Violent Shudder on Takeoff

[Backwoodsballer]

Hi Everyone,

Im looking for some advice here.  Recently i have developed what i would describe as a violent shudder when taking off from a stop.  My setup is 350/TH350, 203 converted to part time.  The shudder feels like wheel hop, the whole truck shakes when i take off, the more throttle i give it the worse it is.  I dont mean that it is shimmying on take off, i mean the WHOLE TRUCK vibrates like im having significant wheel hop.  If i take off on a down hill or flat ground where i can softly accelerate then there is no shudder feeling at all.  It also only has this issue when im taking off, otherwise the truck drives fantastically down the road.  Recently i did try taking off by manually putting the truck into 1st gear and i did not notice any shudder, it seems like it might only be happening then the truck is in "D".  There is a notable "groan" when im at highway speeds but no vibrations are felt, the "groan" is constant from about 60mph and up.

I do believe the truck has a shift kit installed as well since the shifting can be extremely hard, if im light on the throttle then its buttery smooth but the more throttle that is applied the more jarring the shift is.

Here are the things that i have inspected:
- All Ujoints are good (Brand new Tom Woods Drive Shaft was installed a few months back)
- Motor Mounts are new
- No Visible cracking at the trans mounts
- No Transmission Leaks
- Transmission Fluid Level is reading perfect and blood red in color
- No notable Pinion slop
- Vacuum to the modulator is solid, although i ordered a new one as there was hints of fluid in the vacuum line

Im thinking it might be the torque converter (i am unsure what converter is currently in the truck), or the TH350 might be in need of a rebuild but i wanted to pick your brains on these symptoms im having.  Its interesting that is just popped up out of the blue, it was driving perfectly one day and then the next its vibrating / shuddering violently on take off.  In my research i haven't come across anyone posting about a shudder this bad.

[ehjorten]

Could be your forward clutches or it could be a worn out governor. By putting it in low gear and taking off, if I remember correctly, the only thing that is holding in low is the low/reverse band. So very likely you need to get someone reputable to take a look inside your transmission.

[Backwoodsballer]

Update,  I took it out today and stopped on a hill for a better test.  I shifted manually to 1st and mildly took off, it shuddered all through 1st gear.  Then I manually shifted to 2 and bang the hard shift, then what felt like a slipping clutch all through 2nd gear.

Does this change anything or help with diagnosing?

Sorry, I’m not used to automatics at all. 

[ehjorten]

Doesn't really change that something is wrong internally with your transmission, and it needs to be gone through.

[Backwoodsballer]

Okay thank you, i just wanted to check with someone else to make sure i wasnt missing anything obvious.  Ill pull the trans next and drop it off.

[Backwoodsballer]

I just wanted to update the thread,  I had the transmission rebuilt and the clutch packs were smoked.  There was nothing left to them at all, they were metal to metal.

Hoping to slip the transmission and transfer case back in today.

[ehjorten]

Great news! Always a bit hard to swallow when you have to pay those big bills to get something rebuilt, but sounds like it was definitely needed.

[JohnnyPopper]

Yes, always glad when members follow up with results, Thanks!

Re: Automatic transmission- Keep them clean and they go and go!