68 GMC 4x4 chassis being built to be a 70 4x4!

[Patsfan34]

Well, I'm getting close to having the frame blasted now. Just need to pull t-case, tranny and 292 (which is for sale on the parts forum) and then the real fun begins. Here's a couple pics so I can remember what it looked like as a GMC. From what I've been told the Rockwell T-case is pretty strong, but I don't need to upgrade to the NP205 cause I won't ever be towing or plowing with this truck. I doubt I'll even need to put it in 4WD low! The tranny I think has a granny gear so I may need to get a new tranny for this build cause this truck will be my winter daily driver. I'm swapping out the 292 for a 350 4 bolt with 59K original miles. Let me know what you think and thanks for looking!

[292farmer]

nice start, the transmission looks to be a sm465 gear ratios are 1st 6.55:1
2nd 3.57:1 3rd 1.57:1 4th 1:1 reverse 6.05:1 i also sent u pm

[Patsfan34]

Originally Posted by 292farmer

nice start, the transmission looks to be a sm465 gear ratios are 1st 6.55:1
2nd 3.57:1 3rd 1.57:1 4th 1:1 reverse 6.05:1 i also sent u pm

I was told that my tranny is a sm420, due to the fact that this specific tranny has the plug directly on the top of the tranny for the reverse lights. But please tell me if that is incorrect cause the more I know the better off I am. And I sent you a PM back, that 292 is for sale on the parts board.

[292farmer]

both sm420 and 465 has plug on top at least my 465does i loaded a pic of a sm420 and a sm 465 first pick is sm420 the second sm465 the 465 has those large ribs in the side of the case as yours does and the plug for yours is in same location as the plug in pic of 465 drivers side top in front shifter

[Patsfan34]

292farmer, I just went out to my garage to take a closer look and YOU ARE CORRECT. Thanks for looking out!

[BurnoutNova]

I belive the shift pattern will also identify which you have. My 67 had the SM420 and reverse was to the left and down. My 69 K20 and 68 K10 were to the right and down. I was also told that '67 is the only year they used SM420's in out trucks.

[Patsfan34]

Yup, that sounds about right too!

[brianthelion02]

Unless you just want to stay original,i would be on the lookout for a replaement for the rockwell t-case!I know they are bulletproof which is somewhat their downfall.They have straight cut gears in them which makes them fairly noisy! If you are building a cruiser you probably wont like tha much! My 69 k-20's rockwell drove me nuts!Dang thing sounded like a jet airplane takin off at 30 mph plus!!LOL

[Patsfan34]

Originally Posted by brianthelion02

Unless you just want to stay original,i would be on the lookout for a replaement for the rockwell t-case!I know they are bulletproof which is somewhat their downfall.They have straight cut gears in them which makes them fairly noisy! If you are building a cruiser you probably wont like tha much! My 69 k-20's rockwell drove me nuts!Dang thing sounded like a jet airplane takin off at 30 mph plus!!LOL

Well, I really didn't want to spend any money on another T-case. I was going to have this one inspection, and if no problems was going to throw right back in. What are rebuilt NP205s going for these days? And yes I'm just building a cruiser!

[brianthelion02]

Since you have it i would go ahead and run it,but if you see somethin else within grasp,id grab it,lol!! I pulled my sm-465 and put in a 700r4 with a np241 behind it!Love the 3 mpg it gained me and the ability to cruise at 75 mph with no problems!Also nice and quiet!You might ask around those who are running the rockwell!I thought somethin was wrong with mine but was told by several people that was a side affect of having the super strong straight cut gears!

[wancosc356]

So thats what it looked like yesterday. I assume you already got it disassembled and its at the blasters now...right! haha. Just messing with ya man. Can't wait to see this one come together.

[Patsfan34]

Originally Posted by wancosc356

So thats what it looked like yesterday. I assume you already got it disassembled and its at the blasters now...right! haha. Just messing with ya man. Can't wait to see this one come together.

The funny thing is the more I get into this build the more I keep changing my mind on things. But I still can't wait to be finished!

[wancosc356]

Originally Posted by Patsfan34

The funny thing is the more I get into this build the more I keep changing my mind on things. But I still can't wait to be finished!

That's how it goes. I keep adding and subtracting from my build plans every day. And I haven't even started. Haha.

[msgross]

If you are going to use it as a daily driver, and want a manual shift tranny then I suggest an NV4500 woth an NP205 adapted to it.

Rockwell and 205 are both gear driver, rockwell is noisy and parts aren't cheap... 205 parts are cheap and very common...

the NV4500 is a five speed tranny which will make for a nicer driver.

check out Rust Buster and Musclerodz build threads for this setup...

I'm gonna move this over to the 4x4 builds...

[mstrav1973]

you will find as I have / did, that the design and intent of your build will evolve as you progress. I had so many things set in stone, and then later go a total dif route after getting more ideas.

I am showing you a pic of my frame last november when I started to help inspire you.


Matt

[mstrav1973]

heres this last october

Matt

[Patsfan34]

msgross, I'm thinking that I will probably go with that drive train setup. Now I'll just need to find that stuff or hope someone will do a trade.

mstrav, nice work man. Those pics give me something to look forward too!

[litebulblsc]

Does anyone else thing that the tcase looks like a 205?

[Patsfan34]

Originally Posted by litebulblsc

Does anyone else thing that the tcase looks like a 205?

That I'm positive about. Its a rockwell, you can tell by the linkage and also it still has the name plate right on top of the T-case.

[Patsfan34]

Donor body, well sort of. I just sold the bed today to shortbedbob, but I'm using the cab and some of the front clip and definitely the engine.

[Conroe trucker]

You might sriously consider keeping the 292.

They run forever, and are cheap to rebuild.
The amount of torque you get at low RPM is matched only by a big block.

And, you are not like everyone else.

Problems are low RPM make it a low speed car.
I top out around 55 MPH, but hey, it was never built to go fast was it?

Mike

[Yukon Jack]

Just keep an eye on the level of the Rockwell's gear oil and you will be fine. The are a bit louder than an NP205 but not loud enough to be a major issue IMO. An NP205 with the correct adapter to mate to your SM465 will run between $200 to $400, at least around Kansas.

[Patsfan34]

Originally Posted by Yukon Jack

Just keep an eye on the level of the Rockwell's gear oil and you will be fine. The are a bit louder than an NP205 but not loud enough to be a major issue IMO. An NP205 with the correct adapter to mate to your SM465 will run between $200 to $400, at least around Kansas.

I'm up in the air about switching. I think it will all depend on the condition of the rockwell when I break it open. If its in good shape and doesn't need an overhaul, I'll use it. If it's trashed I'll probably upgrade to the setup msgross suggested. Thanks for the look Jack!

[my67chevytruck]

subscribed... just picked up a 69 k10 roller and will need ideas/inspiration......

[vk_chevy]

this is a cool build,