SBC Con OFE = undriveable

[Cattletrkr]

I've had my new clutch (OFE) in for a couple weeks now. That thing it ungodly jumpy. Empty it's fine, but even with just an empty trailer it's a chore to backup and not so fun starting out in first. With a full load (35-40K) it's almost impossible to backup. I find myself getting it started and then just popping the clutch. I thought I figured out a way to drive around it, but that still doesn't work. Once I'm moving and shifting everythin is fine and dandy. It's just first and reverse that are awful.

Will it get better with a few more miles (about 1400 so far) or do I need to start looking for a "fix". I can't keep going the way it is, I'll break something for sure.

The clutch and bearings were all that got replaced. No upgraded hydraulics or replacements were done.

 

[Joseph Donnelly]

It is important to resurface the flywheel with a Blanchard type grinder. Also, your clutch should be smoother than my con-Fe that I find quite acceptable. However, I don't try to tow double the Dodge rated maximum weight like you do! You may have to go to the lower torque capacity con-o for more smoothness but if you slip it like you must be trying to do to get moving, it will glaze. You can try a bit more rpm on take-off to allow the feramic disk to slip some, but you really need the gearing of a medium duty truck behind that Cummins.

 

[Cattletrkr]

My stock clutch was fine for the better part of 170K. It did get jumpy in reverse but that came and went. I knew something was up when it didn't go away. I never slipped the stocker other than with the pedal.

Flywheel was machined at a truck shop. Don't know what type of grinder they have, but it shouldn't be a cheapy.

Also, reverse is still impossible to get into w/o hitting another gear first. Is that a cluth thing or a synchro thing? First is a little stiff, but it works. Reverse will not go and I don't try 'cause it doesn't so much grind as buzzes the gears.

 

[Gary - K7GLD]

Also, reverse is still impossible to get into w/o hitting another gear first. Is that a cluth thing or a synchro thing? First is a little stiff, but it works. Reverse will not go and I don't try 'cause it doesn't so much grind as buzzes the gears.

If the transmission shifted properly BEFORE the clutch switch, it should still do so afterwards - if it doesn't, you undoubtedly have some sort of clutch engagement/disengagement issue that is causing the problem - most likely NO fault of the clutch disc itself - and when you get THAT issue resolved, the excessive chatter will possibly go away as well...



You might want to look carefully at the position and travel in the clutch slave cylinder - possibly not optimum with the new clutch, and the flywheel resurfacing.

 

[GCroyle]

Possible cause.

Cattletrckr,



Any clutch can create chatter if anything in the environment, release system, installation faults, damaged in handling or any other of a myriad of sources makes the clutch chatter.



Let's assume that the parts are capable of working correctly and the release system is not telegraphing a signal to create chatter, lots of additional assumptions, but bottom line = chatter.



Q. Did the replaced system work OK for a couple of days or weeks before it started chattering?



Q. How does it drive without the load?



Q. Can you just for our collective information re-state your load? What do you weigh, truck + trailer + payload, total gross weight?



I'll check back for your answer to the first question in particular, then add to my . 02$.



I do have an idea.

 

[JasonCzerak]

with the ConFE (new pressure plate) I did have a tough time getting it into gear and shifting with any decent speed. However the upgraded electronics and adjusting the peddle out a bit allowed to release the pressure plate a bit more, making things almost like stock.



backing up, more RPM helps,



1st, I have ZERO grabbyness, just goes smooth.

2nd, she grabs and shakes like reverse if I go slow, if I got fast, you feel one "slip" and then it grabs and your off.



Try doing some 3rd gear launches and "slipping the poop" outa the clutch, 3000rpm and just drag it out to get the (empty) truck moving, that will help seat the clutch in better. Do this after few hundred miles of stop and go traffic. tho.



Make sure you cruise around for a good 10 minutes before shutting things down to cool the clutch and what not down!

 

[Cattletrkr]

If the transmission shifted properly BEFORE the clutch switch...
You might want to look carefully at the position and travel in the clutch slave cylinder - possibly not optimum with the new clutch, and the flywheel resurfacing.

The difficulty going into gear was there before. I'm not saying that I think the OFE has anything to do with that. I'm treating that as a separate issue... . just in the same thread is all.

