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post #1 of (permalink) Old 04-12-2003, 06:13 PM
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What weight oil for NP435?

Hi guys, I have a Ford 5.0 bolted to a Ford NP435 tranny. What weight tranny oil should I be using? I'm using SAE 50 right now, but the rear lower cover of the NP435 is leaking a bit, and I noticed that once the tranny gets nice and warmed up the oil seems a bit thin...I don't want to damage anything!

Also, the tranny makes noise as it gets up to speed, and I'm wondering if that is a side effect of too thin oil? It makes a sort of loud hum and it gets louder the faster you go. Doesn't go away until you competely stop and it makes the noise regardless of the clutch being in, shifter in neutral, etc. Anybody else have an NP435 that is a bit noisy...maybe it's normal? Thanks for any advice!

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post #2 of (permalink) Old 04-12-2003, 07:11 PM
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Re: What weight oil for NP435?

The 435 should have regular 80-90w "gear lube" in it. (thats what my kick a$$ tranny shop tells me that it calls for) I would think 50 would be too thin.
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post #3 of (permalink) Old 04-13-2003, 05:06 AM
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Re: What weight oil for NP435?

I'll second that 50 seems too thin. Go with Dirt's selection.
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post #4 of (permalink) Old 04-13-2003, 08:18 AM
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Re: What weight oil for NP435?

My factory Ford manual calls for 50 weight. I just bought 4 quarts last night. Last time I filled it ,I went with a mix of 1/2 50 and 1/2 80-90. Might do it again. I think they shift better with 50wt. [img]images/graemlins/confused.gif[/img]
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post #5 of (permalink) Old 04-13-2003, 11:23 AM
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Re: What weight oil for NP435?

I run 80W90 in mine ,no problem with shifting ...but I put all new Synchro's in when I had it apart...only gear on mine that is noisy is first ...but being in the flatlands I hardly ever use it anyhow.
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post #6 of (permalink) Old 04-13-2003, 03:57 PM
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Re: What weight oil for NP435?

Well Dirt Dog, I am really starting to like your tranny guy [img]images/graemlins/grin.gif[/img]

I drained the 50 weight today. It came out a bit foamy...I don't think that is good, but what do I know. This thing literally has like 5 miles on it...should it be foamy already?

Anyways, I filled the hoss up with 80W 90 gear oil and I noticed my Dana 300 was about 1/2 quart low too, so I topped her off, and the noise is gone! Granted it still makes *some* noise and the Ford 5.0 is a bit obnoxious as well, but the noise I was originally refering to is now a distant memory. Thanks for all the replies guys!


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