Manual Hub Questions.

[chargedstang89]

I have an '85 GMC 1/2 ton 4x4. The guy I bought it from said it has a 208 or maybe it was 205??? transfer case in it, which is supposedly a gear driven transfer case, not chain driven. Anyways, I was thinking about getting some manual hubs to help free up my front end and hopefully give me better gas mileage and acceleration. I have a couple of questions about this, though:

1. What hubs should I get and from where, as I have heard that my truck is a "full-time" 4x4.

2. During the winter, can I just lock my hubs in place and drive around with them like that so that if I need 4x4, I can just pull the 4x4 shifter inside to lock the transfer case in gear? I figure this would be the same as my hubs being locked in now, or am I wrong?

Any input would be great! JP

[BigAlVB]

I switched my 91 Suburban to Warn stainless manual locking hubs that I got from Summit. Yes, I had heard that the auto hubs were prone to breaking and were less fuel efficient. I usually lock my hubs in when needed and then turn them to "free" when I'm done. I have left them in lock during the winter because I forgot about them but I don't really know if it hurts anything or not. As far as fuel efficiency, I drive a 3 ton Sub (about a s aerodynamic as a brick) with a small block so I'm really not too worried about that, anyways!
Hopefully someone else more knowledgeable will post so I can learn, too!

[twxsby]

I did just that a few days ago. I have an 84 K-20. Replaced auto hubs w/ man warn hubs. I went with the heavier duty ones. I go to the mountains often and just leave them locked while up there. I have done the same thing for years with my ranger (warn man hubs), and never a problem.

[chargedstang89]

any word on gas mileage or acceleration advantages? my auto hubs work just fine. i just didn't know if this would help gas/acceleration

[mike reeh]

if your truck has automatic hubs, its not full time 4x4.. Gas mileage should not change.. the hubs unlock the front driveshaft & axleshafts just like manuals, only they do it automatically.. They are known for their unreliability though. I personally would swap them out.

Keeping the hubs locked is not a problem at all. The only thing it does is keep the front axles & front driveshaft spinning all the time, so it will create some parasitic drag on the engine (slightly worse mileage) and will cause "unnecessary wear" on front end components like u-joints, bearings, axle-joints, ring & pinion, etc. Which is really not an issue because there are a million full time 4wd trucks out there that are built exactly the same. Its kinda like worrying about "wearing out" your rear axle because you drive the truck.

chargedstank: regarding question #2, yes you can lock em in for easiness during the winter.. you'll still be in 2wd until you lock in the transfer case.

as for your transfer case its undoubtedly a np208.. the 205 is a part time case used in years previous to your truck. Yours should be the aluminum np208.. does the shifter have a Z pattern to shift into low range? If you look at the transfer case there will be a tag riveted or screwed to the main body with the model number on it..


hope this helps some

mike

[apstguy]

There is a problem with leaving it locked. Since there is no center differential on the truck, when 4wd is engagued, the front and back axle are locked into turning at the same speed. When you turn a corner on dry pavement, the front & rear axles NEED to go different speeds. This can cause vibration, major tire wear, and can damage the front drivetrain components. Or were you taking about just the hubs locked and not the transfer case?