Competition Truck "shudders"? under acceleration

[Smokewagon]

I put a new Con OFE in a couple of months (5,000 mi. ) ago, and ran the normal "wear in" period. After about 2,000 of the 5,000 miles on the clutch under acceleration the truck acts like it shudders "sometimes worse than others" under WOT when shifting to 4th, 5th and 6th. At 60 mph, it acts like it's slightly vibrating, as if a tire is out of balance. I'm confused, I checked fuel pressure and it's adequate. I put the clutch in right, surfaced the flywheel FLAT on a blanchard and that clutch wasn't my first rodeo. So..... what in the heck is going on? I haven't pulled out the DDII's and checked pressure yet but there has got to be a simple explanation for this. It's really weird. Sometimes it seems to be worse than others. Under WOT through the first 3 gears it acts perfect. Anyone got any ideas?



Thanks, Dave

 

[HoleshotHolset]

Maybe when you disconnected the driveshaft(s) they didn't go in with the same 'phase' as before... .



I have seen very few isolated cases where changing how the U-joints were phased with the transmission and differential yoke(s) made a little bit of difference.



It's worth a shot and is cheap to try... . just for grins and so forth.



Matt

 

[R.E. Miller]

Idea...

We had a real weird situation with a dodge that was about the same year as yours. Watch your temp gauge, and see if the shuddering only happens when you go over 190*. We had a truck that we thought had fuel system problems because of a "miss/shudder" that only happend under load and when operating temp was reached. After a lot of time, it turned out to be the thermostat was faulty, the thing opened and closed rapidly, causing the racket. None of us would have bet on it, but you learn new things everyday.



Russell

 

[Smokewagon]

I appreciate your thought/idea! I took my truck to the dealer today, they hooked the diagnostic computer on and absolutely no codes were set. They said that this wasn't the first complaint that they have had regarding my description. Also, I forgot to mention that a couple of times under acceleration, the truck would completely shut down for an instant then before you could get your foot out of it, it would come back to WOT. They said, the heck with it. They just ordered me a new 44 and lift pump. Obviously, a good dealer is worth doing business with I am supposed to get it back tomorrow. (They are air freighting it) I know it's unbelievable:--) I can't wait to see if it solved the problem. I'll keep the results posted.



Dave

 

[RHARVEY]

This may be a dumb question... but when it done its shuddering. . do you know what the fuel pressure was????



Rick

 

[HoleshotHolset]

FWIW:



The 2002 trucks without the CAD (Central Axle Disconnect) have had MANY complaints about odd vibrations - most dealers have been clueless about it too... .



Matt

 

[Smokewagon]

Matt,

Forgive me, what's CAD! I got the truck back last evening and as far as I can tell, everything sounds OK with the 44. I didn't have a fuel pressure ga. installed just a boost and temp ga. As far as lift pump pressure, it was 15 at idle, 10 at WOT. This was checked by the tech at the dealership. (They gave me back my old lift pump, 10K mi. ) I took the EZ off so that I wouldn't put the dealer on front street. (He knows of it and doesn't care) I have been waiting to put the comp on untill I figure out the problem you know, the wire piercing deal BTW... ... ... My hat is off to the dealer for the support and speedily need of my attention, I don't know if being a business link customer had anything to do with it or not, but I can honestly say that I was treated like a king!!! I know, this is probably unusual compared to others and how they have been treated. And a HUGE thank you goes out to KEN JONES at DIESEL PERFORMANCE in Ogden Utah for overnight air freighting my big banjo bolts and fuel lines for me. He has been unbelievably courteous, informative and knowledgable regarding my bombs. Heck I'm 1200 miles from him and I feel like we have been lifetime friends. What a guy! He didn't have to leave his shop, make a trip to UPS at 2pm and guarantee me that I would get it by 10am the next day. He even sent it directly to the dealer so that there would be no mix up in destination. The dealer even installed the lines and banjos for me while I was there so that I wouldn't have to. . Ken is sending me a pusher pump, fuel ga. and AFE mega cannon as we speak. The 40 and ATS 3pc. manifold will be on the was as well. I don't know if the "shuddering" is still there as bad as before, (due to the EZ being off and only DD 2's) BTW, I wonder if just the DD 2's make a little more racket than std. injectors



Dave

 

[RHARVEY]

What does the truck(any 24v) do when under WOT and the lift pump is not suppling enough fuel to the 44?????



Rick

 

[HoleshotHolset]

CAD - all it does is disengage the passenger side axleshaft from the differential. Since the front differential isn't posi... . the other shaft turning will not cause the differential or front driveshaft to spin. Dodge (in their infinite wisdom... ) used a vacuum actuated CAD... . GM's used vacuum and electric (both heated element and electric servo actuated... . ).



The CAD is good in that it keeps stuff from turning that doesn't really need to turn when the truck is in 4x2... . but it's not the best way to skin a cat. They have their problems.....



The 2002 trucks without CAD have had many vibration type problems. I even know one guy that got rid of a really nice brand new truck because it was so bad and D/C couldn't fix it (it's a sore subject for him... . for obvious reasons... ).



Hope this clears things up a bit... . if not I'll continue...



Matt