Help ID 1986 K3500 Transmission and TCase

[Gunny65]

I have a 1986 GMC K3500 and I can't figure out what transmission and Transfer case it has in it. It came from the factory with a 7.4L 454 engine.

The Tcase looks like an NP205. It has the 2 to 2-1/2 inch 3 bolt panel right in the middle of the back of the case. I can't find any markings at all on it. The shift pattern is (top to bottom) 4LOW-N-2HI-4HI.

It has an automatic trans. The trans has a tag but it is unreadable. Its to corroded.

I would provide pics but my wife has the camera and won't be back till late tonight. Is this enough information to get a good idea?

 

[onetonbb74]

th400 and np 205. Pretty common for that year...

 

[76zimmer]

ditto, round pattern 205

 

[wasted wages]

Square pan on the trans = T 350 (doubtful behind a big block.. )

Texas shaped pan = T 400 ( well,,,kinda shaped like texas... )

 

[Gunny65]

Okay, thanks. I thought the Tcase was an NP205 but wasn't sure. From the reading it looked like the TH400 was a pretty good contender but the 4L80E also seemed possible. I just don't know how to tell the difference visually. EDIT: It has the odd shaped pan...see below.

Now for the followup question.

I have a 700r4 and NP241 in my K5. I had planned on keeping those in the K5 but that was before I decided to use the DRW axles off the K3500. I am transfering the front K3500 D60 and rear D70 axles over to the K5. I will also be rebuilding the 454 and using it in the K5. Should I transfer the trans-TH400 and Tcase-NP205 from the K3500 to the K5 or just keep the 700r4 and NP241 in it.

The pan has the unusal shaped pan. The "Texas" shape. LOL

 

[nvrenuf]

Fyi, the 4l80e was not available until '91.

I'm a hardcore 400/205 fan but the 700/241 isn't a bad combo. The o/d would allow you to take advantage of the very deep ratio options offered with the Dana axles as well as the 241 having a lower low range than the 205. That said, if brute strength is the goal, the 400/205 is the way to go.

 

[thatK30guy]

Okay, thanks. I thought the Tcase was an NP205 but wasn't sure. From the reading it looked like the TH400 was a pretty good contender but the 4L80E also seemed possible. I just don't know how to tell the difference visually. EDIT: It has the odd shaped pan...see below.

Now for the followup question.

I have a 700r4 and NP241 in my K5. I had planned on keeping those in the K5 but that was before I decided to use the DRW axles off the K3500. I am transfering the front K3500 D60 and rear D70 axles over to the K5. I will also be rebuilding the 454 and using it in the K5. Should I transfer the trans-TH400 and Tcase-NP205 from the K3500 to the K5 or just keep the 700r4 and NP241 in it.

The pan has the unusal shaped pan. The "Texas" shape. LOL

Whats the intended plan of use for the K5?

Is the K30/3500 a nice truck or a beater?

 

[Gunny65]

Whats the intended plan of use for the K5?

Is the K30/3500 a nice truck or a beater?

The intended us for the K5 is wheeling. Be it mud or trails. No serious rocks at this point. It is not a DD by any means. It is my toy.

The K30 is not quite a beater but it is not in great shape either. I would say it closer to a beater though. I have someone who wants the chassis after I take the engine, axles, trans, & Tcase out. I gave it to him for $350 and he pulls it away.

Thanks for the 4l80e info. It helps confirm that I have the TH400. I will keep the 400 and 205 for later use. Rock crawler with doubler, who knows. I don't know much about it so that will come with time.