73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => 4 Wheel Drives => Topic started by: treestandjunkie on March 12, 2010, 06:37:50 pm

Title: Np 205 question
Post by: treestandjunkie on March 12, 2010, 06:37:50 pm
I have a question. I am ignorant when it comes to old school 4x4's. will it hurt anything to drive with the transfer engaged in 4 hi and the hubs on free? My shifter has a ton of slack in it so it is hard to tell if it is engaged. I drove about 40 miles or so and got out to check the truck and found trans fluid blown everywhere and dripping from the transfer case. There was quite a bit on the bottom of the cab just above a tube that comes out of the top of the transfer case. So any help this dummy can get would be greatly appreciated. Where are you Vilezambonie??LOL!!
Title: Re: Np 205 question
Post by: Blazin on March 13, 2010, 02:38:16 pm
Shouldn't drive it shifted into 4x4 even if the hubs are out.
Title: Re: Np 205 question
Post by: VileZambonie on March 14, 2010, 12:03:08 am
So you have an automatic trans and your transfer case is only working in 4Hi? And when you drive your seeing atf come out of the transfer case? ??? Clarify please what you have and exactly what is happening
Title: Re: Np 205 question
Post by: treestandjunkie on March 14, 2010, 12:51:03 am
Hey vilezambonie i sent you a pm.
Title: Re: Np 205 question
Post by: treestandjunkie on March 14, 2010, 01:03:05 am
When i took it out of 4wd and tried to put it in park it would grind. I cant tell exactly where the fluid is coming from but the transmission is clean. There is a short tube that comes out of the top of the transfer case so i was wondering if it might have came out of there. Will it hurt to have atf in the transfer? I havnt had the truck very long so i am starting to find all kinds of stuff that needs to be done. Dont know much about older 4x4's so whatever help i can get i would appreciate.
Title: Re: Np 205 question
Post by: VileZambonie on March 14, 2010, 11:43:26 am
If you're leaking ATF into the transfercase it will be overfull and your transmission will be low. Check the tranny fluid and pull the check/fill plug on the transfer
Title: Re: Np 205 question
Post by: treestandjunkie on March 14, 2010, 01:25:22 pm
Yes Vile my transmission is low and my transfer case is over full. How hard is this to fix??
Title: Re: Np 205 question
Post by: VileZambonie on March 14, 2010, 02:29:09 pm
You'll need to replace the input seal on the transfer case. Basically witness mark your driveshafts, remove them, drain the T-case and drop it. Change the input seal and put it back together. Make sure you don't run your trans low.
Title: Re: np 205 ????
Post by: Engineer on March 14, 2010, 03:41:17 pm
Driving with the transfer engaged, and hubs disengaged shouldn't have hurt anything.

The way that a NP205 is built all of the gears in the t-case turn all of the time with the input shaft any how. Only thing that is not turning when the NP205 is in 2WD is the front output shaft.

They do this so as to keep a flow of oil to the bearings on the input, and rear output shaft.

Don't know what would cause your oil loss though.
Title: Re: Np 205 question
Post by: Engineer on March 14, 2010, 03:56:21 pm
I'll respond here to add to this thread.

OP has this thread running in the engine/drivetrain forum as well.



Driving with the transfer engaged, and hubs disengaged shouldn't have hurt anything.

The way that a NP205 is built all of the gears in the t-case turn all of the time with the input shaft any how. Only thing that is not turning when the NP205 is in 2WD is the front output shaft it'self.

They do this so as to keep a flow of oil to the bearings on the input, and rear output shaft.

You'll need to replace the input seal on the transfer case. Basically witness mark your driveshafts, remove them, drain the T-case and drop it. Change the input seal and put it back together. Make sure you don't run your trans low.

There is not an input shaft seal per-se. The seal that keeps the tranny fluid, and transfer case fluid separate is located in the transfer case mounting adapter.

Some of the later NP205s used ATF, so I doubt that you have harmed it in any way.
Title: Re: Np 205 question
Post by: VileZambonie on March 14, 2010, 08:59:08 pm
There's not an input shaft seal? Then what do you call the input shaft seal? ???
Title: newbie question
Post by: treestandjunkie on March 16, 2010, 06:02:00 pm
I searched the forum and failed to find it. I am going to replace the seal that goes between the transmission and the transfer case. How much gear oil will i need for my np205?? And will I need trans fluid as well? Thanks for your help. P.S. Is there any special tools I might need?
Title: Re: newbie question
Post by: treestandjunkie on March 16, 2010, 06:16:37 pm
And there are multiple debates about gear oil and atf? Suggestions please ???
Title: Re: newbie question
Post by: highsierra86 on March 16, 2010, 08:09:19 pm
I'm no expert but I do work at a GM dealer we use ATF so that's what I use
Title: Re: newbie question
Post by: Irish_Alley on March 16, 2010, 08:35:48 pm
If you stick to one topic instead of making multiple ones for the same question you will find you will get more help on questions
Title: Re: newbie question
Post by: joesgarage71 on March 16, 2010, 09:17:10 pm
NP-205 2.5 Qts. prior to 1980 use 85W-90W gl-5 gear lube after 80 use Dextron. change the trany filter and pan oil too.
 Steve
Title: Re: Np 205 question
Post by: Engineer on March 17, 2010, 09:13:33 pm
There's not an input shaft seal? Then what do you call the input shaft seal? ???

All I have ever heard it called was an "adapter seal".

I know, not much help.
Title: Re: Np 205 question
Post by: treestandjunkie on March 18, 2010, 04:03:09 pm
Thanks to all who had some advise for a dummy!!