NP205 question

[mastermechanic19]

http://www.wheelindixie.com/forums/s...92-np-205-info

You can also search for np-205 on pirate 4x4 and read for days....

[ddarnell]

Great info.
My original question stems from what I believe to be a noisy TC. Research has revealed that most consider the gear driven NP205 to be quiet as a mouse, mine is not. Or at least I believe it's the TC. The noise sounds to be a gear lash/mating type sound, occuring during accel and deccel, with relative silence at that mid point of a throttle lift where the drivetrain is neither loaded by application of power or engine braking. It's so difficult to pinpoint these types of noise as it can be telegraphed from some other component.
Perhaps a worn input/output shaft bearing is causing a change in the gear mating?
Just don't know at this point. I really prefer a solid diagnosis before buying parts. My (former) staff mechanic told me it was the chain, well the NP205 has no chain. LOL Several Dodge experts told me the same thing, as a 1976 W200 only came with a NP203.
I have positively identified the TC as a NP205. so I looking for a direction.
Thanks for all your great input!
David

[KRB64]

So that is not stock and you do not have full time 4X4 correct? Just making sure we are all on the same page here.

[ddarnell]

Wouldn't know if it is stock, other than it's supposed to have an NP203. I do have locking hubs, it's not full time. Heck I thought the long bed wasn't stock either (it's a crew cab) but the VIN says it is.
It's an ugly beast that I'm slowly but surely going through to make it reliable and fully functional.
David

[USN78W150]

205

When was the last time you checked the universal joints? One or more could have enough free play to transmit a lot of noise throughout he system. Another thing to check would be the parts used to convert to the 205. Does the transfer case cross member look factory, or homemade? The case placement may possibly be slightly off center, causing u joint angle issues. I would love to know the first six digits of your VIN number, as there are no long bed Crew Cab 4x4's made at the factory. I heard a rumor over twenty years ago that Pathfinder (the company who brought us 4x4 full size vans) did some 4x4 conversions on long bed Crew Cab Dodges from '75 to about '79 or '80. Another thing to check is if the VIN number on your truck's frame matches the one on the door jamb of the cab.

[KRB64]

Long bed 4X4 crew, does sound like an interesting beast. Somebody did some tinkering.

I agree, check and make sure that the coversion(s) was done correctly. If it started life as a D200 then there are front driveshaft angles that can transmit to the TC. Plus if the TC started as a 203 theres the quality of the conversion that USN78W150 eluded to.

I hate cleaning up what POs cobbled up.

[ddarnell]

The VIN is W26BF65231046. The TC mounting appears to be factory, a formed metal piece. U-joint play is not excessive, though I will be replacing them for general purposes. I have not checked for wear/play in the rear end.
David

[MoparNorm]

Great info.
My original question stems from what I believe to be a noisy TC. Research has revealed that most consider the gear driven NP205 to be quiet as a mouse, mine is not. Or at least I believe it's the TC. The noise sounds to be a gear lash/mating type sound, occuring during accel and deccel, with relative silence at that mid point of a throttle lift where the drivetrain is neither loaded by application of power or engine braking. It's so difficult to pinpoint these types of noise as it can be telegraphed from some other component.
Perhaps a worn input/output shaft bearing is causing a change in the gear mating?
Just don't know at this point. I really prefer a solid diagnosis before buying parts. My (former) staff mechanic told me it was the chain, well the NP205 has no chain. LOL Several Dodge experts told me the same thing, as a 1976 W200 only came with a NP203.
I have positively identified the TC as a NP205. so I looking for a direction.
Thanks for all your great input!
David

NP205


NP203


I don't know just how "quiet" a 205 can be, both my 205 and 201 make a pretty good racket up through the shift lever (s) with the 205 being marginally quieter. But depending upon if you are in low range or not, there is a noticeable gear whirl. These aren't Imperials... = )

[ddarnell]

So you say your 205 has a noticable gear whine/whir? Is it at it's quietest during the transition from throttle application or throttle lift? Or is it constant? Heck, maybe mine is making a perfectly normal amount of noise. I read a number of things that suggest the lack of a chain made the 205 significantly quieter than the 203.
Mine is quite a bit louder during throttle application or throttle lift, with a noticably quieter operation in that midpoint between accel or deccel.
It seems to me that if the lash/play were correct that I would not have the difference in noise output, but it's all conjecture on my part
David

[mattsoldmopars]

Honestly on this particular subject, its mostly in my head. So much misinformation is out there in Chiltons/Haynes manuals, at least concerning what years certain t-cases were used by Dodge.

