Tech question K10

[beanious]

Hello all, I have a 1971 K10 shortbed with a SBC 350, TH350 and a NP205. All new. I have less than 5,000 on the entire drivetrain since all three have been replaced or rebuilt. It's lifted 6" suspension and 2" body, as a result I installed custom length driveshafts from Tom Woods (really nice pieces btw). My question to all is what everyone thinks 4WD speeds should be limited to. Obviously it should only be in 4WD on dirt or snow and I should be careful because 4WD doesn't mean 4wStop. I would just like a firm MPH to ensure nothing gets damaged as I travel over Donner Summit CA in the winter months. Thanks for your help!

[beanious]

Anyone?

[k29349]

As long as your front drive shaft is not binding at full axle droop, you should be able to go as fast as you feel comfortable with.

[Bigdav160]

I think the driving conditions would be a bigger factor than the extra axle and driveshaft.

[Grumpy old man]

With 8"s of total lift , oversize tires ? , driving in steep snow covered roads ? and the trucks center of gravity so high and a short bed wheel base with the slowed suspension response I wouldn't push it over 40 mph . Guard rails don't care if it's 4wd they still bite .I wouldn't want to be the guy coming the other way seeing you running 60 in my lane on a corner on a snow covered road . Conditions determine SAFE speed NOT EQUIPMENT .

[beanious]

Hello all, I would like to update this subject with some info. Last summer I changed out the rear leaf springs and as a result I adjusted my rear driveshaft length. I pulled the rear driveshaft and ran it in in 4wd hi for a week in order to get to work while the shaft length was being fixed. My daily drive was roads and highway but no freeway.

The results were interesting, it drove perfect under 45 mph. After that it had a light vibration, I'm assuming that was either driveline or axleshaft. To be safe I tried to keep it under 35 most of the time. Another quirky side effect is that I would burnout in the front if at a stop and gunned it while turning. Probably the camber of the front and that I have a Limited Slip in the back.

I like to eliminate problems just for fun, so if anyone has any good suggestions on how to eliminate the vibration please let me know. Thanks in advance.

[fatbass]

That light vibration at 45 will go away at 70.

[jeffahart]

The puny cabs on these trucks are so light there is no top to really make the center of gravity a huge issue, unless you got a camper. All things equal of course, an HD lift with 35s can hug the road pretty damn good. I would rather a good 4" HD and proper shocks and tires be on the road than some of the stock setups I see. And some of todays "Sofa" suspensions are a different story of course, and with a short wheel base if you don't endo or loop it from the bucking bronco effect.. then I agree.. your over the guard rail. But again, you will probably hop over the rail from the oscillating and bucking.

[Alex V.]

As others have said, all driveline components being in proper order the driving conditions should limit your 4x4 speed before the driveline itself will. I've run countless trucks in 4WD at 50-60 on dry pavement, on basically straight roads for a few miles at a time.