Escpially brass/bronze debris that would be your syncrhos... big chunks of steel would be your main or secondary shafts, gears, bearings, or blockers= hard parts not common rebuild parts which makes it more major suckage.

[Mykal]

Appreciate it but I dont think thats going to help now. 2nd is there sometimes but 1st, 3rd and Reverse are gone. Something moved around inside there Im pretty sure.

[UPJ Wheeler]

AX15 doesnt take ATF.... factory spec is 75-90W gear oil old chum.... that aside though, I did find a thread that talked about flushing the trans with kerosene. putting a couple quarts in the trans after draining the lube out of it. Put TCase in neutral, start the motor, and run in through the gears at idle for a minute or two. drain and repeat until the cleanser comes out reasonably clean. I'm going to try it tomorrow. Fine particles in the syncros causes too much friction, makes sense to me, and worth a try. I used Royal purple Syncormax in the NV3550 incase anyone was interested. At $15 a qt, its cheaper and probably better engineered than the Mopar stuff at $25 a qt.

Mykal, I do have some NV parts that I may be willing to sell if you get that far with it.... I may want to hang onto them for myself though, not sure....

[gonecheenin]

I can upshift it without making much noise with a little finesse, but down shifting is a little trickier, always grinds. ...

Sounds like the dam NV4500 in my truck - I'm seriously considering selling that on Pirate for a profit & swapping in a good old SM465!

[gonecheenin]

Use the right stuff! It doesn't take ATF like the AX15 did..

If you ran ATF in your AX15 that would possibly explain your lack of faith in it's strength - LOL!

[gonecheenin]

I used Royal purple Syncormax in the NV3550 incase anyone was interested. At $15 a qt, its cheaper and probably better engineered than the Mopar stuff at $25 a qt.

I've been using the Amsoil MTG oil - it's rated for the synchro's in the NV4500 so it's a good low sulfer gear oil for most any trans requiring a 75W-80/90 weight.

[notmYJ]

I just swapped an AW4 into my YJ and would do it again and again. By far the best thing I ever did to it. The wiring isn't bad at all if you are familiar with 12v wiring. I got and used everything from the donor XJ from the flex plate, to shifter. Was pretty straight forward, but I did have a few issues that were due to the YJ being SOA. Nothing a grinder and welder couldn't fix though...

[DixieJeeper]

I ran/run Royal purple ATF in my AX5 and Ax-15s. No problems- ever but perhaps I am just lucky or ignorant.. likey more of the latter. And its likey more of my warm weather climate experence that the gear oil is not thin enough in hot climates. (new to the burgh)... no on second though it is my ignorance.. or is that the beer?

just my two cents I think the AX15/NV3500 are about the same in strength from the rigs I have used and abused them with. I am sure someone knows the gear ratio advantages of one or the other.. I am two busy drinking beer to look it up.

If you have issues with reverse and 1st perhaps its in the reverse idler? I agree with that information its time for some big tear down.

*NOTMYJ love the super35kit signature.. too freaking funny.