Hey Guys, My first official post after lurking around for a few years. My truck has lost all forward and reverse motion. I'll explain what happened.

I was taking my dad to the airport driving around 60 miles an hour with the cruise on and i noticed the trans dropping out of OD quite a few times then it stopped. 2 mins after i encounter a slow moving car and decided to pass. ive been warned about the 4th to 2nd downshift being hard on these transmissions but thats exactly what happened. i hammered it down to pass, she dropped down into second and accelerated like normal and then slipped like crazy it hit redline or rev limiter and it scared the **** out of me, i let off and it grabbed again, almost like having a clutch engaged or disengaged ,and went back to cruising speed.

3 mins later i dropped dad at the airport and got out to check underhood. there was a normal amount trans fluid on the stick and a little discoloration but nothing crazy.

I hopped back in the truck, fired it up and i now have a noise coming from trans area and it feels like im driving a stalled truck now. really have to get on the gas to initiate movement.


driving home i lose what seems to be 2nd through 4th, so i had it towed home. i could still drive it into the driveway just at a standstill speed though.

today i fired it up and it wouldnt move at all, nothing whatsoever

ive been stuck at work for the past couple nights so i havnt had time to look at it, but i was curious about throwing it into 4wd for ***** and giggles to see if it would move.

low and behold it did, threw it into 4x and forward and reverse worked again.



SO: does this mean i broke an output shaft ?
could i **** the output shaft and the trans at the same time ?


thanks for any help beforehand. this is my 8th night shift working 12's and im trying to figure this out.

if all else fails ill order a Level 7 4l60 from FLT haha

Dan.

 

It wouldnt be your output shaft if it works in 4wd. Will it shift through all the gears in 4wd? If so, Id look to the rear end. Do you have the stock rear? G80?? If so, thatd be something to check.

With any decent amount of power, this is what happens to G80's

 

Ok Scratch That. I just got up and took it to the store for a late night snack.

it seems when cold it will still move regardless of 2 or 4wd

i started it up in 2wd and put it into reverse and it backed up, put it in drive and it started forward. diddnt give it much gas but it accelerated on its own soon as i gave it some gas to accelerate it started slipping again and i put it in 4x to test that theory again and it still slipped.

when it was moving the rear end diddnt have any noticeable sounds and still moved forth so i think it should be ok but you never know.

this is still the stock 4.8 with an intake and a set of headers so its not like im putting any amount of huge horsepower through it.

stuff like this boggles me, i guess it may be time for that FLT after all

Dan.

 

yeah, cough that up to a dead transmission. clutches, pump, whatever...poo'd out. Check your fluid and see if anything looks out of the ordinary, nevertheless sounds like the trans has got to come out.

 

Dan I think your issue is the fact that the filter is filling up with debris. What happens is when you shut it off the crap in the filter falls to the bottom of the pan. Then you fire it up and it sucks right back in there. The time that it moves ok is limited to how long it takes for the filter to plug back up.

It definitely sounds like your trans is on the way out. Drop the pan to do a visual inspection. Then let us know what you see. Pic's are always good if you have the means to do so. Vince