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Thick or Thin ? Transfer case oil

jerrybromley

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Sep 17, 2018
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340
My "J" transfer case is giving me shifting fits ; )... I know these gear boxes are notorious for this. The shifter does not seem to push the shifting forks hard enough to engage the gears. When I pull the inspection cover and " nudge" the shifting forks with a screwdriver they seem go into place with little effort. I even changed out the shifter with very little improvement. I have been using 80w-90w gear oil. Will the 50w that Ford recommends allow the transfer case to shift better? Perhaps the James Duff " new and improved " shifter is the answer. Or is the gear box just so worn it needs a rebuild ? What do you guys think?
 
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jerrybromley

jerrybromley

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Sep 17, 2018
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Thanks Okie....I see you have twin sticks in one of your rigs..............If I have to drop the tranny and transfer case I may go that way
 

Rustytruck

Bronco Guru
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Feb 24, 2002
Messages
10,859
I use synthetic oil amsoil 90 weight which has the same weight as 50 weight motor oil.
 

Rustytruck

Bronco Guru
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Feb 24, 2002
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10,859
its a lot more slippery. all of my shifting issue went away by using a duff single shift shifter.
 
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jerrybromley

jerrybromley

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Thanks Rusty...I was hoping to hear of somebody having some luck improving a shift problem like mine without having to dop tranny and transfer case
 

SteveL

Huge chevy guy
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Jun 24, 2001
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11,251
If you have a j-shift it's probably worth going to a twin stick.
 
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jerrybromley

jerrybromley

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I have heard of multiple ways to relieve the torque bind that seems to be the source of difficult shifting of the transfer case. I have a c-4 , is putting the tranny in neutral enough to relieve the bind or is the rocking of the truck in gear required...Thanks for all the good answers to dumb questions : )
 

Glass Pony

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Feb 13, 2012
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Sussex County Delaware
I have heard of multiple ways to relieve the torque bind that seems to be the source of difficult shifting of the transfer case. I have a c-4 , is putting the tranny in neutral enough to relieve the bind or is the rocking of the truck in gear required...Thanks for all the good answers to dumb questions : )
I have a C-4 also. When I come off the sand I shift to reverse, blip the throttle and back up 5-10 feet, shift to neutral, and then the transfer case shifts very easy.
Works every time.
 

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,764
Loc.
Ridgefield WA
Jerry, I prefer to use the recommended SAE 50 motor oil. Some gear oils contain sulfur which will attack bronze parts. My '77 has way over 300K on it and the transfer case has never been apart. I'm way below the pay grade of an automotive oil engineer, and it's hard to argue with success.

Ours originally had a "J" shift, but changed to twin stick to install the NV3550 transmission. I was always happy with the "J" shift, but it takes some experience to get it to work properly.
First, never shift between 2WD and 4WD with the vehicle stopped. Always have it rolling, blip the throttle, then make the shift.
Shifting between Low and Hi, always stop the vehicle. Returning to Hi can sometimes be difficult because of gear bind and square cut gears.
In that case, rolling backward a bit should free it up.
 
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jerrybromley

jerrybromley

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Sep 17, 2018
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Thanks for the advice Blubuckaroo. This is the first J shift I have had and I am at the tail end of my build. I am trying to make everything as good as I can get it . From all the info that I have gathered the shifting of the transfer case just takes some getting used to
 
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