Rockwell or NP205?

[1969k10stepside]

Ok,so I think I found a motor to go in the 69 K10 so Im thinking about the transfer case now.My cousin is junking his 78 K10 shortbed after he hit another truck head on and bent the frame.The truck has a 292/SM465/NP205.Now,the rockwell I never had any problems with,it functioned properly and didnt leak fluid.Do you think I would be better off swapping the 465/205 in?I have the 465/Rockwell out now so sooner or later one combo is going to have to go in.Should I wait for something to go wrong with the Rockwell first before swapping (nothing may ever go wrong with it though)? Are the 205 and Rockwell about the same durability wise? Is there an advantage to using a 205 over the old Rockwell? I'v only heard good things about the 205 and the Rockwells,I'v heard of them blowing up and not so good of things with them although I never had any problems with mine before I pulled the drivetrain out.As for changing other stuff,I'd have to use a longer 205 driveshaft for the front (longer than one with a Rockwell).Would I also have to change to a 1 piece rear driveshaft?With the rockwell it isnt one piece and the trucks with 205s had one piece driveshafts.

[Yukon Jack]

I would just keep the Rockwell in there and have the NP205 as a backup should something ever happen to your Rockwell. I can't see you having a problem with your Rockwell unless you run it low on gear oil. They are just as tough as the NP205, have the same gear ratio and of course both are gear driven. I do know the Rockwell in my 69 is alot louder than the NP205 in my 70 but that doesn't matter to me. I don't have any thoughts on your driveshaft questions.

[1969k10stepside]

That's what I was thinking,have it as a spare and bolt it in if something would happen to the rockwell.The whole truck is going to be junked,I think he is keeping the motor though.He dont have any more GM 4wds so he doesnt have a truck to use to the tranny/t case in so I might as well get them.Never know when you could use an extra t-case/tranny.Like I said,no issues with the rockwell.I dont feel like moving the t-case crossmember back and switching to a one piece rear driveshaft (If I would have too).I just have to find everything to bolt the truck back together and I'll be in good shape The parts are scattered everywhere...

[scotto0609]

Remember, if its free take everything you can!

[msgross]

When you say one piece drive shaft are you referring to a non-carrier bearing or a solid fixed drive shaft with no slip joint? My SWB with rockwell has one driveshaft with no carrier bearing...

[1969k10stepside]

I mean without a carrier bearing...The lwb with rockwells had a carrier bearing on the driveshaft.The swb,dont think so.When GM switched to the 205 they eliminated them swb and lwb (so,I have heard..).Maybe its because the 205 sits back farther than the rockwell? Dont know...

[DieselEater]

The 205 is WAY STRONGER than the rockwell!!!

But, if your not doing anything in a pull/crawling application with low gears and high power, then you probably don't need the extra strength anyway. Definitely take it for the future though.....

Not one puller I know would use the rockwell....

[1969 GMC]

Personally, I would swap it out now while it's easier to get to.

Have you checked the splines on the sleeve? They might be worn, which is an issue with both cases. I had thought about rebuilding my Rockwell since none of the gears were damaged that I can see, but the output of the tranny was wrecked and so was the sleeve in between.

[1969k10stepside]

Havent checked the splines yet...As for the truck's use.Gonna build another small block somewhere around 350 horsepower for it.Just a truck to use on the trails and in the mud.6" lift and 35" TSLs.SRW 1 ton 14 Bolt rear and Dana 44 front.

[JAKES 68GMC]

My truck had a rockwell and had/has a 1 piece driveshaft. I'd probably swap it while it's easy to get to Dustin, like said above. That way you can smile while blasting through a mudhole, instead of looking down at a whining transmission hump with a worried look on your face.

Moving the crossmember back isn't that big of a deal. If I can do it, than its not that hard.

[msgross]

mine has lasted 40 years, longer than I have been around. I would pick up the extra and then decide....whatever makes you happy is the way to go...

[earl87gta]

I went to a 205 from the rock just becuse every time my wife was in the truck the noise from the rock made her feel like the truck was coming apart.

[vectorit]

Very interesting thread, since I have a Rockwell transmission and TC.
The whine... while growing up in this truck as a kid, the whine was a constant topic of contention between my mom and dad. The whine was so damn loud, it litterally made my mom cry during long trips and we'd have to pull over.
I being older now, and the current owner of the old burb. I have had a trans guy go through both, and the tranny guy said that the input shaft of the trans was shot and it was replaced. He also replaced a gear (Can't remember which one now) that he said was a "failed experimental idea" that GM had in 68, being that there was embeded rubber material in the inner part of the gear that was supposed to quiet down the noise? He showed it to me where all the soft material rotted away, making the gears sloppy when assembled. He replaced it with another gear that didn't have that design, but to my disappointemnt the whine was still there... Oh well, I am use to it since I have lived with it for 30 plus years.
Has anyone ever heard of what this tranny guy was saying to me? The guy is a respected transmission specialist, so I felt comfortable about everything he was saying to me.
When I am done with everything, I have thoughts about upgrading to a newer more quieter system. But until then the old burb is gonna sound like an old yellow school bus going down the street.

[1969 GMC]

These trucks never had a Rockwell transmission, so if you have one it has been swapped in. The gear whine is from the transfer case itself, and it really isn't THAT loud. I just took it as another quirk of owning an older vehicle. I had no issue listening to my stereo over it at highway speeds, even with the windows down. Then KABLOOEY, there went the Rockwell.

I think the fault lies in how the truck was used....ridden hard and put away wet at a farm, and sat for long periods of time between uses...so when I started driving it regularly, the seals just keeled over and it started to leak. I know fingers are gonna point at me and say I drove it like an idiot, but contrary to popular belief, not all teen to early 20 males beat the piss out of everything they own.

It's also partially the design of the t-case itself, very tall so the input bearing (what went on mine) would starve if your oil gets low.

You could definitely still run it no problem if you rebuilt it (or at least resealed it) and kept your eye on the oil level.......or swap in a 205 and not really worry about it, the only thing that usually leaks on 205's is the shift rail seals (which is only a few drops at most) and the slip yoke (if equipped).

[1969k10stepside]

I dont remember mine making much noise..If it was I couldnt hear it over the tires and exhaust leak!
I think I'm gonna swap the 465/205 in...not that much of an issue...might be better off doing it now than pull it back in the shop and swap them out later on,or break on me out on the trails or on the side of the road..

[msgross]

if your skeered just say your skeered Dustin....

[1969k10stepside]

I'm much more worried about falling through the floor of the rust bucket than the t-case exploding!

[msgross]

I always hated mud splashing up on me in my old 79 blazer! Few pop rivets and I was set....

[eedgell]

Out with the old in with the new I always say. Np 205, no regrets!! Besides, why would you wait for it to break so that then you could fix it, when you have it all apart now. Fix it right, and forget it.