I haveing a poping in frontend.?.Under hard Acc.only.Like something is binding up.My u-joints look O.K.My truck is a old farm truck 1977 3/4 350/350trans 8lug has 4.56 gears no lift(yet)running 265/75R16 A/T tires.I think a np203 case?  

If you have a 203, (which you should) it could be the chain in the Tcase slipping for wear and stretch. It can cause it to bind and "pop" at times. Generally these chains last for life of vehicle if there are properly serviced regularly. They will suffer from neglect. that aside, 30 years is a long service life and it may be time for a overhaul. Chains are not very expensive and it is possible to change it with Tcase in truck. (it does take some work though)  

thanks. where to get inst./how to infore to this in truck fix how hard is this chain repair?is the 203 good or bad?  

THe 203 is not a bad case. The only thing "bad" about it is that it is fulltime 4x4 drive and that because of this it used a little extra fuel but for a farm truck, it is idea. It is a strong heavy unit. You are supposed to use straight 30 weight non detergent oil in it. (you can use straight 20 non detergent in winter) the reason you use non detergent oil is because it reduces tendency to foam and lubes Tcase and chain better. Any old Chilton's manual that covers trucks for 73 to 79 should have overhaul info in it and same Tcase was used in Dodge and Ford during those same years too. Below is a link for a overhaul kit on Ebay but I do not know if it includes a new chain. If not figure on about another 100 bucks for chain.

Click Here  

my hanes repair book said to run either 10-40 or 10-30 wheight oil in the 203, i recently filled it up with 10w40, *** case takes a lot of oil.  

Geo450racer:
my hanes repair book said to run either 10-40 or 10-30 wheight oil in the 203, i recently filled it up with 10w40, *** case takes a lot of oil.

The Hanes manual is wrong. The Tcase was spec'ed for low foaming non-detergent straight weight oil not 10w30 or 10w40. I was around and driving when the Tcase was new and remember it well.  

thanks for the info!going to by hanes.yes solid axles cant be beat! ??lt.gear-lube???maybe??/or ???  

Those cases where spec'ed for straight 30 non detergent. The many reason is better lubrication and less foaming. Detergent based oils can foam a lot at speed in a chain driven Tcase and compromise lubrication. I have a old original Jeep Qtrac fulltime 4x4 from 70's still and it was spec'ed for 20W non detergent with a additive.  Mine has held up well and chain was still in tolerance when I last checked it a few years ago. It has had its fluid changed maybe 4 or 5 times in its 28 year life and 110k miles.  

o.k. 4x4 is somewhat new to me sorry about all the ????'s.Trying to make dailey driver/weekend funner.lol.cant find books 73-78/83 for how toos.My truck is over 100k.newer 350 (30-40k)when I bought from gramps.So any other todo or dont's?  

junk77:
o.k. 4x4 is somewhat new to me sorry about all the ????'s.Trying to make dailey driver/weekend funner.lol.cant find books 73-78/83 for how toos.My truck is over 100k.newer 350 (30-40k)when I bought from gramps.So any other todo or dont's?

Check out link below, it is just what you need.

Click Here  

thanks!how hard is it to double up?203/205,???or whats the better single Tcase to run?To upgrade to with all-time 4X4? Don't want to conv. to lockout hubs.  

junk77:
thanks!how hard is it to double up?203/205,???or whats the better single Tcase to run?To upgrade to with all-time 4X4? Don't want to conv. to lockout hubs.

You already have all time or full time 4x4 drive, a 205 is part time 4x4. The doubling you are talking about is the you use the planetary reduction off of a 203 and adapt it on a 205 input and that give you a 3 speed Tcase with 1 to 1, 2 to 1 and 4 to 1 reduction ratios.