What's new

NP205's sometimes bring the suck

06h3

Red Skull Member
Joined
Sep 8, 2020
Member Number
2843
Messages
1,483
Loc
SW Idaho
Why does everyone love NP205's? They are strong and 90% of the people who use 205's today mate it with a doubler box to get good range options but I did learn quite a few downsides after setting one up in my rig and thought I would share.

I notice the aftermarket flanges are machined at 2.125 and it happens to be that the seals are 2.125. It makes a shitty seal and driving down the highway the thing would leak. After doing research I noticed most seals are undersized compared to the yoke about .015. I did find a speedi-sleeve to put over a brand new yoke to enlarge the yoke seal surface .011 which hopefully will solve that issue (haven't put many miles on it yet since that fix) not a big deal but I have never seen that complaint before but when I started asking people with 205's they just said oh yeah, they always leak out the output seal on the road after the seal has some miles on it....

MPG. I don't give two shits about mpg but I do care about range driving to and from the trail on longer trips. My fuel range took a huge hit going from a chain case to a 205. I get it, its thicker oil, way more drag, etc and I was expecting some loss but losing anywhere from 20-30 miles per tank on the highway is a big hit and way more then I expected. With the range of 220 miles to begin with that is the difference between me running out of fuel in remote areas of NV vs. not running out of fuel. The fuel stops are few and far between in Eastern NV. I thought I would lose 5-10 miles per tank. I did ask others who drive their rig to and from the trail and they reported anywhere from 1-3 mpg loss depending on highway vs city driving. 1-3 mpg loss when you start with 10 mpg is CRAZY!! How do you take a 10-30% loss in MPG?!?

Shifting. I have a cable shifter (maybe thats my problem?) but damn I was excited to have the ability to do a front dig with ease but the damn thing is a PAIN IN THE ASS to shift. I did add adjustable detents and am trying some techniques to help make it easier but I am told its more of an issue with the non synchro gears from research.

Anyways, I see some pros like cost vs an atlas or hero case but its not as big as one would think once you factor in the doubler.

Pure strength, I don't think there is any question that an NP205 is stronger then an atlas. U4 cars have had their issues with Atlas t cases (they did come out with a race case to fix this) but some U4 cars are running 205's without issue. Mountain Havoc guys run 900 hp through them and are pushing 50+in AG tires and 7-8k lbs in weight with no issue. I think the 205 without a doubt wins this spot everytime. If you need pure strength this is the way to go.

I don't have experience with atlas cases but if you need more strength then a chain case but not pushing 800 hp and 54s you can probably use the atlas without issue. It may be worth the added expense if the atlas doesn't have the listed issues above.


I understand some of the issues are more street driven issues but can still be a PITA when moving at speed to and from the trail.

Curious if I will be ridiculed and called a pussy or if these are legit 205 issues no one talks about. 🖕😀🖕
 
Last edited:
One note to join into the conversation, is the low range. Factory low range is basically useless for trail rigs. To fix this you add a dubbler which has basically no fluid capacity or cooling compared to an Atlas or Hero where everything is in the same case and oil bathed.
 
I hate cable shifters. I'm still surprised when I see people using them. I always thought they would be a tread that would die quickly.

I helped a buddy build a twin stick for his 205 years ago. We did make the shifters pretty tall, but he had almost no problems shifting. Obviously if you are bound the fuck up, you might need to rock the vehicle to release the bind. This won't be any better with any case other than a lovell. Unless hero has some crazy shit I'm not aware of. Many atlas cases are super hard to shift also.

Comparing the price of a doubler/205 to a 2spd atlas isn't really a fair comparison. A single low range sucks for most trail rigs imo. I'll never own a crawler without a doubler. The 4spd atlas is obviously available, and nice, but way beyond the price point of a 205 and doubler box.
 
What oil are you running? Everyone seems to default to gear oil in a NP205, but you can actually run SAE 30 motor oil, which will free it up a bit.
 
I am running gear oil. I thought of trying out ATF since some did come with it but SAE30 sounds like a nice middle ground.

Did you have air shifters yotaatietoo? I looked into electric linear actuators but the height required to make them fit would have caused more issues. If you were the guy running air shifters, or whoever it was I remember them loving the air shifters as it applies constant pressure to shift so if/when it was bound up, it would shift once the bind was off. Currently it’s a PITA for me to even shift on flat ground. my fear is having an issue or air leak and not having easy access to fix it on the trail.

I’m with you, I don’t like cable shifters, I think they stick around because they are much easier to package. Newer vehicles can be a PITA to package traditional shift levers.

The lack of fluid is interesting and stupid but in its defense they don’t seem to care with only .5 quart of fluid but if you form a leak, there isn’t much there for backup. NWF is CNCing scallops in their new cases to allow for additional fluid which is pretty trick.