Concerning Dodge's use of the NP205:
1969-1974 was used in W100,200,300 as a divorced setup.
1975-79 not available in Dodge.
1980 used in all W series
1981-later used in some W250's & most/all W350's until the 241 came out.

Some Fords of the 60's used Dana's & maybe Borg-Warner's too. And GM's had a Rockwell T221 somewhere in the 60's.

I have owned/read alot of reference books over the years. I wished I still had most of them.

I have owned a dozen or so 1972-1979 Dodge W series trucks. I am comfortable working on them.

Bucky

Bucky, With so much misinformation out I just want to clear up one thing from your post of the years dodge used the np205,

"1980 used in all W series"

NOT true, 1980 was the first year dodge used the married np205 yes, but only in the H.D. 3/4-tons and the 1-tons, the light duty/lower GVW 3/4-ton and the all 1/2-tons used the part time, aluminum 208 t-case

I have owned 2 1980 4x4 dodges and parted a 3rd one out.

1980 was also the first year dodge went back to the part time 4x4 after the full-time years of 1975-1979 as you mentioned.


Matt

[MoparNorm]

So you say your 205 has a noticable gear whine/whir? Is it at it's quietest during the transition from throttle application or throttle lift? Or is it constant? Heck, maybe mine is making a perfectly normal amount of noise. I read a number of things that suggest the lack of a chain made the 205 significantly quieter than the 203.

Mine is quite a bit louder during throttle application or throttle lift, with a noticably quieter operation in that midpoint between accel or deccel.

It seems to me that if the lash/play were correct that I would not have the difference in noise output, but it's all conjecture on my part
David

The gear cases are noisier than the chain cases, it's one of the reasons they went to chains. Acceptable noise in 2WD High Range, it gets louder in 4WD and louder yet in Low Range because you have more gears participating and low range gears are spinning faster.

Now, when it comes to excessive noise, is it coming from the shifter or from the case in general?

The shifter can act like a stethoscope and sometimes laying your hand on it will quiet it up and/or allow you to "feel" the vibration of a chipped gear tooth or worn bearings.

Just as you can diagnose a ring and pinion, you can also get a clue as to whether the noise is normal or a results of a poorly shimmed end play or a bad bearing, depending upon whether the noise is during load, on acceleration or on coast. All of those scenarios are an indication of which bearings, gears, or shafts may be the culprit. If you have a diagram, you can learn which shafts and gears and thus bearings, are carrying the load when in each gear selector position. That helps in narrowing down the area in which to look, however if the noise is severe, the location is usually self evident when you crack the case... = )

Now, all that being said, I've also opened very noisy cases only to find nothing visibly wrong, I've changed all the bearings, checked the end play and put them back together with the resulting noise being about equal. I have come to the point that if it's drivable and works, a t-case is fine until it is extremely obvious or you can hear the chain slapping the case... = )

[ddarnell]

Thanks Norm, you have helped me reach the same point. It is perfectly functional. I might drop it, crack it open and take a look or just run it the way it is. Fact is I don't put that many miles on it and I'm sure I can find other things to spend time and money on.

I will study the exploded view so I can get a handle on it.........gives me something to think about and visualize while I drive. Yeah I know it's a sickness but I like it.
Mery Christmas!
David

[Gordon Maney]

http://www.wheelindixie.com/forums/s...92-np-205-info

You can also search for np-205 on pirate 4x4 and read for days....

Really great link.

[MoparNorm]

Thanks Norm, you have helped me reach the same point. It is perfectly functional. I might drop it, crack it open and take a look or just run it the way it is. Fact is I don't put that many miles on it and I'm sure I can find other things to spend time and money on.

I will study the exploded view so I can get a handle on it.........gives me something to think about and visualize while I drive. Yeah I know it's a sickness but I like it.
Mery Christmas!
David

Merry Christmas! (and you can just wrap a sound blanket around it and call it good for another 10,000 miles...ha! ha!)
The one real shame of the internet is that I can't come over and listen to it and say, "Oh!, That is fine!" or "Uh oh, we'd better pull that open..."

[ddarnell]

LOL..........it is hard to describe some thing in a post. We're gonna plug the holes in the floor pan, throw some Raamat, padding and carpet on it and call it good!
Merry Christmas!
David