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well, fixed one leak but have another. Got the case drained and re-sealed and added 30w oil. Pretty sure what I drained out was gear oil judging by the smell. However, guessing maybe the thinner oil I am using now is causing the seal around the rear drive shaft output to leak . This a.m. i had a nice little puddle under the TC
How involved is it to change this seal or seals (looking at diagram it appears to be several seals in this area)
The seals are easy to change... but try not to tear them up. There are two different sized output shafts and the smaller of the two, the seals are not listed anywhere. You'll have to measure them to find a replacement. I have posted a ton of information on this site about NP203s since I just went through rebuilding one (read: sourcing parts) and although I am really happy about it, it's not for the faint of heart. Ha! Those docs that 77&79F250 posted are from my truck. pretty neat to have all that old original paperwork.
If you search my name and NP203 you can find the seal sizes and comparisons. It's one of the few things i have ever seen stump the NumberDummy.
Anyhow, if you have any questions, I can probably help answer them as it's fresh on my mind at the moment. There are also two different size chains internally. Mine was slipping, one size chain was available (NOS) and the other was not. No one mass produces a chain any more. So.... we had to swap the chain AND sprockets to the stronger smaller chain. They are a bit of a rarity anymore for all those reasons, but I like em, dont put a ton of miles on my truck and had the patience and money to make mine right again. I could have easily swapped to a 205 for the money I put into rebuilding mine. ha!
The seals are easy to change... but try not to tear them up. There are two different sized output shafts and the smaller of the two, the seals are not listed anywhere. You'll have to measure them to find a replacement. I have posted a ton of information on this site about NP203s since I just went through rebuilding one (read: sourcing parts) and although I am really happy about it, it's not for the faint of heart. Ha! Those docs that 77&79F250 posted are from my truck. pretty neat to have all that old original paperwork.
If you search my name and NP203 you can find the seal sizes and comparisons. It's one of the few things i have ever seen stump the NumberDummy.
Anyhow, if you have any questions, I can probably help answer them as it's fresh on my mind at the moment. There are also two different size chains internally. Mine was slipping, one size chain was available (NOS) and the other was not. No one mass produces a chain any more. So.... we had to swap the chain AND sprockets to the stronger smaller chain. They are a bit of a rarity anymore for all those reasons, but I like em, dont put a ton of miles on my truck and had the patience and money to make mine right again. I could have easily swapped to a 205 for the money I put into rebuilding mine. ha!
thanks!! Been reading through your post and trying to get part # together.
Do I pretty much have to pull the seals out to figure out what size I am going to need? Any trick on getting seals out/back in ?
looks like I need 2 seals and the rubber spline washer, correct?
There is a input seal and rear and front output seals. The spline washer are tough to find. Measure the shaft of your front output shaft. If it's 7/8" the parts numbers in the book and the spline washers are easy to come by. If it's 3/4, you'll have to use the parts numbers i posted. I think that later cases used the larger output shaft, but I can't be sure of that.
There is a input seal and rear and front output seals. The spline washer are tough to find. Measure the shaft of your front output shaft. If it's 7/8" the parts numbers in the book and the spline washers are easy to come by. If it's 3/4, you'll have to use the parts numbers i posted. I think that later cases used the larger output shaft, but I can't be sure of that.
so it sounds like i need to take apart before i order seals, correct? Is there a quick write up on the process for this seal replacement?
