NV3550 transmission grinds into third gear

[KingCarGuyZ]

Received the Redline MTL and ended up making the switch today. Didn't make a difference in my case sadly. I am able to shift smoothly through all gears if I shift relatively early but as soon as I up the rpms to about 3k or above it'll grind into third and only third. Also grinds if I try to downshift into 3rd. It does not pop out of the gear or anything else.
I am not aggressively driving the car when this happens.
This jeep only has 87k miles but it looks like my synchro might be going out in that gear. Guess it was just a coincidence that it occurred all of a sudden when I changed the trans oil. Im going to start saving up for a possible new trans.
Thank you guys for your help.

Give the MTL a few thousand before you pull the trans, mine didint do much the night I swapped it, but was loads better after about 1,000 miles

Does this problem get any better or worse with trans temp?

 

[ToeKnee217]

You should be able to bang shift the transmission at redline without grinding. The trans may not shift smoothly, but it should not grind. Not recommended to do so, but a trans with properly function synchros shouldn't grind.

Most likely your synchro is going out. I drove around with busted synchros on every gear besides 5th for a year+. You have to learn to match the speed when upshifting and rev match downshift. On downshifts, I usually just push to neutral, rev to the correct speed, clutch in, and then push into gear. Keeps everything smooth even when I essentially had no synchros. If you give the synchros no work to do by matching speeds, whether they are there or not does not matter.

I ended up swapping my NV3550 since I was moving to the city and no synchro driving in traffic just doesn't work well. If you end up swapping the transmission, get it from somewhere reputable. I ordered mine from JeepsUnlimited in Colorado and it is not a good transmission. Pops out of 4th on deceleration and pops out of second in 4low.

Yeah im quite adept at rev matching as my previous daily was a 5 speed tremec trans that I had for 8 years in my mustang. Its definitely drivable as is. its just annoying bc the first 4 months of owning the jeep it always engaged smoothly into third. Thank you for your advice on the trans swap. Im going to be doing some research into possibly doing a new ax15 over another nv3550

 

[ToeKnee217]

Give the MTL a few thousand before you pull the trans, mine didint do much the night I swapped it, but was loads better after about 1,000 miles

Does this problem get any better or worse with trans temp?

Yes I will continue driving it and see if it gets any better as it is my daily driver. Didn't seem to get any better towards the end of my drive today but ill keep that in mind once I go on a longer drive.

 

[robo512]

Yes I will continue driving it and see if it gets any better as it is my daily driver. Didn't seem to get any better towards the end of my drive today but ill keep that in mind once I go on a longer drive.

I hate to revive an old thread, but I am experiencing the same issue. Did the redline end up helping more after a few months of driving?

 

[ToeKnee217]

I hate to revive an old thread, but I am experiencing the same issue. Did the redline end up helping more after a few months of driving?

No prob this was due for an update.
I don't know if we had the same exact symptoms but
so far I've put 3k miles since the change to Redline and the third gear crunch has gotten MUCH better. I don't think it has done it again in a while tbh so just give it some time after you change your fluid and see if it resolves. Im able to downshift into third without problems anymore.

 

[Jwhutch]

I hate to revive an old thread, but I am experiencing the same issue. Did the redline end up helping more after a few months of driving?

I'm glad you revived the old thread. I have had similar problems with my NV3550. I have tried RP, Synchro-whatever, and the only thing that would make it behave is that outrageously expensive mopar stuff. So is Redline MTL a valid alternative to the Mopar stuff with the same results? Sounds like yes?

 

[Rubicon88]

I'm glad you revived the old thread. I have had similar problems with my NV3550. I have tried RP, Synchro-whatever, and the only thing that would make it behave is that outrageously expensive mopar stuff. So is Redline MTL a valid alternative to the Mopar stuff with the same results? Sounds like yes?

No.
There are no guarantees.
3 last and immediate examples at the shop.
One change got worse...one got better...one no change.

None of them had fresh fluid before the Redline switch and the one that got better had the most miles on it. Could that be attributed to just desperately needing new fluid? Possibly.

I know what you're looking for but there is no magical fluid out there.
There are some that work better than others for sure but don't buy into the Redline stuff too much or you might be sadly disappointed.

If yours is working well with the mopar fluid...stick with it.
It's a manual. Who cares if it's a little more expensive. Doesn't need changed that frequently.

 

[Rob L.]

3rd gear has always been picky in my TJ but @ 180k it was getting much more noticeable. I swapped to Redline MTL to see if it would help but I couldn't tell a difference. 5k miles later and 2nd gear started having trouble too. I went ahead and bought a reman'd at High Gear in Memphis for $1,250 (super satisfied when the tranny thus far)

I have 2k miles on the new tranny now and tried both Redline & some Synchromesh for kicks and giggles. While I will say that the Redline had a significantly quieter gear noise, I didn't notice a drastic improvement in performance. A smooth shifting 3550 has a lot to do with the driver in my opinion

I'll always use Redline unless I'm in a pinch for something quick but I wouldn't expect a drastic change in performance especially if it's time for a rebuild.

