Weird noise / feel when pushing in the clutch while moving

[venom]

Hey Guys, I'm hoping someone can decipher what I'm about to describe and point me in the right direction as to what the cause is so I can fix it, assuming something is broken.

Here's the scenario, if I'm driving and I have my RPMs at the higher end of the spectrum for the gear (not over revving by any means) and I go to stop, when I push in the clutch I get a series of clunks and what feels like the Transmission / motor torquing. It happens like 3 or 4 times in as many seconds. In my mind, I see the motor torquing counter clockwise each time it does it. The closest thing that comes to mind that I've experienced that's anything like it is the overrun clutch on my tractor.

I looked at the motor mounts, and as far as I can tell they look good. Beyond looking for them to be physically broken, I'm not sure what else to check there. Not that I can logically see how that would be what I'm experiencing, I just don't know what to look for

So, can anyone give me some guesses as to what might be causing the problem, or help me troubleshoot? It's quite possible it's not a problem at all, and I'm just overreacting. I just don't remember it doing this before, but it's been a while since I've actually had it out and up to speed.

Thanks!

 

[Lumpy Grits]

What RPM is this?
The PS engine mount is a known issue.
Also, check the tranny mount and torque arm.
Make sure your skidplate is tight.
Check the bellcrank for slop/play and the linkage on the clutch.
Check your body mounts especially the one under the grill.
Put a wrench to every bolt/nut you can get to. Do this ASAP!
LG

 

[venom]

What RPM is this?
The PS engine mount is a known issue.
Also, check the tranny mount and torque arm.
Make sure your skidplate is tight.
Check the bellcrank for slop/play and the linkage on the clutch.
Check your body mounts especially the one under the grill.
Put a wrench to every bolt/nut you can get to. Do this ASAP!
LG

Thanks LG!

I don't have a tach installed, so I can't say with any certainty, but I'd guess somewhere around 2500 RPM back to idle.

What should I look for in the PS engine mount? A visual inspections reveals nothing. I could put a prybar on it and see if it moves excessively, but beyond that I'm not sure I would know what to look for.

I'll run through all the bolts and other checks you mentioned to see what, if anything, I can find. I am actually planning on replacing the body mounts in short order. I'm doing a refresh of sorts and they are on my ever growing list. They are not in the best shape. I've neglected this for far too long.

 

[Torxhead]

Other checks for bad motor mounts would be to look and see if the rear of the valve cover is too close to the firewall as when the mounts go bad the engine will sag to the rear. The clutch bell crank should be perpendicular to the frame also, this will also indicate if the engine is sagging.

 

[venom]

Other checks for bad motor mounts would be to look and see if the rear of the valve cover is too close to the firewall as when the mounts go bad the engine will sag to the rear. The clutch bell crank should be perpendicular to the frame also, this will also indicate if the engine is sagging.

Thanks Torxhead, I'll check that this evening and see what it looks like. I never realized it would sag and cause issues. You learn something new every day. It wouldn't surprise me, as I've mentioned I've been pretty neglectful.

 

[venom]

I think that the motor mount is good. I tried to grab some pictures of the motor angle and the bellcrank, but I don't think they show what they need to show. Those picture are after the torque arm. There isn't any play, so to speak, in the bell crank. What I do think is an issue is the torque arm. It looks like the bushings need to be replaced to me. What do you think? Please don't judge the condition of things too harshly.

Valve cover to firewall:

Actual engine angle:

Bellcrank:

 

[Lumpy Grits]

That valve cover is too close to the firewall.
I would suggest you replace both engine mounts, and the tranny mount with the newer ploy type.
FWIW: 2500 rpm is pretty much the shift point for our 6's.
LG

 

[Torxhead]

That valve cover is too close to the firewall.
I would suggest you replace both engine mounts, and the tranny mount with the newer ploy type.
FWIW: 2500 rpm is pretty much the shift point for our 6's.
LG

Yup!, take the advice of a wise old man. Thanks for sending in those pics.

 

[venom]

That valve cover is too close to the firewall.
I would suggest you replace both engine mounts, and the tranny mount with the newer ploy type.
FWIW: 2500 rpm is pretty much the shift point for our 6's.
LG

Yup!, take the advice of a wise old man. Thanks for sending in those pics.

Yikes! I'll definitely be taking the advice. You know, I've had this jeep for just under 30 years, and it's sat more often than not for the past 10, and in that entire time I seem to remember the engine sitting like that. That said, I was definitely young and dumb and could just be trying to justify Oh well, it'll get fixed right now.

Thanks again!!!

 

[Lumpy Grits]

IF, I was that 'wise', I would have spelled Polyethylene 'rite'.

LG(who ain't as old as T'Rex(Torxhead)

 

[venom]

I'm parts shopping, and I have to ask, are the polyurethane motor mounts from the likes of prothane worth the extra cost? I'm going to go under the assumption that they are indeed worth the money and that's what I should be purchasing, but if someone has some real world insight, I'd love to hear it. I mean, it's only $20 more per side, but I'd hate to spend that on snake oil.

 

[Lumpy Grits]

Been run'n these for over 20 yrs now.
Buy once-cry once..........
https://www.mountainoffroad.com/jeep-cj/cj-motor-mounts/bomb-proof-motor-mounts.html
LG

 

[venom]

Been run'n these for over 20 yrs now.
Buy once-cry once..........
https://www.mountainoffroad.com/jeep-cj/cj-motor-mounts/bomb-proof-motor-mounts.html
LG

Those sure look different, but if they've lasted 20 years now, they must be doing something right. At this point in my life, I'm definitely into spending more for proven quality and durability. On the list they go.

I assume the Transmission mount from them is the way to go, too? It doesn't look like their torque arm stuff is any different than what I've seen elsewhere, and the price is the same so I'll probably get it all at the same place.

 

[Lumpy Grits]

I bought all the mounts from them.
The torque arm 'donuts' are poly and not the soft rubber that was OEM.
Even at today's prices-I would buy then again.
LG

 

[venom]

I bought all the mounts from them.
The torque arm 'donuts' are poly and not the soft rubber that was OEM.
Even at today's prices-I would buy then again.
LG

That's what I'll be doing. Just need to get the CFO (aka the wife) to sign off on the purchase. Going from $100 for everything to $300 is a bit of a jump

 

[venom]

Stupid question...what order should I replace these in? The motor mounts first, then the Transmission mount and torque arm? That's the way I see it, logically, but my logic isn't necessarily sound

 

[venom]

Parts are on order. My wife gave me the, "this better be the last time you have to replace these" look. How that woman tolerates me, I'll never know.

 

[Hedgehog]

I'm surprised, nobody has mentioned clutch or throw out bearing. These wonders of the mechanical world of jeeps are generally 100% correct though. Maybe an odd feeling in the clutch along with noise when the CJ is running is all about the motor and Transmission mounts. No matter what replacing yours would not be wasted money, your engine most certainly is to far back.

 

[Torxhead]

Stupid question...what order should I replace these in? The motor mounts first, then the Transmission mount and torque arm? That's the way I see it, logically, but my logic isn't necessarily sound

I would suggest replacing the two front motor mounts first. You will have to move the motor forward to position the mounts up. I was able to push it forward with 2 bottle jacks at an angle pushing the engine up and forward. An engine hoist will work also. If you get the ones from m.o.r.e. it is very noticeable of just how solid those suckers are. I have tried replacing with both the rubber and poly mounts and think the solid mounts are the way to go.

 

[Lumpy Grits]

with HH and T'head.
Loosen the tranny mount to help with this movement.
Don't forget the bushings in the clutch bellcrank. BTDT
LG