Q. Did the replaced system work OK for a couple of days or weeks before it started chattering?

Ya worded that one a little funny. Was the new clutch fine at first? No. Was the old one fine when I took it out? No. I have the same jumpy bouncy reverse as before the change.

Q. How does it drive without the load?

More or less just fine. I can tell it's a little grabby in reverse and sometimes in second, but not bad by any means. Loaded is when there's a problem.

Q. Can you just for our collective information re-state your load? What do you weigh, truck + trailer + payload, total gross weight?

Truck and traliler empty weigh a little over 15K. Normal GCVW is gonna be somewheres around 35-38K but I will routinely go over 40K.

backing up, more RPM helps,

Not when I need to go slow. One foot on the clutch, one on the brake, and one on the go-pedal...

The guy who did the replacement should know what he's doing. He been a big rig mechanic for I'm guessing 20 years. But I know he doesn't work on too many pickups. I think I might have to take it in to my dealer who I should have had do the work in the first place and see if they can straighten things out a little bit. I talked to the service manager a little bit the other day about something else and he asked about the clutch. He asked if any work was done to the slave cylinder such as replacing it or whatever. He sounded a little surprised when I said no.

Thanks for taking an interest

jake

 

[Gary - K7GLD]

The difficulty going into gear was there before. I'm not saying that I think the OFE has anything to do with that. I'm treating that as a separate issue... . just in the same thread is all.





Ya worded that one a little funny. Was the new clutch fine at first? No. Was the old one fine when I took it out? No. I have the same jumpy bouncy reverse as before the change.





More or less just fine. I can tell it's a little grabby in reverse and sometimes in second, but not bad by any means. Loaded is when there's a problem.



Truck and traliler empty weigh a little over 15K. Normal GCVW is gonna be somewheres around 35-38K but I will routinely go over 40K.



Not when I need to go slow. One foot on the clutch, one on the brake, and one on the go-pedal...



The guy who did the replacement should know what he's doing. He been a big rig mechanic for I'm guessing 20 years. But I know he doesn't work on too many pickups. I think I might have to take it in to my dealer who I should have had do the work in the first place and see if they can straighten things out a little bit. I talked to the service manager a little bit the other day about something else and he asked about the clutch. He asked if any work was done to the slave cylinder such as replacing it or whatever. He sounded a little surprised when I said no.



Thanks for taking an interest



jake

Reading all the above, I suspect your basic problem is not the clutch - but rather, driveline looseness and wear - U-joints, differential gear lash, and especially the center support. Under load, looseness in the driveline makes it all act like a big rubber band, loading up with low vehicle movement, them when the slack is taken up, BAM! - and it lurches forwards or backwards depending on gear - then instantly begins the same thing all over again as the slack returns - all very rapidly, of course.



Lots of guys here have done clutch upgrades just as you have - and while some of the chatter was there before the swap, a new higher performance clutch disc often surfaces and aggravates a driveline condition that was already there - but now it seem worse because of the more positive, non-forgiving clutch.



Good luck.

 

[Cattletrkr]

I thought I figured out a way to drive around it, but that still doesn't work.

What I tried was once the truck started moving the slightest bit, I pushed the clutch back in a little. I was able to back up ever so slowly this way with minimal jumping. That trick doesn't seem to work anymore.

 

[ROADWARRIOR]

Does your truck have a two piece drive shaft? If so, how is the carrier bearing?



Dan

 

[icman95]

I think I have at least a partial solution to your problem. I just had the same clutch put in my truck for towing my 5th camper. At first the going into 1st and rev problems were just the same as yours. The guy who installed it is very familiar with these clutches and pinpointed the problem right away. The upgraded clutch needs more travel from the slave cylinder that the stock slave can give. South Bend makes a replacement slave that is adjustable and will make your engagement problems a thing of the past. Just had mine put in last week and WHAT A DIFFERENCE! Call up South Bend and they'll help you out-talk to Pete.



