NP435 fluid
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Freshman User
Joined: Jul 2002
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From: midwest
NP435 fluid
OK, question, i just got done rebuilding an NP435 4spd. I went to autozone to buy some gear oil to refill the case. The guy said they don't carry it there and that it is a special dealer only item!! I personally think he is smoking crack. I misplaced my Haynes manual and i think it said something about 100 weight oil, but am not sure. What is some good fluid for my rebuilt beast?
Postmaster
Joined: Jul 2001
Posts: 4,038
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From: South Kitsap County, WA
NP435 fluid
Older units will have different requirements. I don't recall when multi-viscosity oils appeared, but the 50W may have been what was used years ago. I've heard of it used in NP205 cases. It's about the scientific approach of keeping the inserts and metals happy without having to worry about wear.
If you haven't rebuilt the older unit, it may not be a good idea to change over to a different oil weight. The inserts and other components may not respond well to the higher base weight and chemical properties (detergents). With a rebuilt unit I'd use a 75 and up base oil. I ran 80W-90 in my NP 435's ('73 & '82) without a problem, and had an aquaintance that ran 75W-140 in his.
-Kerry
If you haven't rebuilt the older unit, it may not be a good idea to change over to a different oil weight. The inserts and other components may not respond well to the higher base weight and chemical properties (detergents). With a rebuilt unit I'd use a 75 and up base oil. I ran 80W-90 in my NP 435's ('73 & '82) without a problem, and had an aquaintance that ran 75W-140 in his.
-Kerry
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Joined: Jun 1999
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NP435 fluid
The 72 manual recommends 50 wt also. Using the heavier weight in a mild climate area will probably not make a difference. If you live where it gets cold the shifting can be harder with the higher viscosity.
20 years ago I had a mustang 5 speed that I installed and ran gear lub in. It never shifted right until I found out it was supposed to use automatic trans fluid. It shift fine after that. I did blow it up shortly there after though.
20 years ago I had a mustang 5 speed that I installed and ran gear lub in. It never shifted right until I found out it was supposed to use automatic trans fluid. It shift fine after that. I did blow it up shortly there after though.
Post Fiend
Joined: Jun 2002
Posts: 13,873
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From: Atlanta GA
NP435 fluid
I have been running 85/140 in my 435, but, only have about 1000 miles on it so far and the weather is nice here. My biggest problem was getting the gear oil in! What I did was remove the tranmission cover, put a flexible funnel into the fill hole and fill it from above while I did other work on the truck. Took forever!
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