One the truck in my sig, it has only happened since I added exhuast, EGR blocker and fingerstick, and PPE air box mod.

When towing 9000 lbs, up a decent grade, usually when in 5th gear, but now seem to notice it in 4th a bit, the truck gets a shudder, that turns very bad when going up the grades. If the grade is too steep it just shifts into 4th and seems to hold fine, only on the medium grades where it has enough power to hold 5th.

I am sure it is slipping or something, but for two reasons I am second guessing myself. One is there has never been a check engine light and it has done this 5 times now. At first I would back out of it, but now I hold it there hoping something will happen and then I can fix it. Two, the engine or more so the exhaust changes sounds just before the shudder comes on.

I tow with the Evo on #2. For testing I tried in on level 1 and stock with no shudder, but on level 3 it is very bad.

Help?

Sounds like too many :horsey: for the tranny.
When was the last time you service your tranny?
Spin off the exterior filter on the tranny & look at the mag. Let us know what you find.

Truck only has 19,000 km's or 20,000 miles. Fluid is still brand new looking and never is hot at all. What I want to know is "is it possible to slip it, either torque converter or clutches, without a CEL"?

Would the magnet have any metal on it if only the clutches slipped a couple times?

Yes, you can slip the tranny without getting a CEL. I'm not sure what the make up of the clutches are but I would be interested in seeing what is attached to the mag @ the filter. If I were you I would take all modes off that have to do with HP increase drive it a while, then take it in for warranty repair. Good luck & keep us posted.
Mike

Sounds like too many :horsey: for the tranny.


x2

I have spoke to 5 good transmission people now. Not one of them think it is the tranny as it does not have a CEL.

One other avenue I am thinking may be the cause is I have eliminated the botom heavy duty thick rebound spring in the rear suspension. My truck was very rough when empty, and really bad when towing my trailer. It made it buck and jerk like no tomorrow. Once I flipped the rebound spring over, it rides like a car. To hold the extra weight I added air bags. Rides like on a pillow when towing now. Hitch weight is only 900 lbs or so on this trailer, any heavier and it would have probably rode smoother and I would not have had to flip springs. I will try and test this on weekend.


Only weird part is the noise it makes before the shudder comes on. Maybe there not related.

Crossing my fingers tranny is cool, then Transgo here I come...

Yes, you can slip the tranny without getting a CEL. I'm not sure what the make up of the clutches are but I would be interested in seeing what is attached to the mag @ the filter. If I were you I would take all modes off that have to do with HP increase drive it a while, then take it in for warranty repair. Good luck & keep us posted.
Mike

Only issue here is when it is set to stock, there is no shudder, so no need to do warranty or any repair, according to dealers. I have to aggree with where they are coming from.

x2

But, but, .... but I like HP

I have slipped trannys before without the cel light coming on. And some of these were shakers.:eek: Meaning high gear/high torque tranny chatter. Isn't the torque on a diesel engine great!

I have spoke to 5 good transmission people now. Not one of them think it is the tranny as it does not have a CEL.

One other avenue I am thinking may be the cause is I have eliminated the botom heavy duty thick rebound spring in the rear suspension. My truck was very rough when empty, and really bad when towing my trailer. It made it buck and jerk like no tomorrow. Once I flipped the rebound spring over, it rides like a car. To hold the extra weight I added air bags. Rides like on a pillow when towing now. Hitch weight is only 900 lbs or so on this trailer, any heavier and it would have probably rode smoother and I would not have had to flip springs. I will try and test this on weekend.


Only weird part is the noise it makes before the shudder comes on. Maybe there not related.

Crossing my fingers tranny is cool, then Transgo here I come...


Was not the leaf springs, back to the drawing board. Either drivline angle, or something is weird. I still don't think it is tranny, but is starting to sound weird in some 2-3 shifts, and even one time from 3-4.