SM420 issues

[TroyaCantrell]

So got the CJ out of the garage and took the wife for her first ride around the block.
Good news and ad news

Good news:
Handles much better, had serious steering issues, and the new tires helped as well, seats are very comfortable!

Bad news:
Transmission however made a ton of noise. One, it ticks with clutch depressed. Two, occasionally makes a
loud rattle (best I can describe it) sound like a shield vibrating, don't feel a vibration just the noise.

Three, Checked oil in it again and it looks like a mocha. Light brown, I would say foamy but don't see bubbles.

Four, clutch peddle kind of stiff and does not come all the way back up. I don't feel any slipping though. Fair punt no play at he top, a little slack in the linkage cable.



1 sounds like throw out bearing.
2 no ideas yet and need help
3 what the hell, water in it ?
4 the SM420 was a swap by PO and I not sure how much knowledge he had on the topic.

 

[Incommando]

3 certainly sounds like water contamination. That could possibly be the cause of #2. If this has sat a lot you may have a rust issues in the clutch. If so they may work themselves out with use

 

[mtnwhlr]

Did you use a new clutch cable? If not it could be sticking and causing the stiff pedal and it not coming all the way back up. And that will cause the throwout bearing to ride on the pressure plate. And that could be your noise.

 

[csuengr]

Definitely have water in the oil. The rattling sounds like a bad pilot bearing.

 

[TroyaCantrell]

Definitely have water in the oil. The rattling sounds like a bad pilot bearing.

Thanks, seems like it was while coming off the clutch, when power is applied. Then goes away.

 

[TroyaCantrell]

Did you use a new clutch cable? If not it could be sticking and causing the stiff pedal and it not coming all the way back up. And that will cause the throwout bearing to ride on the pressure plate. And that could be your noise.

I didn't change it and it doesn't look new. Doesn't look 46 years old either so hard to tell. The ticking is when the clutch I depressed, no ticking with the clutch peddle released while in gear or in neutral.

I will change oil for starters. Then get the wife to work the peddles while I watch what is happening underneath with the linkage.

 

[mtnwhlr]

I don't think it would be your Transmission then because it isn't turning when you have the clutch depressed. It sounds like the throwout bearing or the way it is riding on the pressure plate.

 

[TroyaCantrell]

ok, thanks once again for all the assistance. I pulled the plug and drained out the mocha colored goo, absolutely had water inside.

From all the advice and research I have been doing it sounds like there are two additional issues, the throw out bearing and pilot bearing. Given everything i read about adapting the SM420 to the v6 getting the pilot bearing and bell housing aligned and the tolerances set correctly is critical to the well-being of the system. That being said I think I will have a professional look at the bearing issues and insure proper configuration of that as well as the clutch fork setup. I have changed a clutch before but i am not confident on getting the pilot bearing and bell housing configured correctly, also never been inside a Transmission . I will do some tightening of the clutch linkage because it does have some play in it. Not a ton, but some, so we can see if that makes any difference in the throw out bearing noise.

So, What should I do to clean out the inside of the Transmission and insure i get all the out of it?

There is a panel on the side that comes off, can that be removed without parts flying out? Any suggestion on solvent or chemical and process to use to clean it out and so i can do an inspection?

As always you counsel is greatly appreciated.

 

[tarry99]

ok, thanks once again for all the assistance. I pulled the plug and drained out the mocha colored goo, absolutely had water inside.

From all the advice and research I have been doing it sounds like there are two additional issues, the throw out bearing and pilot bearing. Given everything i read about adapting the SM420 to the v6 getting the pilot bearing and bell housing aligned and the tolerances set correctly is critical to the well-being of the system. That being said I think I will have a professional look at the bearing issues and insure proper configuration of that as well as the clutch fork setup. I have changed a clutch before but i am not confident on getting the pilot bearing and bell housing configured correctly, also never been inside a Transmission . I will do some tightening of the clutch linkage because it does have some play in it. Not a ton, but some, so we can see if that makes any difference in the throw out bearing noise.

