k35 from Fresno, greetings all

[Bextreme04]

That's what all the th400 1-tons got, '77-'79.

After some research I see that they didn't allow the 205 to pair to a TH400 until '79. Super weird. So if you had a TH350 or SM465 from 71-79 in a 1-ton, you could have the 205, but not if you had the TH400. Seems odd to only allow the strongest transfer case to be behind the weaker trans, but it is what it is.

 

[bucket]

After some research I see that they didn't allow the 205 to pair to a TH400 until '79. Super weird. So if you had a TH350 or SM465 from 71-79 in a 1-ton, you could have the 205, but not if you had the TH400. Seems odd to only allow the strongest transfer case to be behind the weaker trans, but it is what it is.

I don't believe strength had anything to do with the reasoning. '77-'79 K30's with th400 got the full time 203, keeping in line with the lighter duty trucks with automatic that came standard with the full time 203. Manual trucks got part time 4x4, auto trucks got full time 4x4, across the lineup.

 

[Jwedd]

I've read different things here and there about the strength of the 203 vs the 205. Is there a better transfer case for this combination (th400 77-79) that will bolt up? I don't have a particular issue with the 203 yet. I had a guy show me how to properly shift it from high to low without grinding. The dash still has "direction" labels stuck to it from the fire service on how to "shift", all requiring complete shut down of rotating parts. I got locked into 4h loc one time on pavement, that was no fun.

Mainly what I would like to see is over 10mpg, but I suspect I'll never see 15. I thought about converting to the Mile Marker part time, but it seems that the mpg benefit isn't much, and some risk of poor lubrication.

 

[bucket]

I've read different things here and there about the strength of the 203 vs the 205. Is there a better transfer case for this combination (th400 77-79) that will bolt up? I don't have a particular issue with the 203 yet. I had a guy show me how to properly shift it from high to low without grinding. The dash still has "direction" labels stuck to it from the fire service on how to "shift", all requiring complete shut down of rotating parts. I got locked into 4h loc one time on pavement, that was no fun.

Mainly what I would like to see is over 10mpg, but I suspect I'll never see 15. I thought about converting to the Mile Marker part time, but it seems that the mpg benefit isn't much, and some risk of poor lubrication.

10mpg should be perfectly possible as it is. Much more than that, you are throwing a lot of $ at it that will likely never be recovered with fuel savings.

To swap a 205 in place of the 203, you are basically looking at a trans rebuild because the output shaft would need replaced.