6-speed transmission making clunking noise

Ray662

Ray662

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Mississippi
So I have a 6 speed with what I’d like to describe as a clunk. So as you can hear in the video it’s present most of the time. I will say that when I go to shift and press the clutch in and pop it and and in slowly it’s fine. It’s when it’s under a load it wants to clunk. Almost like maybe the trans is moving? Or motor mounts? Hell idk maybe yal know what’s goin on? Thanks!!
 
Have you had the skid plate off recently?

I know it sounds weird, but on mine if I lift the tranny to do so and then set it back down on the skidplate and tighten up the 4 nuts in that 'flexed' position, something feels off with the shifting. So I loosen the 4 nuts, go for a short 2 minute drive, making sure to hit a couple bumps along the way so it settles in, then come back and tighten up. Makes no sense as there is no external shifter linkage, but have noticed the phenomenon enough times to prove it to myself as I take my skid plate off 2 or 3 times a year.

Main reason this is top of mind is that I had the skid plate off a couple days ago to fluid film for the winter and forgot, so am doing this exact thing this morning.
 
Interesting.. it has done it since I first got it a couple months ago. It has a 3 in lift and spacers on the skid plate. I haven’t had it off tho.
 
have you had the console off and checked the thick rubber boot that seals the shifter hole through the tub? That thing blocks a lot of normal mechanical noise and they tend to get torn up. Unfortunately they're not cheap for a 6 speed, either. Mine is torn and I bought something from another model that I was thinking I'd retrofit but haven't got around to it.

Other than that, I didn't hear much I would say is abnormal. The NSG370 just seems to be a noisy transmission.
 
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Ray662 said:
Interesting.. it has done it since I first got it a couple months ago. It has a 3 in lift and spacers on the skid plate. I haven’t had it off tho.
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Does it only happen when shifting into 2nd/4th/6th?

I’ve read some others who have a large lift and skid plate spacers have issues with the shift lever actually hitting the tub when they shift. Large enough changes can actually prevent some people from getting it into gear at all
 
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You know... I’ll test that.. we are at a Christmas parade and I’ll check when I drive home. I will say it does clunk coming out of first into 2nd
 
Doesn’t seem to be any specific gear.

It does it from 1-2 and 2-3 sometimes 4 but like I said if I come off the gas let everything settle the shift it’s smooth. It’s so weird
 
I have an 06 with a six speed and if your are talking about the click (what I call it ) that happens when changing from one gear to another , I think its normal .
 
That sound is a universal machodometer rolling over. It measures your maniless. Driving jeep manuals increase your maniless after each shift.
 
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Ray662 said:
So I have a 6 speed with what I’d like to describe as a clunk. So as you can hear in the video it’s present most of the time. I will say that when I go to shift and press the clutch in and pop it and and in slowly it’s fine. It’s when it’s under a load it wants to clunk. Almost like maybe the trans is moving? Or motor mounts? Hell idk maybe yal know what’s goin on? Thanks!!
Click to expand...
Have you changed the Transmission Fluid since you got the Jeep? The Royal Purple Synchromax is really nice in the 6-speed.
 
Ray662 said:
I put penzoil synchromesh in it when I did fluids
Click to expand...
Ok, just mainly making sure you had changed the fluid. I can’t listen to the sound bc I’m in bed and wife is asleep, but I will try to come back in a few hours to listen.
 
JMT said:
Have you changed the Transmission Fluid since you got the Jeep? The Royal Purple Synchromax is really nice in the 6-speed.
Click to expand...
I used the Royal Purple for a while. It was a noticeable improvement over the Pennzoil Synchromesh I was using before. I ended up swapping it with Royal Purple MTL, which actually significantly improved things over the RP. (Note that you want MTL and not MT-90.)

The Pennzoil Synchromesh was terrible compared to the OEM fluid. Probably not a bad fluid per se but this transmission is picky. It was bad enough I was thinking about a reman.
 
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Ray662 said:
So I have a 6 speed with what I’d like to describe as a clunk. So as you can hear in the video it’s present most of the time. I will say that when I go to shift and press the clutch in and pop it and and in slowly it’s fine. It’s when it’s under a load it wants to clunk. Almost like maybe the trans is moving? Or motor mounts? Hell idk maybe yal know what’s goin on? Thanks!!
Click to expand...

You ever figure this out?
 
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