So, What should I do to clean out the inside of the Transmission and insure i get all the out of it?

There is a panel on the side that comes off, can that be removed without parts flying out? Any suggestion on solvent or chemical and process to use to clean it out and so i can do an inspection?

As always you counsel is greatly appreciated.

Troy,

That's a PTO port and yes you can take it off..............nothing will come out except oil.......The best thing although would be to take the top cover off with the shifter.............put it in neutral and it will come off with a little wiggle.... ....when it goes back on it you just have to make sure each fork is back in the same slots it came out of............as long as you don't move anything its a piece of cake...........once off I would just flush it from the top down with 3-4 quarts of a thin cheap motor oil getting it around your case and gear set.......then let it drain overnight..... if you have a nice heat lamp put it on it overnight and all the oil and water will be in the pan in the morning.

The old clutch cables are hard to find if you need a new one I have a spare.

 

[alpha6]

"I pulled the plug and drained out the mocha colored goo, absolutely had water inside."

Bummer amigo. But at least you are finding the problems before serious damage takes place. That's the thing about buying these jeeps before you get them fixed up is constantly wondering, "what the heck was the PO thinking?"

Keep at it...you are doing a great job and the pics look great...especially the one of the kitten laying in the jeep.

 

[BC CJ]

The SM420 is a beast of a Transmission ; feels like driving a 5-ton truck. I had one swapped into my old land cruiser. Once you have these other issues sorted out don't be alarmed by a fair bit of noise from that Transmission (gear whine). It's a slow shifting, uncomfy tranny over-all but the 7:1 first gear is awesome on the trail! Also, if it is grinding like crazy trying to get into lower gears after stopping shift into 3'd first, then grab the lower gear. It slows the gears down or something... I dunno, just worked for me to avoid the big grind

 

[JR74CJ5]

Take your clutch cable out of the jeep, and hang it on a fence etc. Poor a lot of lubricant down the inner cable sleeve. Let run in there good, have a drink... then come back, poor more in, you can work it back and forth a bit now if you want, or if you are like me, have another drink then repeat step two again.

Once it is moving nice and smooth (it should after a few of these "steps") then get her back in the jeep. Make sure all your springs are good and tight.

Don't adjust ALL of the freeplay out of the pedal. With linkage you need an 1" of free play. With cable i think it is slightly less, but stay closer to an inch than none.

After all that, if still seems like its doing what you are describing, I'd say clutch and throwout bearing. Problem is WHILE you're in there (bell housing) it would be a good idea to do pilot bushing too...

As another said already, sometimes the "sitting" a while will do funny things to clutches too... It "may" wear back to normal... but it also may blow the clutch disc leaving you on the side of the road...


~ JR

 

[TroyaCantrell]

Thanks JR but that doesn't sound like mine. The clutch peddle rotates the assembly with the break. The assembly pushes a solid rod towards the rear. The rod connects to a lever the other side is where the cable connects. The other end of the cable pulls the clutch fork.

The cable is just exposed though, not inside a tube and adjusts from either end.

Tried to get a pic but hard to get one up there. At least while all my tires are still on the ground )

Neither the Chilton or universal manual has the right picture though.

I tried more and less play and it did not change the sound. I climbed under and listened while the wife worked clutch and it is ticking, you can feel it in the cover and bell housing.

 

[TroyaCantrell]

Thanks BC, I hope to have enough drive time soon to feel it myself. Only really driven about 5 total miles in it so far. No grinding that I remember, when hitting the right gear anyway.

I have heard it is sturdy.

 

[TroyaCantrell]

I pulled the top off and got it cleaned up inside. Everything looked good, at least to my untrained eye. You could see just a little rust starting on some on gears but no damage and no pitting. Turned the top over and found a bit there too so cleaned that up.

I ran 3qts of regular oil through and let it drain.

Had some trouble getting it back together though. Either the shift fork got moved or the gear got moved. One way or the other I got it back in and shifting.

