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Old 07-29-2012, 03:29 PM   #1
teamssc
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78 NP203 oil change question

I've only had this truck a few months and it runs great. I'm trying to work my way through the fluid changes and want to change the fluid in the NP203 but I can't find have gaskets to put the covers back on. Where can I find the two gaskets I need? I've found whole rebuild kits for $25 or so, which I don't mind spending, but I only need the 2 gaskets. I guess I can always drain the fluid now and do the gaskets later. With 5 qts of 10w30 just running $15 it's no big deal to do it now and later.
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Old 07-29-2012, 04:38 PM   #2
Lobie
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Re: 78 NP203 oil change question

Try here
http://www.drivetrain.com/parts_cata...e_Illustration
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Old 07-29-2012, 04:55 PM   #3
teamssc
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Re: 78 NP203 oil change question

Quote:
Originally Posted by Lobie View Post
Thanks, I've looked at those diagrams before and I'm not seeing the external cover gaskets. Actually I'm not seeing the covers in those diagrams at all.
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Old 07-29-2012, 05:17 PM   #4
teamssc
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Re: 78 NP203 oil change question

The rear cover you take off might be called a Housing to Chain Cover Gasket. Not sure

NP 203, Housing to Chain Cover Gasket, Code: 301306
Industry Ref # D4TZ-7086C
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Old 07-29-2012, 05:37 PM   #5
teamssc
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Re: 78 NP203 oil change question

Here's the 301306 gasket. Doesn't look the right shape. http://cobratransmission.com/index.p...ts_id=55013025

Here's a link to a picture of my transfer case. What I need is the gasket to the right. There is also a rectangular gasket on the left side lower that can't bee seen in this picture. (also if someone determines this is not an NP203 please tell me.)

http://i926.photobucket.com/albums/a...ansfercase.jpg
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Old 08-01-2012, 04:44 AM   #6
teamssc
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Re: 78 NP203 oil change question

Bueller?... Bueller?... Bueller?

This still isn't resolved. Is there anyone who can offer some more help?
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Old 08-01-2012, 09:33 PM   #7
bilfman
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Re: 78 NP203 oil change question

Just clean off the surfaces well with a wire brush, wipe clean with some brake cleaner and seal up with a healthy bead of silicone. I like permatex ultra grey.

Smart move on the 10-30 lotsa peeps put in gear oil in the 203 and burn em up. I prefer plain 30 over the 10-30.

Also a great tip if you have converted the 203 to a part time. There is oiling issues because the 203 is designed to be spun fulltime. So if converted to part time engaging it every 100 miles or so was the answer. I had an ol guy at a tranny shop tell me a tip that eliminates the need to engage the t case or hubs. Just get a 1/2" 90 elbow, a 1/2" 2" nipple and a cap. Extend the fill hole 2 inches higher with the elbow and nipple and then cap after you fill the case. Basically this just fills the case with about another 2 1/2" of oil and it keeps everything lubed without having to engage the case. I did this on mine and never had an issue.
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Old 08-01-2012, 11:59 PM   #8
teamssc
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Re: 78 NP203 oil change question

Bifman, that's exactly what i needed to hear, using the permetex and the nipple idea. Since my 203 has been converted the extra oil will surley extend it's life. I'd heard about the nipple before and forgot it. It will be good to get inside the case and check it out. I might need a chain so this way I'll have some piece of mind.

Many thanks!
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