Tranny Problems

I have a Turbo 350 from a mid '70s pickup transplanted into my '85 K20. It went from running fine one day to no gears the next. I doesn't engage in any of the gears and then it makes a loud grinding noise when you put it back into park. It ran great and shifted firm right up until this all happened. I dropped the pan and found nothing out of the ordinary, filter was still attached and pretty clean and the fluid looked and smelled like it had just been poured from the bottle. Any suggestions?

 

Converter or front pump issues. Check the converter to flex plate bolts first.

 

A broken axle will cause the parking paw to grind when you try to put the ****** back in park, as everything in the ****** is still spinning.

 

There is definitely no movement through either drive shaft and i can't detect anything turning inside the transfer case either.

 

Doesn't that have a chain between the end of the ****** and the input to the transfer case? If so maybe the chain broke.

 

It is a NP 203 Transfer Case from the same truck the transmission came from and yes, I
believe it does have a chain. Is there a way to check this with it still in the truck?

 

make sure the transfer case is fully engaged into 4x2 or 4x4. if its in nuetral it will free spin and cause the park pawl to grind until the output shaft stops spinning.

 

The chain drives the front axle only.
The rear axle is direct gear driven thru the transfercase...but can be in either low or high range, or in neutral inside the case.

Sounds like your in neutral as the guys say...and that means the truck can roll down a hill with you under it so make sure you block the wheels at least as you check it out!
Check your Tcase shifter for binding or misalignment before you dig into things any farther.

One other thing. Didn't just pull the front shaft out of it for some reason, did ya???

The np203 has a differential inside as its a "full time" transfercase.
Unless you lock the transfer case into "4 lock" you may get the same issues you describe, as the internal diff will send all power to the driveshaft with the least resistance. Take out the shaft and it has ZERO resistance!
The diff does its job and you go nowhere.

Kits to convert the np203 into a regular Tcase (along with front axle locking hubs) used special inserts to replace the diff gears, thus locking them solid and allowing the case to be used in a 2 wheel drive mode.

Be careful and don't get yourself hurt!!!

 

an '85 K20 really?

 

That's what I was thinking.

 

Take it to a ****** shop

 

Yeahhhh....I saw that too.
Who knows, maybe he tows Deuces home with it or something!
No rule that says you only have one vehicle.
He might have a full fleet of "on topic" rides, but either way, no harm to give the guy a bit of help if we can...dead ******'s ****!

 

If it's an 85 K20, the transfer case will be an aluminum housing NP208. This is true with the military spec CUCV/M1008.
Can't remember why I know that extremely well.
But, if it's a CUCV/M1008, it will have a Turbo 400.
Gotcha zman and Hackerbilt. Maybe the word is getting around that some folks around here know something.
Hmmmmm, traditional rod K20. Sumpthn ain't sound'n right.

 

It's a highboy in disguise

 

He says he transplanted in the T350 from a mid 70's truck.
I'm not 100% sure and I'm not gonna bother to look it up cause I'm freakin' beat (LoL), but I THINK the T350 and T400 of that era had different output splines so you would need a specific T case to match the trans?
Perhaps thats how the NP203 came to be in his pickup?
I dunno...by 1985 the splines might have all been the same across the board...but I vaguely remember something about spline counts in the 70's Chevy 4x4s.

 

To touch on a few of your points;
The truck originally had a 4-speed manual and a np 208 TC, the previous owner swapped in the TH 350 and the attached np 203.
The np 203 has a part time kit installed.
Both drive shafts are in.
Last night i tried moving it forward with the transmission in park and it rolled freely. Even after shifting the TC into all positions, it still rolls. So it must be either stuck in neutral or something has snapped inside. Either way i suspect the ****** is not to blame. Oh, and by the way, is there something wrong with calling the truck a K20? I always ***umed the K denoted 4 wheel drive and the 20 denoted 3/4 ton, no? Anyway, thanks for the advice.

 

Closed thread...this forum is for traditional hotrods and customs..if you want to know about 80s 4X4 pickups, go to a forum that deals in those kinds of vehicles..we don't.