Gearbox grinding

Brecontj

Brecontj

Member
Joined
Feb 28, 2020
Messages
62
Location
Wales
Hi all

I,m getting an intermittent grinding slipping the Jeep into 1st and second, second down to first. Worse on a cold start, but it can come in when the Jeep is warm, once or twice on a run, then nothing for a few days. First into second feels tight, then it umps in and makes a grinding noise.

Its a relatively new clutch, bearing and fork. (10k miles) Fluid is good. It doesn't make any difference if I pump or double de clutch so I don't think its air.
The jeep is on 100K miles.



Could it be worn selector? I,m unfamiliar with the selector - the linkage under the gaiter etc.

Could it be a worn down rod in the slave cylinder?

I,m based in the Uk so hope the terminology translates ok

Thanks
 
You've got the NV3550. It's not a smooth transmission. The grind on the 1-2 shift is notorious. The good news is that it's otherwise a very stout transmission as long as you don't shift like a Le Mans driver. Putting a high-quality synthetic fluid inside is probably your best bet. I use what everyone recommends on this forum: Redline MTL. The 1-2 grind is still there on cold days, but it goes away after a few miles.
 
  • Like
Reactions: Jerry Bransford
I’ve got an ‘06 and recently switched to Amsoil Sycrhomesh Transmission Fluid after running redline for a few years.
I’ve got a NSG370 6 speed trans but I have similar issues in first and second gear.
Redline worked okay during summer and when temperatures are up but come winter and it was nearly undrivable.
Since it was time to change the fluid out anyway I decided to try pennsoil synchromesh and was instantly able to shift gears easier. I prefer to use synthetics though so I decided to go with Amsoil shortly later.
Just something to keep in mind.

https://www.amsoil.com/p/manual-synchromesh-transmission-fluid-5w-30-mtf/?code=MTFQT-EA
 
bromel said:
You've got the NV3550. It's not a smooth transmission. The grind on the 1-2 shift is notorious. The good news is that it's otherwise a very stout transmission as long as you don't shift like a Le Mans driver. Putting a high-quality synthetic fluid inside is probably your best bet. I use what everyone recommends on this forum: Redline MTL. The 1-2 grind is still there on cold days, but it goes away after a few miles.
Click to expand...
 
Thanks Guys, I’ll look up an equivenent transmission fluid in the uk
Where do I locate the selector boots?
 
Don Ashcraft said:
I’ve got an ‘06 and recently switched to Amsoil Sycrhomesh Transmission Fluid after running redline for a few years.
I’ve got a NSG370 6 speed trans but I have similar issues in first and second gear.
Redline worked okay during summer and when temperatures are up but come winter and it was nearly undrivable.
Since it was time to change the fluid out anyway I decided to try pennsoil synchromesh and was instantly able to shift gears easier. I prefer to use synthetics though so I decided to go with Amsoil shortly later.
Just something to keep in mind.

https://www.amsoil.com/p/manual-synchromesh-transmission-fluid-5w-30-mtf/?code=MTFQT-EA
Click to expand...
I’ve got a 5w 30 fully synthetic in now
Do you guys have a thing called moly slip over there? It’s a gearbox sticky substance.
I’m reluctant to go down that route though.
What is the pensoll? How’s it different to the 5w 30, is it just a better quality 5w30?
Thanks
 
Brecontj said:
I’ve got a 5w 30 fully synthetic in now
Do you guys have a thing called moly slip over there? It’s a gearbox sticky substance.
I’m reluctant to go down that route though.
What is the pensoll? How’s it different to the 5w 30, is it just a better quality 5w30?
Thanks
Click to expand...
Hi again, I’m checking with amsoil to see if they have a Uk agent
Thanks
 
  • Like
Reactions: Don Ashcraft
bromel said:
You've got the NV3550. It's not a smooth transmission. The grind on the 1-2 shift is notorious. The good news is that it's otherwise a very stout transmission as long as you don't shift like a Le Mans driver. Putting a high-quality synthetic fluid inside is probably your best bet. I use what everyone recommends on this forum: Redline MTL. The 1-2 grind is still there on cold days, but it goes away after a few miles.
Click to expand...
Thanks Jerry, so I know now the gearbox isn’t on the way out.
The oil is clean when I change it, no filings or metal slithers, always a good sign
 
Ok, understood Jerry.

I found a video on YouTube about the rubber boots, I know what this means now.
Thanks again
 
Brecontj said:
I’ve got a 5w 30 fully synthetic in now
Do you guys have a thing called moly slip over there? It’s a gearbox sticky substance.
I’m reluctant to go down that route though.
What is the pensoll? How’s it different to the 5w 30, is it just a better quality 5w30?
Thanks
Click to expand...
I’ve read something about Molly recently but I’ve never used it. The Pennsoil is just a brand that makes synchromesh trans fluid. I’m not a fan of Pennsoil because the additives(paraffins) they use. It seemed to be slightly thinner than 5w30 to me. What I looked for was a fluid that specifically states “synchromesh” and that it meets “Chrysler MS9224”.
 
Top Bottom
Back