NP 205 won't go into low range - Off-Road Forums & Discussion Groups
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post #1 of (permalink) Old 11-19-2002, 08:11 AM Thread Starter
Way Outta Control
 
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NP 205 won\'t go into low range

I just recently bought a '72 Chevy 1/2T 350/auto/NP205 4x4.
D44 in front, 12 bolt rear.

Problem: It won't go into low range - is this likely a shifter
problem or more serious? The only 2 positions I can get it
in is 2Hi and 4Hi, not even neutral.

Also the 12 bolt rear end (12 bolts on the diff cover) -
is that a good one?

I don't like the ratios, 3.73's too tall for 35's.
What's the best way to go lower?

Thanks in advance, Rich
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post #2 of (permalink) Old 11-19-2002, 08:25 AM
**DONOTDELETE**
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Re: NP 205 won\'t go into low range

Might need to adjust the shifter linkage to the T-case. Does the truck have body lift or anything?
post #3 of (permalink) Old 11-19-2002, 08:47 AM
**DONOTDELETE**
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Re: NP 205 won\'t go into low range

Please correct me if I'm wrong, but I don't believe an auto/205 combo was origionally put in anything '72. So, it's likely it was swapped in. Pointing the cause of the problem to the shifter/linkage. The 205's linkage doesn't have any adjustments, or much else for that matter to go wrong. Check to make sure the lever isn't hitting the floor (or anything else), and that nothing is caught between the bottom of the shifter and xfer. 4lo and N are the forward most positions, which pushes the rails into the xfer the furthest. If the "s" shaped link between the shifter and the flat bar were bent or altered, perhaps the shifter doesn't have enough throw to push the rails all the way in. Just a thought and a few things to look at. Please let us know what you find.
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post #4 of (permalink) Old 11-19-2002, 01:35 PM
Blazer1970
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Re: NP 205 won\'t go into low range

</font><blockquote><font class="small">In reply to:</font><hr />
Please correct me if I'm wrong, but I don't believe an auto/205 combo was origionally put in anything '72.

[/ QUOTE ]

You are wrong. TH350/NP205 was the standard set-up for 1972. Not much to go wrong in the linkage, but if you crawl under the truck and look, you should be able to see if there is a problem. You can push/pull on the shift rails in the t-case directly to determine if stuff is moving like it should be. Otherwise, it is an internal problem in the t-case. They can be hard to shift at times, it sometimes helps to put the truck in neutral, or to shift it while rolling slowly.
post #5 of (permalink) Old 11-19-2002, 06:23 PM
tjayandlisa
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Re: NP 205 won\'t go into low range

</font><blockquote><font class="small">In reply to:</font><hr />
Does the truck have body lift or anything?

[/ QUOTE ]

As mnorby said...Body lifts are the most common hang up! Wont allow the throw need for shifter...lengthen the shifter if hitting the body
post #6 of (permalink) Old 11-20-2002, 07:07 PM Thread Starter
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Re: NP 205 won\'t go into low range

Duh - found it - shifter was really dirty and greasy underneath.
Sprayed it down with a pressure washer - twice.
Used brake cleaner too.
Still a big gob of grease on it.

Had a friend trying to move it from up top while I was
underneath.
I poked the huge gob of grease with a screwdriver - felt
solid.
Hit it, out popped a rock, black, dirty, and the perfect shape
to keep it from shifting! Not a gob of grease after all.
You'd never find one like that if you tried!

Thanks!

Next question - the big round plate on the back - it's just
a cover plate, or more than that?

Reason I ask is it's leaking ATF.
ATF? Is that what's supposed to be in there? Every x-fer
case I've ever dealt with uses 90 WT.

Might I have an auto tranny/x-fer case seal problem?
Or the PO didn't know better?

NP205 / 350 auto.

Thanks again

Always had Jeeps before.



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post #7 of (permalink) Old 11-20-2002, 07:22 PM
tjayandlisa
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Re: NP 205 won\'t go into low range

140 wt gear oil in the 205....atf for chain driven tcases...
post #8 of (permalink) Old 11-20-2002, 09:48 PM
87sm465np208
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Re: NP 205 won\'t go into low range

12 bolts are pretty stout 1\2 ton rearends, yes. i put one in my truck because i blew out the 10 bolt gov-loc. the way to go lower is to put the gears you want in the diffs's, or pay to have it done. glad to hear that you got that rock out of your case. good luck with the truck, sounds very solid from your discription, 205's are great T-cases.
post #9 of (permalink) Old 11-21-2002, 07:31 AM
Blazer1970
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Re: NP 205 won\'t go into low range

The round cover plate on the back also is the support for the back end of the front output shaft. Your case was specified to use 90 wt. gear oil. It is very common for the o-ring and seal in the adapter between the tranny and t-case to fail, allowing ATF to leak from the tranny back into the t-case, and that is likely what is happening on yours. It won't hurt the 205 to run on ATF if you don't want to pull the t-case to fix that seal right away.
post #10 of (permalink) Old 11-21-2002, 03:29 PM
muddfred
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Re: NP 205 won\'t go into low range

If tranny fluid still comes out of the 205 after you change to 90 weight, it is coming from the tranny through the seal at the output of the tranny. If this is happening it will cause problems because the tranny will pump the fluid all into the transfer case. It won't hurt the transfer case but the trany doesn't work too good without fluid. This happened to me when I used the 350/205 combo. It started right after the tranny was rebuilt.
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