I keep debating on whether or not I want to potentially screw up a good thing by installing some injectors to help with towing a little and possibly gain a mile or two. I have no intentions of anything over 75 hp sticks and I was even thinking of keeping it simple with some RV275's. But this isn't a "which injector is best" thread. What I'm wondering is how much HP has anyone put on the OEM 5 speed clutch before it started to slip? I dont really want or have money to justify purchasing a new clutch. So for this reason I have done nothing but if I could get away with some RV275's and keep from changing the clutch then that might work for me.

100 HP injectors are a bit big for MPG purpose...As for the clutch its most likely going if its slipping. So the best thing you can do now is put the money away for a new clutch and ready ready to yank it out. Because a clutch should never slip.Quick question is there any fuel leaking or oil leaking around the bellhousing?

Have you checked for any codes?

--- Update to the previous post...

test test test test test test test

Possibly...??? . Took a couple pics... Oil appears to be coming from the oil pan gasket on the sides of the block.. But I don't know about near the rear. I could snap another pic of the 'crevice' between the oil pan and the bellhousing, too. Should that whole bellhousing be clean and dry? I've not yet got to paying special attention to this area of the truck.

Looks like you may have a rear main seal gone. If it is leaking bad enough, you may have also discovered why your clutch is slipping.

Is there a way to quantify 'bad enough'?

Have you checked for any trouble codes? Your underside looks similar to mine. I dont see any oil droplets hanging fron the bell housing, just some streaking like possibly the wind is blowning it onto the back of the engine from a leaking oil pan. I had my rear mainseal replace about 10 months ago along with the clutch, but it looks similar to yours and I do believe mine is coming off of the oil pan. When you say it is jerking are you sure it is not the engine cutting in and out under heavy throttle. I have had bucking in the past, but that was engine/injector pump and not clutch related. Just throwing that out there. If your rear main seal is putting oil on the clutch that could be the cause too.My stock clutch held up to everything I gave it except the rv's. I installed them after replacing the clutch, but pulled a 15k# 5th wheel wide open in any gear with no problem.

Not lately, no. The truck gets driven about once a week, so I haven't REALLY focused on the problem yet. In the meantime, had been digging in websites and forums looking for my symptom. I can surely check for codes, though. I'll take it out extra this weekend and play footsie with the pedal. Did you throw any when you had your engine/injector pump issue, dripley? Out of curiosity so I can keep my eye out. This truck has a tapped pump wire and velcro on the fuse box, and hitch marks for a 5th wheel in the bed. I do not know the previous owner(s) or past of the truck. It was a trade-in at the dealer I bought from. So who knows what the clutch has been thru. I found some threads on the rear main seal, so will check out those, too.

Are you experiencing this slipping/jerking upon engagement or under load? by load i mean heavy throttle.

Under load. Every time. No jerking when engaging. When it first showed up, it would jerk/buck/lurch in 6th at WOT only. It seems to have gotten worse to where it will jerk at non-WOT points in 5th and 6th. Sometime it will lightly jerk while cruising at 1400 RPM. So far, the only time I can MAKE it happen on command is WOT, just after shifting into 6th.

Under load. Every time. No jerking when engaging. When it first showed up, it would jerk/buck/lurch in 6th at WOT only. It seems to have gotten worse to where it will jerk at non-WOT points in 5th and 6th. Sometime it will lightly jerk while cruising at 1400 RPM. So far, the only time I can MAKE it happen on command is WOT, just after shifting into 6th.

That is making me think it is a vp/fuel problem. Mine starting doing the same thing though maybe not as often. I had my truck checked out at a fairly reputable diesel shop in Maryland. They never could figure out what was wrong, except low fuel pressure. At the time I did not know about the fuel problems with these trucks, but read about it later. Get your codes checked and see what you have. Do you have a fuel pressure gauge? if so what pressures are you seeing at idle and wide open throttle under lo

I checked the codes last night with the on-board reader... This was with the truck not moving, engine not on. PCU:0500 - No vehicle speed sensor signal1694 - No Bus message received from companion moduleECU1693 - DTC detected in companion moduleYes I do have a fuel pressure gauge. It's tapped into the feed line from the AirDog to the VP, just before the fuel enters the VP. Idle ~ 17 psi. WOT ~ 14 psi. During the jerks while driving, I have checked the fuel pressure gauge... And there is no noticeable drop that coincides with a jerk. But... I had found air in this gauge line before, so I'll check that again and see if we're getting air in the gauge system that could dampen the response to the fuel gauge. Using the truck today to do some yard chores.. So I'll see if I can get some instigate some jerks and see if codes change.

I checked the codes last night with the on-board reader... This was with the truck not moving, engine not on. PCU: 0500 - No vehicle speed sensor signal 1694 - No Bus message received from companion module ECU 1693 - DTC detected in companion module Yes I do have a fuel pressure gauge. It's tapped into the feed line from the AirDog to the VP, just before the fuel enters the VP. Idle ~ 17 psi. WOT ~ 14 psi. During the jerks while driving, I have checked the fuel pressure gauge... And there is no noticeable drop that coincides with a jerk. But... I had found air in this gauge line before, so I'll check that again and see if we're getting air in the gauge system that could dampen the response to the fuel gauge. Using the truck today to do some yard chores.. So I'll see if I can get some instigate some jerks and see if codes change.

