Full time 4x4 on 78 Chevy Truck

This truck has the NP203 transfer case. I know they make a kit to convert it but Id rather not do so.

It mould make a HUGE difference in gas mileage since the truck wouldn't move...

I installed a "Rough Country" part time conversion kit in my '76 Chevy Shortbox and mileage went from 12-15mpg. It was the first time I had tackled this type of job and it took about an hour to complete. I paid about 125 dollars for the kit when gas was pushing a buck a gallon. Rough Country no longer makes the kit, but here is a link to a similar kit for less money.

With gas prices at 2.50 - 3.00 a gallon it makes even more sense. Good Luck Regards, JR

On Fri, 14 Jul 2006 16:30:58 -0400, "Adam & Lisa" wrote:

I have been messing with 4x4's for about 35 years now and I remember when the 203 came out. I seriously question Petersons take on this. The 203 is a tuff case if maintained properly and removing the driveshaft will not kill it unless you have like 35's with a 3.42 or so because people tend to forget the strain that big rubber with tall gears causes to driveline. Some think a 4.10 is deep but with 35's it is not. If your truck is properly geared for it tires and you do not dog it and bet it with front drive frant removed, it will not suffer from it. ALso NEVER use multiweight oil in it as it was spec'ed for straight 30w non-detergent oil (detergent oil can foam badly in the case and inhibit proper lubiration. Some major 4x4 sites are really kinda brain dead about this too). I have a old 79 J20 Jeep with a BorgWarner quadratrac which is not as massive a tcase as the 203 and even drives both axles thru chain (203 only drives front axle through chain). I have driven it on a few 2000 mile (one way) cross counrty trips in the 90's with front drive shaft removed and tcase locked and it is no worse the wear for it and still runs today. The 203 weakness in lack of proper maintainance and proper lube. Do this and it is pretty sturdy. Back in about 1975 GM set a record by towing a 747 around a airport for a few hours with a stock K20 4x4 with a 203 and a 400 SB with 4.10 gears (it is in the book of world records) and at one time it even exceded the towing speed limit. This feat has not been matched to this day even by diesel pickups that always brag about their towing power. Chevy also did a comercail where the plowed a large feild with a multi bottom field plow mounted on a stock truck with a specail 3 point hitch. (same drive train as the one used for

747) One more thing, becarefull of some of those conversions because some are not strong nor do they properly lub critical bearing and thrust washers after conversion in 2wd. (the cheaper kits were the ones that did this mostly)

----------------- The SnoMan

Yeah, the truck wouldnt move till I put it in Hi-Loc with the front driveshaft out.

That's right...

But I read that when you remove the front shaft that will cause premature wear to the front bearings in the case.

So I wont be doing that.

You read wrong.

----------------- The SnoMan

So it wont hurt the xfer case if I take out the front shaft and put it into

4loc?

No, not as long as it is properly seiviced with the correct oil you will have no bearing problems. Not sure how that even started. I was around and driving when those things were new and been messing with

4x4's since about 1970 so I have seen a lot.

----------------- The SnoMan

All part time transfer cases should be run in 4wd for a mile or so every

5-10K as a precautionary measure to make sure that all the bearings are getting lube. An NP203 with a part time conversion should be run in Loc for a short distance about every 1000 miles since it was designed to have all components turning at all times when driving. With the front shaft out and a non converted 'case in Loc, it wouldn't be an issue.

You might engage 4x4 one a year od so to keep ujoints limbered up (it is more time than mileage releated). The problem with 203 part time conversions was that some of them were poorly designed and they did not properly lube some Tcase bearing in 2wd mode and hence the need to run them in 4x4 drive often. The better designed "kit" did not have this problem.. The 203 is a very strong Tcase and most that fail do so from neglect.

----------------- The SnoMan

Full time 4x4 on 78 Chevy Truck Group: alt.autos.4x4.chevy-trucks Date: Fri, Jul 14, 2006, 4:25pm From: snipped-for-privacy@verizon.net (Adam=A0&=A0Lisa) I was wondering would it make a difference in gas milage to unhook the front driveshaft? Since there is no way to shift this x-fer case into

2wd.

I bought a 1977 3/4 ton PU in 1980 that had the full-time 4wd. After I had to replace the front drive shaft because of a U-joint failure, I installed a Doug Nash conversion kit (one of the best ever made) and Warn manual hubs. I put 150,000 miles on that truck and never had a problem with the transfer case, tranny or axles in the 20 years that I drove it. I did, however, engage the 4wd at least once a month to keep everything lubricated. BTW Doug Nash is no longer in business.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% "Sometimes, when you're up to your butt in alligators, it's hard to remember that the intial objective was to drain the swamp." ~ Unknown ~

Hows come if these conversion kits are so good than why are all the manufacturers out of business? I think Id just rather leave out the shaft if anything till around late november than put it back in till february.

everything lubricated. BTW Doug Nash is no longer in business.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% "Sometimes, when you're up to your butt in alligators, it's hard to remember that the intial objective was to drain the swamp." ~ Unknown ~

The companies are out of business because there are very few people who used the products. Remember that in the 60s-80s a 4X4 was bought because they NEEDED 4X4 not as a yuppie desire. The folks who bought the kits were ones who wanted to drive the trucks longer distances and figured that they wouldn't need the 4X4 on the highway. Then in the late 80's the manufacturers more or less dropped the full time 4 wheel cases and the kits were now only needed by the people who were buying used trucks. The market just dried up. Doug Nash in particular is out of business because of the remnants of the company being bought up by another driveline company. That company no longer sells the conversion kits just the overdrive/underdrive auxiliary transmission that DN developed.

Rough Country is alive and well. They just don't make the conversion kit anymore. Remember, the newer transfer cases do not benefit from the conversion and you are talking about a 28 year old truck. Regards, JR