alright guys and gals, so i had a short little discussion about this happening when i was asking about turbos, so i thought i would post a thread about this. The "shuddering" has been getting worse in the past week, so here's what's going on: the truck shudders at a constant pace now, even on flat ground, and is worse with the OD locked out and TC locked up around 28-35, so it's worse in the lower RPM range, from 1000 to around 1500 about, not exactly sure about the higher number. i noticed today that when it shudders, the tach flickers up and down slightly, so i have a feeling that the TC is slipping due to something outside the TC? i was told that it could be a voltage regulator and to even put on a noise filter. as you can see in my sig, i had my transmission built, and that was back in this past September. i took it back to the transmission place that i had it built at, and he said that it felt like the engine was misfiring and that an injector or more were going bad. there are so many different things to look at, so i'm looking to you guys and gals for advice to narrow down the problem. i don't have my fuel pressure gauge up and running yet either... any help would be greatly appreciated, and i'll answer all of your questions!

Thanks everyone, I really appreciate it!

 

Mine does a tiny little bit of shudder at the conditions you mentioned. It did it a lot before I repaired my fuel tank module (I had aerated fuel)

Easy way to check: Take a piece of 10mm (3/8") id transparent hose and a fuel canister, slide the hose over the water drain hose on the fuel filter, open the water drain and have somebody bump the starter- if there are a lot of bubbles you have a lot of air in the fuel and that ain't good.

On the 24V the injectors don't fail too often, especially not in a way that creates random misfires.

AlpineRAM

 

Suncoast has a good rep but perhaps the rebuild shop did a bad job. Did they set the line presssure correctly? Anyway, line pressure between 1000 and 1500 RPM is not enough to keep the lockup from slipping when you create good power. Rule of thumb is DON'T make power until the engine is turning better than 1700 RPM (unless your tranny is decently built). Anyway #2, don't trust the tranny shop that built it to point their finger at other issues when their tranny shudders.

 

the transmission shop i had it built at is a very reputable shop. they even built my dad's allison and did a great job.

is there any way for me to check the line pressure myself, or even adjust it myself, for that matter?

 

Even a good shop can make a mistake. They should be willing to check the line pressure for you to rule out the most common cause of shudder. Of course, the TC seals could be going bad, too.

I've never done it, but if you do a search you can find threads on the subject. Or post the specific question. Five years ago when I asked the question there were no answers but the knowledge base is bigger now.

 

my check-up is coming up soon, so i'll have them take a look at it when i take it in. i really appreciate the help guys. this shuddering is really getting on my nerves! tomorrow i'll drain the fuel filter and check that out AlpineRAM and get an update.

i checked the tranny fluid the other day. i pulled the stick, wiped it off, then checked it again and there were bubbles in the fluid. is that normal?