This just started. I was pulling a fair sized load in the Ozark hills of Missouri this weekend and every time I gave it hard throttle - the truck really shuddered and shook at about 90% throttle. It almost felt like it was "wheel hopping". At 70% or 100% the shudder went away. I know I wasn't breaking loose the back tires and spinning as it was dry and I was going over 65 (so the transmission was locked in overdrive). Would this be a torque converter problem? It is the stock transmission and I have about 150K on it.

I dread thinking the transmission is going out but would love to replace it with a Suncoast or DDT. Thoughts?

 

Sounds like it. I just did the same thing. Check your trans fluid and it is likely burned. I pulled the trans and got a new torque converter and Suncoast valve body from Gus at Farmboy's Diesel Performance. http://www.farmboysdiesel.com/ He used to advertise here but haven't seen it lately. He told me to just change out the converter and valve body and run it if the rest of the trans seemed OK. I had 130k on mine. I did that - removed the check valve from the cooler and adjusted the bands. My oil was fried before and now is fine. I assume I have around 10000 miles since the change. I also ordered the deep pan for extra cooling.

I had the shuddering here also. One thing to do is to get it done before it totally shreds itself and sends metal through the transmission. He said he had another friend who also had done the same thing and has put on a lot of miles with no problem. I also went to DexronIII-Mercon for a solider shift.

 

Glen-K I was and am worried that if I continue to drive it, I'll take a chance of permanent damage (when it shudders, it really shakes or bounces the whole truck until I let off the fuel). Anyway, thanks for responding and I think you are right. I'll check out the fluid tonight. You have the 48 series transmission and I have the 47re I belive.

Since I don't pull much or often, I hope I can put off the investment for a little bit. I can't see just doing the torque converter without going and upgrading the transmission (valve body only may be the way to go but I'm no transmission expert for sure). It is paid for and figure an investment in a transmission on a truck I love is better than payments on something new.

If this thread doesn't get moved - I'll open one in the 12 valve engine and drivetrain catagory.

 

It could also be starving for fuel.
Change the fuel filter and/or check fuel pressure.

 

Infidel - I'd agree but it seems to stop when I go to the floorboard with the pedal. However, I'll see if I can rig up a fuel pressure guage that I can monitor when I am driving. (I'd love to have a permamant one in the cab but understand the 12 valve motors don't usually have too many fuel pressure issues (gleened that from this forum - hope I am gleening correctly).

 

If you are going to try to run it a bit then you may want to change the filter and bring the pressure up a bit - I slowed down the shudder on mine for about a month but still burned the fluid again in that time. I went 3 turns to raise the pressure about 10 lbs. When you push it to the floor and stop the shudder you are raising your line pressure possibly stopping it from slipping. This is only a band aid. Here is the pressure info from
http://www.dieseltrans.com/phpBB/viewtopic.php?t=68