78 chevy 4x4 turbo 400 loud bang now won't move

turfpro

Junior Member
Location
CDA Idaho
I own a 78 chevy 4x4 turbo 400 & np203.I was pushing up a berm with heavy snow and it made a loud bang and just stopped moving.
I assumed it came out of gear as it sounded like that but louder.
It had popped out of 4 wheel drive from my dog putting weight on it a few times and I really thought it just popped out of gear.
So, I shut it off and pulled it back out of 4 low but if I remember correctly, the 4x4 shifter seemed to move freely.
I then started it and nothing in and gear or any gear transfer case.
I went under assuming broken ujoint and again everything seemed find.
Transmission fluid was find and no noise at all when I start it and shift gears or and 4x4 position.
It feels like it's shifting onto forward and reverse but won't move.
I had a local auto shop put a used transfer case in it and it's exactly the same.
I can start it and put in any gear and no abnormal noise.
What the heck is wrong.
I don't have anymore extra money right now to waste.
Shops around here just want to sell you a full bullet proof tranny and transfer case.

Help Please.
Jerry
 
OP
T

turfpro

Junior Member
Location
CDA Idaho
Check your bolts on the torque converter, may have sheared them off. But sounds like you destroyed the transmission if you already replaced transfer case. You should beable to find a used 400 or 350 for pretty reasonable.
Would it feel like going into gear?reverse to 2nd or 1st you feel it and kinda hear it.
It made a pretty loud band, like if you're under power when it pops out of 4 wheel drive.
I already look the bottom cover off bell housing and it was fine.

Something had to have broke.
I'm not a tranny guy but good repair mechanic.
I repair most all my equipment.

Never really got into tranny repair though.

Thanks and much appreciated response.



Anyone else.
 
OP
T

turfpro

Junior Member
Location
CDA Idaho
There's a guy close that has a 77 Chevy with turbo 350 and I think 205 transfer case.
He only wants 500 for it all.
He bought it to put tranny and transfer case in his suburban and he said it was too short etc.
Also the yoke on the 350 and 400 I heard are different.
I was thinking about buying that truck and using the turbo 350 and transfer case as they are already out of it.
But what about the swap in my 78 chevy with turbo 400 and 203 transfer?

Appreciate the tips and help...
Jerry
 

Randall Ave

PlowSite Fanatic
Did you drain some fluid from the transfer case to see if any metal is in it? Drop the pan on the tranny and check that. My money is on the transfer case. There's no noise at all?
 
I would of bet dollars to donuts was not the transfer case when happened to me. Especially when it just had one over the GM rub factor. Suppose to give you some kind of indentation. Shimmy etc, did not notice and kept on wailing.

My bad according to my tranny guy.
 

LapeerLandscape

PlowSite Fanatic
Location
lapeer, mi
I own a 78 chevy 4x4 turbo 400 & np203.I was pushing up a berm with heavy snow and it made a loud bang and just stopped moving.
I assumed it came out of gear as it sounded like that but louder.
It had popped out of 4 wheel drive from my dog putting weight on it a few times and I really thought it just popped out of gear.
So, I shut it off and pulled it back out of 4 low but if I remember correctly, the 4x4 shifter seemed to move freely.
I then started it and nothing in and gear or any gear transfer case.
I went under assuming broken ujoint and again everything seemed find.
Transmission fluid was find and no noise at all when I start it and shift gears or and 4x4 position.
It feels like it's shifting onto forward and reverse but won't move.
I had a local auto shop put a used transfer case in it and it's exactly the same.
I can start it and put in any gear and no abnormal noise.
What the heck is wrong.
I don't have anymore extra money right now to waste.
Shops around here just want to sell you a full bullet proof tranny and transfer case.

Help Please.
Jerry
You had a local auto shop put a used transfer case in it? Did you have them check your transfer case when they took it out? Were they sure the new/used transfer case was good? I would go back to the shop and ask if they can take look at your old one to see if that was the problem. Too many people just replacing parts and not diagnosing the problem.
 

fireball

PlowSite.com Veteran
Had this happen many years ago Brake lining separated from shoe spun around in drum and the loud bang was the lining jamming under the shoe against drum. Truck wouldn’t budge
 

Hydromaster

PlowSite Fanatic
Location
406
My only thought is what mine did 20 years ago,the main shaft in the tranny broke clean,no noises,just wouldn't move. Spinning in place.

I snapped a output shaft on a furd when I wuz a kid .

Bang then noth’en. No noise, no visual damage.
 

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