The p500 just means you spun your tires somewhere unless you speedo is not working. Then the sensor is probably bad. The 1693 is just a companion code letting you know there is a code in the other computer. The 1694 I am not sure of, if your cluster is working properly . Might have been there if you did not have the switch on while checking the codes, someone else might have to correct one on that. Electronics is not my strong The jerking you are describing is very much like what I experienced before changing my VP. I heard it described as bucking when i experienced it. Under load and it was like you swithced the truck on and off for a split second. It was intermittant and ususally happen in 5th or 6th under load. It is briefly dexcribe here http://www.bluechipdiesel.com/vp44_diagnostics.html about 3/4 of the way down, red header, under intermittant skip. Google bucking vp44 and you can see some other descriptions of what i am speaking of and compare to what you are experiecing.

Hmmm hmmm hmm... So I did a search as suggested and found one thread in particular... Very interesting. Got me thinking about when this jerking started... And I can say it DOES happen during winter time.. But I CANNOT say if it happens in warmer weather. I can't remember if I noticed it last summer...And it did happen in the fall. That Blue Chip explanation seems pretty close too. Thanks for the link.. I'd seen a Blue Chip VP44 diagnosis article, but it was apparently a different one. Anyways... This threads seems VERY close to what I'm experiencing. (http://www.newenglandturbodieselpower.com/Forums/archive/index.php/t-923.html) So luckily, I've got a high idle mod harness on my desk at home right now... With an added switch for IAT fooling (MPG fooler, thanks Mike for the idea and wiring diagrams for the high idle mod!!) I'll be adding this to the truck soon, and will check of the MPG fooler helps the jerking. Dave, when you replaced your VP... Did your jerking cease?

Yes it did. But as i remember it was some what reduced after I installed a booster pump to get my fuel pressure up from the in tank one dodge installed after the oe failure. The intank was only giving me 1/2 psi at wot about a year after install. I had her in a shop trying to figure out what was causing it. I also had dead pedal issues(driving underload and the engine would go to idle with no throttle response. had to resart to get throttle response). The higher fuel pressure helped with both problems but did not eliminate them completely. Since the new VP and lift pump the issues have dissapeared completely. I am thinking the low lift pump pressure was the original cause but had already damaged the vp to where a new lift pump would not over come the problem now in the vp. Understand at this time(5years ago) i did not know squat about these trucks fuel supply problems or electronics. Shoot I am still learning.As far as the thread you referenced,my problem was pretty much like Sooter's, 5th and 6th gear under load and it would do it. I never paid any attention to boost pressure when it happened, but it would happen on the highway cruising empty or under load. More so under load as i remember.As far as what BlkRam1 states, I only had the Banks stinger plus on mine with a booster pump and stock injectors. The only extra fuel i could have been getting would have been thru the Banks. Maybe the IAT fooler will help. I dont know enough about them to have any opinion.

I see. That's a good point about damaging the injection pump before it totally fails. Yet boosting the lift pressure and the symptoms improving. Recalling the papers in my glovebox that came with the truck, there were service records for a clutch replacement... But nothing that I remember about fuel system work. So thinking about that, I know someone played with a fueling box on the truck (I had mentioned before the pump wire is tapped and old velcro on the fuse box)...But who knows if the box went on before the AirDog was installed. And thus, who knows if the pump got damaged, or has had a full supply of fuel from day 1. I've monitored boost levels while this jerking was happening. If I crreeeeepppp up on the throttle into 2000+ rpm with boost 20-25 psi... I can get by without jerking. But if I run up fast, the jerking comes on strong and is worse at high boost... But that is also highest load (so again... clutch or fuel flow?). I've seen it do it at 7 psi at 1400 RPM though too. It's never been 100% consistent at coming on at one engine point. I've never heard of the '24V timing shutter' that BlkRam1 speaks of... So I'll have to look into that as well... (the list is growing). But it would be an interesting data point if an IAT fooler makes it go away. After your story though, that IAT fooler make me a bit leary about covering up an issue.

As I remeber mine only did it out on the highway cruising in 5th or 6th, depending on whether I was towing or not. It would do it holding steady throttle or heavy throttle. Just like you had a switch you could flip on and off, just a split second. Might go for month and not do it and then do it several days in a row. Never a stutter just once then again a few minutes or longer later it would do it a gain. I did experience some cutting out or stutter if I left a fuel filter in to long. I changed the filter and it went a way.

All of this on mine occurred with the oe clutch, the Banks system and I never felt it was the clutch slipping. No rpm change, but the event would be so quick I am not sure anything would have a chance to change. Just seems like it would be hard for the clutch to slip for a split second and re engage that quikly without some normal sign of it slipping, like an rpm increase. I just changed the oe clutch about a year ago and it still was not worn out and the bucking went away completly with the vp install a little over 2 years ago. The AD went on 1 year ago. My pump is tapped also.

--- Update to the previous post...

http://www.cumminsforum.com/forum/98-5-02-powertrain/490877-random-cutting-out.html

here is another thread on the same thing