 

[tarry99]

I pulled the top off and got it cleaned up inside. Everything looked good, at least to my untrained eye. You could see just a little rust starting on some on gears but no damage and no pitting. Turned the top over and found a bit there too so cleaned that up.

I ran 3qts of regular oil through and let it drain.

Had some trouble getting it back together though. Either the shift fork got moved or the gear got moved. One way or the other I got it back in and shifting.

Troy,

Glad to hear you got it flushed out............on the throwout bearing make sure you do have some clearance. And I will not say how much .......because in this type of mod picking or machining the right length candlestick / bearing housing and the correct throwout bearing is critical.

I would as the motor is running and wheels blocked & Transmission in neutral lightly put some hand pressure on your clutch pedal you should first feel the free play and then once the throwout bearing contacts the fingers on the pressure plate an audible tone change should be heard. If it becomes noisy at that point its the throwout bearing............A noisy throwout bearing can be run for a while but obviously will not get any better.
Pilot bushings do not create noise unless they are totally worn out which in that case eats up your input shaft Bearing in the front of the Transmission .

You mentioned a tinning noise. On the Dauntless Buick 225 V6 there is normally a sheet metal dust cover attached between the Bell Housing and the rear of the engine block........I believe 5 bolts hold it on , if any are missing the rattle will drive you nuts.

 

[JR74CJ5]

Thanks JR but that doesn't sound like mine. The clutch peddle rotates the assembly with the break. The assembly pushes a solid rod towards the rear. The rod connects to a lever the other side is where the cable connects. The other end of the cable pulls the clutch fork.

The cable is just exposed though, not inside a tube and adjusts from either end.

Tried to get a pic but hard to get one up there. At least while all my tires are still on the ground )

Neither the Chilton or universal manual has the right picture though.

I tried more and less play and it did not change the sound. I climbed under and listened while the wife worked clutch and it is ticking, you can feel it in the cover and bell housing.

Ah gotcha... I thought we were talking about a clutch cable conversion from the linkage.

Sorry about that...


~ Jr

 

[TroyaCantrell]

Ah gotcha... I thought we were talking about a clutch cable conversion from the linkage.

Sorry about that...


~ Jr

I must say I like your process though! Although the quality of my work degrades if it takes too long. )

 

[TroyaCantrell]

Update/resolution:
So as I mentioned I took the CJ in for the noise in the tranny issue and here is what we found. Clutch is fine, bearings are fine! As it turns out there were a couple issues that were causing the issue.

1. Broken rear Transmission mount
2. Custom (crappy) rear spacers on Transmission crossmember
3. Loose / bad/ missing bolts on bell housing to engine.

So the PO when installing or having installed the SM420 made some custom spacers to go between the Transmission and the crossmember. They were too tall. Over time the working of the clutch probably caused the bolts to loosen in the bell housing.

What was happening was when you pushed in the clutch is was causing the whole thing to shift due to the loose bolts and flywheel was hitting the dust cover that Tarry mentioned. You could only see it when operating the clutch while it was running and even then barely. The too tall spacers were also putting too much up pressure on the back of the Transmission increasing the movement.

Drove it home on the longest ride I have had in it. About 10 miles, and it ran great, no noise, well plenty of noise but only noise I expected from he Transmission . Got two thumbs up from old iron fans on the way too. Seats worked out well, steering worked well. Still a bit of play but not in the wheel and only got it up to about 45 but tracked very well.

I had also replaced the speedo cable before we left and that worked, was pretty accurate but it stopped working on the way home, stuck at 30mph so I will have to look at that now.

A little mad I didn't figure this out on my own but that is life. Live and learn.

I also screwed up when installing/ rebuilding the steering box. There was no mark on the new sector shaft so I had to make some estimates when re-installing the pitman arm on the end and was apparently off. It is installed a tooth or two too far towards the rear because turning to the left causes the drag link to touch the Transmission dust cover. Not as bad now that the whole thing doesn't move around. I need to see how close it comes to the hard stop on each side and adjust it I guess.

Something else to look at.

Thanks everyone for the advise.