Engine/Transmission (1998.5 - 2002) First time post: South Bend clutch seems to slip

[tsawwassen jim]

I just completed a trip pulling my 9000 lb fiver through the mountains of southern British Columbia. I was suprised by an apparent slipping of my Con Fe South Bend clutch when accelerating in 6th gear. This slipping showed itself as a rapid "grabbing" almost like the engine was missing. However, the engine and turbos were smooth as glass and the grabbing/missing disappeared when shifting to a lower gear. Even mild uphill grades caused the problem. I talked to Peter at South Bend and he indicated that the clutch probably just needed to be deglazed and I'm pretty sure it's deglazed by now. Has anyone had similar problems with this clutch?

 

[Joe Mc]

When Pete mentioned it "probably" just needed to be deglazed - I "think" he was referring to it is probably glazed from the slipage you explain that you experienced and a deglazing would restore the surface. Oh, this might sound like a stupid question but, did you have the flywheel resurfaced before installign new SB clutch? You'd be suprised how many people don't even think of doing this.

Wait a minute this "Slipping" was when accelerating in 6th gear w/9000# trailer going up hill? Sounds like a clutch endurance test to me?

 

[rubberneck]

Wait a minute this "Slipping" was when accelerating in 6th gear w/9000# trailer going up hill? Sounds like a clutch endurance test to me?

No way, that clutch should not slip under those conditions. I do not know the posters mods, but i ran that clutch real hard towing up to 14k and only slipped it once. I was trying to smoke out a guy in a power stroke and went full throttle 1600 rpm with TST/EZ set on kill. The clutch recovered just fine. Nice thing about the full FE, is it will "reseat" itself with just a few miles.



Did it make any noise?? My experience with that clutch is that when i slipped it, it would make a screeching noise. Are you sure it was the clutch?? I am sure if it is the clutch, peter will take care of you. List your mods, but my guess is you dont have enough power to tear it up. I beat on mine for a good long time at HP levels not generally accepted for heavy towing and it did its job admirably.

 

[Bob V]

It might be driveline "shutter". Kind of a rapid load/unload of the driveline. this can be helped on some trucks by a driveline alignment. What year, trans, and bed length is your truck? Check out this TSB http://dodgeram.info/tsb/1994/16-01-94.htm , even if this doesn't match your truck it could still apply, my 2005 does it some when I pull my trailer. Most all clutches will keep slipping once they start until the power is backed off.

 

[tsawwassen jim]

It might be driveline "shutter". Kind of a rapid load/unload of the driveline. this can be helped on some trucks by a driveline alignment. What year, trans, and bed length is your truck? Check out this TSB http://dodgeram.info/tsb/1994/16-01-94.htm , even if this doesn't match your truck it could still apply, my 2005 does it some when I pull my trailer. Most all clutches will keep slipping once they start until the power is backed off.

Bob V : thanks for the comment see my truck profile for my mods. The tsb seems to indicate a problem when launching my stutter occurs when accelerating up a grade in sixth gear and disappears when I downshift. Wouldn't driveline stutter continue on a downshift?

 

[tsawwassen jim]

No way, that clutch should not slip under those conditions. I do not know the posters mods, but i ran that clutch real hard towing up to 14k and only slipped it once. I was trying to smoke out a guy in a power stroke and went full throttle 1600 rpm with TST/EZ set on kill. The clutch recovered just fine. Nice thing about the full FE, is it will "reseat" itself with just a few miles.



Did it make any noise?? My experience with that clutch is that when i slipped it, it would make a screeching noise. Are you sure it was the clutch?? I am sure if it is the clutch, peter will take care of you. List your mods, but my guess is you dont have enough power to tear it up. I beat on mine for a good long time at HP levels not generally accepted for heavy towing and it did its job admirably.

rubberneck: thanks for the reply. My truck is fairly tricked out and should put out 450-500 RWHP when dynoed. However, I was only using rather mild enhancements with a Smarty at level 3 and comp box on 3 when the stuttering occured. I've got about 10,000 km on it since install by Piers and it should be seated by now. I also had a new flywheel installed at the same time. I'm a little disappointed since my stock clutch never did this although I slipped it too many times and that's why I wanted the Con FE. The clutch did not make any noise such as a screech just the stuttering which worsens as power is applied.

 

[CWerner]

I have the 13 inch confe and sometimes at the drag strip it holds great and other times it wont hold at all. One other time while towing a ford focus on a dolly it let loose when I was getting on the freeway. I let off and got on it again and it held.

 

[rubberneck]

rubberneck: thanks for the reply. My truck is fairly tricked out and should put out 450-500 RWHP when dynoed. However, I was only using rather mild enhancements with a Smarty at level 3 and comp box on 3 when the stuttering occured. I've got about 10,000 km on it since install by Piers and it should be seated by now. I also had a new flywheel installed at the same time. I'm a little disappointed since my stock clutch never did this although I slipped it too many times and that's why I wanted the Con FE. The clutch did not make any noise such as a screech just the stuttering which worsens as power is applied.

Just checked out your profile, and you definitely have some power. Got me beat on the turbos, but i am running more injector than you. I still dont think it "SHOULD" slip, but definitely could be. Could be that the combination of the smarty along with the twins (probably spool and make better bottom end than my single) have just surpassed what you can do with a single disc. Did you have all this power at the time the clutch was installed, or did you add afterward? IMHO your installer should have directed you toward a twin disc with those mods. Just my opinion, but there is a reason that i went twin disc. (Mcleod currently on its way out, with a SBC waiting to take its place after 80k of hard miles) The driveline shudder could be a possibility, but I would think you could tell a difference. I get some funny surge type feelings depending on which trailer i am towing, but traction bars took most of it out (axle wrap) Definitely not a chatter as you describe.

 

[RonA]

The BD twins spool very quickly and produce alot of torque. My truck has a very quick spooling set of twins also, and will slip the new FE as well. It is a matter of torque, not horsepower. The FE is supposed to handle 550hp, but only rated at 1k or 1100 torque. Fast spool and a bit of fuel can easily surpass the torque number. If you find a fix, let me know.

 

[J.Keith]

My FE has been holding 1200+ ft lbs for a while now.

That includes a couple of hooks to a sled and some drag racing.

 

[RonA]

Mine slips at 475hp 1100tq.

 

[tsawwassen jim]

Some good observations. However, the problem seems to occur even though I am not punching it. For example, I was driving through the foothills of Alberta heading for Calgary and encountering some mild uphill grades while on cruise control at 100 km/hr (60 mph) when the cc applied some throttle to move up the grade the clutch would shudder until the set speed was reached. This also occured prior to the installation of the twins and DD 3's so I don't think its a excessive power issue. Many thanks for your input fellows I would still like to hear more of your thoughts before I contact Peter at SBC tommorow.

 

[Joe Mc]

Now that there's more info from my first guess (reply) I'd ask Pete if he thinks it's time for more than a single. If the trans has to come out again might as well double up? MHO

 

[rubberneck]

The BD twins spool very quickly and produce alot of torque. My truck has a very quick spooling set of twins also, and will slip the new FE as well. It is a matter of torque, not horsepower. The FE is supposed to handle 550hp, but only rated at 1k or 1100 torque. Fast spool and a bit of fuel can easily surpass the torque number. If you find a fix, let me know.

Agreed 100%. The one time i slipped my FE, I had the stock hx35 on because I was doing a lot of towing at the time and MY B1 tows like doodoo IMHO. I think the only thing that will fix it for you Ron is a twin disc. Smoother engagement (with organic linings) and holds more torque.