As far as backing up-well you are moving a buttload of weight with the thing. I drive a commercial vehicle for a living which grosses at 33k and you're pushing your little (don't mean disrespect by saying little-just as compared to a commercial vehicle) pickup WAY, WAY overboard. Try backing up in 4wd low. The lower gearing will make things a bit easier, but I'm not sure how much it will help with double the rated load. You can't really blame the equipment for the owner's abuse of it. Good luck.

 

[GCroyle]

Suggestion:

Thanks for the followup. These are the suggestions based on your latest update.



Ya worded that one a little funny. Was the new clutch fine at first? No. Was the old one fine when I took it out? No. I have the same jumpy bouncy reverse as before the change.



The question was to determine if it was OK for a short time, then started chattering, you above statement indicates that the problem is a carryover, correct?



I helped a CTD owner in Jackson TN who went through several systems trying to find the source of the chatter, he went through the driveline with a fine tooth comb and this is a short summary of his ordeal.



He somehow took a cable comealong and put a choker on the front of the drive axle and put a pull on it to the receiver hitch. This took the existing slack out of the loose bushings, chatter abated.



His next move was to replace the leaf springs due to loose/worn spring bushings.



I'm heading in the same direction as Gary-K7GLD, driveline wear, somewhere.



All engine mounts, transmission mounts, all u-Joints (I have replaced a joint that looked fine until you opened it up), center bearing, driveline angles, and to a lesser extent the pedal cluster. We have seen a lot of Ford's with completely worn out pedal clusters, stick your head under the dash, work the clutch pedal, look for sloppy motion transfer, like bad tie rod inspection.



If none of the above would have been the story, my first guess from yesterday (until you pointed out the carryover of the problem) would have been hot spots in the F/W that cannot be ground out during normal resurfacing. We have researched this using a NuLine TH134 hand held hardness tester and a really sharp drill bit. The baseline of the casting is about 250-260HB and in the hot spots it is 500-600HB. This is where the drill comes in, try drilling into the non friction area, no problem, now try in the hot spots with the same pressure, it ain't gonna drill. The Cummins Dodge F/W can be a perfectly good looking reground F/W and be carrying the cleaned up hot spots and these hot spots become HIGH spots because they take up more volume due to the transformation into a hot spot shortly after reuse, resulting in chatter. We have measured these before and after resurfacing, they do not go away, they just look better. I do Clutch 101 seminars in the field and the techs ears perk up cause this is the same problem in brake with hot spots. We also consulted with a senior engineer at our sister company Webb Wheel, we are both members of Marmon Corp. he gave us an earful and eyeful about these invisible hot spots.



Good luck, please keep us updated.



Gary-K7GLD I will be in Portland, Eugene and Spokane 8/6-16.

 

[Gary - K7GLD]

If none of the above would have been the story, my first guess from yesterday (until you pointed out the carryover of the problem) would have been hot spots in the F/W that cannot be ground out during normal resurfacing. We have researched this using a NuLine TH134 hand held hardness tester and a really sharp drill bit. The baseline of the casting is about 250-260HB and in the hot spots it is 500-600HB. This is where the drill comes in, try drilling into the non friction area, no problem, now try in the hot spots with the same pressure, it ain't gonna drill. The Cummins Dodge F/W can be a perfectly good looking reground F/W and be carrying the cleaned up hot spots and these hot spots become HIGH spots because they take up more volume due to the transformation into a hot spot shortly after reuse, resulting in chatter. We have measured these before and after resurfacing, they do not go away, they just look better. I do Clutch 101 seminars in the field and the techs ears perk up cause this is the same problem in brake with hot spots. We also consulted with a senior engineer at our sister company Webb Wheel, we are both members of Marmon Corp. he gave us an earful and eyeful about these invisible hot spots.



Good luck, please keep us updated.

The above is probably one of the leading causes of erratic, "chattering" clutch engagement, combined with driveline looseness.



I was surprised when one of this boards leading authorities on vehicle mechanics was commenting on his experience with a particular brand aftermarket clutch - and mentioned that after a period of use he pulled the clutch and flywheel, and found seriously uneven wear on the flywheel - actually DOUBLE the wear depth on one side of the circumference compared to the other.