 

[Rubicon88]

A smooth shifting 3550 has a lot to do with the driver in my opinion

...... but I wouldn't expect a drastic change in performance especially if it's time for a rebuild.

Trimmed the fat here.

Absolutely positively perfectly said.

This is sarcastic but still...
I believe Jeep has a prerequisite for passing out manual tranny contracts. They must all be notchy and bonus if finicky and junk.

In all the years they used one excellent transmission. The T18

The rest...seriously...
The SR4 being the worst
T4 & T5 being close to the worst
The AX-5 not far behind

NSG370...well the board knows my opinion on that. Junk. It's a Chrysler Crossfire tranny. They still use that abomination to this day.

I will say the NV3550 is the best since the T18.
It's not as smooth as the AX-15 but it's tougher IMO. I have one in a plow truck for our lot...
The shit has been beat out of that. Still works great.

The AX-15 is OK too but considering they're all notchy (every damn Jeep tranny is) I elect for the 3550 durability.

 

[Mudflat]

Typical notchy jeep manual.

I would say it's coincidence more than anything. Will it grind in all rpm ranges?

However.....

Don't laugh.....

Did your seat move back one notch and not getting the pedal entirely pressed in? Floor mat preventing the clutch pedal from going all the way in?

I ask that because we fix this shit and you wouldn't believe some of the things that come in here and the why.

‘Good advice. Don’t overlook the simple stuff.
I know this isn’t a fix & won’t cure your problem, but you could try double clutching just that gear to see if it stops the grinding. It may also indicate if there’s a problem with the synchronizer on that gear.

 

[Rubicon88]

‘Good advice. Don’t overlook the simple stuff.
I know this isn’t a fix & won’t cure your problem, but you could try double clutching just that gear to see if it stops the grinding. It may also indicate if there’s a problem with the synchronizer on that gear.

That's it...
There will be an rpm spot (the sweet spot) that you don't even need to clutch it...

I'm not telling you to do that but I promise you there is a sweet spot with clutch in and a certain rpm and it will just fall right into 3rd gear.
You need to find that mark and start shifting in that spot for 3rd...

It could buy you a ton of time until you figure out what you want to do going forward

 

[Fishtaco]

Redline made my box a bit smoother but gained me a 1st to 2nd constant grind that wasnt there before, I now have to lose road speed changing from 1st and gently feel it in 2nd, I cant blame an oil that cost me $100 in Australia but can say it exacerbated a selector problem that was not noticed before! I still had factory oil in my 06 it had never been changed.
I wish you good luck if you decide on the MTL but if like me once the change was done and problem posted more members came forward saying they had to dump it than said its was worthwhile. Its a personal experience and I cant see a premium oil causing problems but it cant really fix problems in the long run either.

 

[Cheetokps]

I also switched to MTL and didn’t notice much improvement, it seemed to make the grinding in second worse even. I can upshift with no issues but downshifting into second I have to keep the clutch in for a few seconds and very gently go into second

 

[ToeKnee217]

I also switched to MTL and didn’t notice much improvement, it seemed to make the grinding in second worse even. I can upshift with no issues but downshifting into second I have to keep the clutch in for a few seconds and very gently go into second

This sounds exactly like what I had except with third gear. I was forced to shift just like you mention for about 1500 to 2k miles with the MTL until it resolved. I have not noticed any other difference as far as shift feel from whatever was in it originally to MTL. Still shifts like a jeep trans.
The Royal purple would grind into multiple gears and that's what prompted me to try MTL.

After resolving this issue. I don't really have any other complaints with the nv3550. IT actually shifts better IME as far as feel and positive engagement as compared to a 2013 Ive driven a couple of times with a 6 speed. (Very Sloppy).

 

[ToeKnee217]

Keep in mind guys that this jeep has relatively low miles and did NOT have a crunch before I changed the fluid. I changed the fluid to address a small trans leak.

 

[Cheetokps]

This sounds exactly like what I had except with third gear. I was forced to shift just like you mention for about 1500 to 2k miles with the MTL until it resolved. I have not noticed any other difference as far as shift feel from whatever was in it originally to MTL. Still shifts like a jeep trans.
The Royal purple would grind into multiple gears and that's what prompted me to try MTL.

After resolving this issue. I don't really have any other complaints with the nv3550. IT actually shifts better IME as far as feel and positive engagement as compared to a 2013 Ive driven a couple of times with a 6 speed. (Very Sloppy).

I've only put around 2k miles since I changed mine in December so hopefully more miles is all it needs