He blamed that uneven wear on the clutch and the material it was made of - when to me, it was clearly an issue with the variance in surface hardness of the flywheel itself, NOT an issue with the clutch, since it's pretty much a physical impossibility for a clutch to SELECTIVELY wear specific areas of a flywheel or pressure plate unless other factors as covered in the above quote are at work.

Gary-K7GLD I will be in Portland, Eugene and Spokane 8/6-16.

Welcome to Oregon - too bad that's so far from here in Eastern Oregon - it would be my pleasure to meet up with you!

 

[GCroyle]

F/W Condition

We will never know how many clutch issues are flywheel based.



We dealt with one Mitsubishi that we personally put #5 in at 47,000 miles. Short story, the first three were RUINED by the midlife crisis owner who had no clue what to do to correctly engage the clutch, but at #3, the "techs" used a buffing wheel to "resurface" the F/W, yes it was a disaster. I have attached a full write up on it below, makes for sone clutch humor. By the way, the next "techs" #4 ruined a brand new Mitsubishi F/W by not cleaning it correctly.



I have a Friction Zone write up on the Mitsubishi (PDF's) and two write ups on F/W hotspots. They are too big for attaching. I use them in my clinics, if anyone would like to read them, send me a PM with your request.



Gary-K7GLD PM sent.

 

[amsoilman]

I've had my new clutch (OFE) in for a couple weeks now. That thing it ungodly jumpy. Empty it's fine, but even with just an empty trailer it's a chore to backup and not so fun starting out in first. With a full load (35-40K) it's almost impossible to backup. I find myself getting it started and then just popping the clutch. I thought I figured out a way to drive around it, but that still doesn't work. Once I'm moving and shifting everythin is fine and dandy. It's just first and reverse that are awful.



Will it get better with a few more miles (about 1400 so far) or do I need to start looking for a "fix". I can't keep going the way it is, I'll break something for sure.



The clutch and bearings were all that got replaced. No upgraded hydraulics or replacements were done.

Mine was very similar to yours in the shifting as well as the take off, but I don't pull extremely heavy loads either. I changed mine out after only a couple thousand miles, and it is now very smooth engaging. I too just couldn't live with the way that OFE engaged!



Wayne

 

[PC12Driver]

Mine was very similar to yours in the shifting as well as the take off, but I don't pull extremely heavy loads either. I changed mine out after only a couple thousand miles, and it is now very smooth engaging. I too just couldn't live with the way that OFE engaged!



Wayne

You're still running an OFE or did you try something else?

 

[Cattletrkr]

It's been a busy week here and I think i've had a bit of a brain fart. Yeah, it's the same problem as i've had the last couple months with the old clutch. Feels a little different, but it's more or less the same. Not sure why I'd think it's the clutch causing it. Maybe 'cause the clutch didn't fix it???

Like I said, things are kinda crazy here so it's gonna be later next week before I have time to look into things some more. I think I'm gonna have the dealer put the SBC slave in and see what happens.

I've checked over the driveline a couple times since this started a couple months ago. Nothing excessively loose and no binding in the joints when they're hot... at least not that I can tell with the shaft stil in place.

Carrier looks good.

Again, thanks.

 

[hotram03]

Did you not get a new flywheel with the clutch? I thought S. B. was putting a new flywheel in some of there kits now? Mine was alittle like what you described but after use it got alot better. The reverse thing I believe thats a NV5600 thing, mines always done it and friends I know say the same thing.

 

[Cattletrkr]

Carrier looks good.

Well whattya know. From the rear the rubber looks fine, from the front not so much. The bearing is good but the rubber is getting pretty ripped up on a couple corners. Ordered a new one this afternoon. $150 and I can't find one online anywhere.

Talking to the service manager and he said the difficulty shifting is most likely from a synchro issue. Then a tech who was standing behind him smacked him on the back of the head and said, "no it's the slave". So they're getting the kit from SBC.

I'll keep ya posted.

 

[Cattletrkr]

Did you not get a new flywheel with the clutch? I thought S. B. was putting a new flywheel in some of there kits now? Mine was a little like what you described but after use it got alot better. The reverse thing I believe thats a NV5600 thing, mines always done it and friends I know say the same thing.

I think the new flywheels are for the G56 to replace the dual-mass crap.