I know a guy who worked with NWF to help stop the fluid from exiting the breather/getting more fluid. They tried ditching the trans seal so the trans shares fluid with the doubler box. That had issues on steep climbs and losing fluid in the trans causing slippage, then a blockage tray to prevent fluid coming out the breather, that didn’t work. It seemed the best bet was a catch can so any fluid that came out eventually ran back in.

I can’t blame the doubler for lack of fluid, the atlas is the same way. It’s just the only design that has been used for all doublers.
 
I have a hard time believing a np205 is 30% parasitic loss over any other transfer case. Folks dont report that with gear driven doubler.
 
I am running gear oil. I thought of trying out ATF since some did come with it but SAE30 sounds like a nice middle ground.

Did you have air shifters yotaatietoo? I looked into electric linear actuators but the height required to make them fit would have caused more issues. If you were the guy running air shifters, or whoever it was I remember them loving the air shifters as it applies constant pressure to shift so if/when it was bound up, it would shift once the bind was off. Currently it’s a PITA for me to even shift on flat ground. my fear is having an issue or air leak and not having easy access to fix it on the trail.

I’m with you, I don’t like cable shifters, I think they stick around because they are much easier to package. Newer vehicles can be a PITA to package traditional shift levers.

The lack of fluid is interesting and stupid but in its defense they don’t seem to care with only .5 quart of fluid but if you form a leak, there isn’t much there for backup. NWF is CNCing scallops in their new cases to allow for additional fluid which is pretty trick.

I know a guy who worked with NWF to help stop the fluid from exiting the breather/getting more fluid. They tried ditching the trans seal so the trans shares fluid with the doubler box. That had issues on steep climbs and losing fluid in the trans causing slippage, then a blockage tray to prevent fluid coming out the breather, that didn’t work. It seemed the best bet was a catch can so any fluid that came out eventually ran back in.

I can’t blame the doubler for lack of fluid, the atlas is the same way. It’s just the only design that has been used for all doublers.

Not me, you're thinking of patooee or something like that, can't remember the exact spelling.
 
I have a hard time believing a np205 is 30% parasitic loss over any other transfer case. Folks dont report that with gear driven doubler.

I can confidently say I have received a 11% loss in mpg from going to a NP205 doubler. That is all highway driving. It’s the only time I track mileage/mpg when driving to and from the trail on longer road trips (500+ miles)

Others have claimed up to 3 mpg loss around the city.
 
Ive had my 203/205 doubler in since '05, and dont have issues with it leaking at the yokes. At some point (maybe 9-10 years ago) i switched to a flange for the rear output and same thing, no issues with it leaking. So not sure why you are having problems with it, unless the newer flanges just arent being made correctly.

I helped a buddy build a twin stick for his 205 years ago. We did make the shifters pretty tall, but he had almost no problems shifting. Obviously if you are bound the fuck up, you might need to rock the vehicle to release the bind. This won't be any better with any case other than a lovell. Unless hero has some crazy shit I'm not aware of. Many atlas cases are super hard to shift also.


I agree with this. Sure it can be a pain to shift occasionally, but i cant think of any case thats going to shift effortlessly all the time. The only time its an issue for me is when i want to do a front dig and cant get the rear output to go into N, but simply shifting thru N and back into gear (in the trans) is usually all i need and i can get it to disengage. Ive never been in a situation where it actually caused anything other than a minor inconvenience. Maybe some of the issue is your cable shifters; i have been running ORD's shifters the whole time and havent really had any problem with them.


Cant comment on the MPGs at all, it went in the same time as the tons and 42s. Maybe changing to better or different weight oil will help, but i cant see ever getting a gear driven case to be as efficient as a chain driven case running ATF.
 
Last edited:
Ive had my 203/205 doubler in since '05, and dont have issues with it leaking at the yokes. At some point (maybe 9-10 years ago) i switched to a flange for the rear output and same thing, no issues with it leaking. So not sure why you are having problems with it, unless the newer flanges just arent being made correctly.




I agree with this. Sure it can be a pain to shift occasionally, but i cant think of any case thats going to shift effortlessly all the time. The only time its an issue for me is when i want to do a front dig and cant get the rear output to go into N, but simply shifting thru N and back into gear (in the trans) is usually all i need and i can get it to disengage. Ive never been in a situation where it actually caused anything other than a minor inconvenience. Maybe some of the issue is your cable shifters; i have been running ORD's shifters the whole time and havent really had any problem with them.


Cant comment on the MPGs at all, it went in the same time as the tons and 42s. Maybe changing to better or different weight oil will help, but i cant see ever getting a gear driven case to be as efficient as a chain driven case running ATF.

Interesting, maybe they made some changes to the yoke seal surface. I know the one I have is 2.125 and a few others I have talked to have had similar leaking issues.
 
Interesting, maybe they made some changes to the yoke seal surface. I know the one I have is 2.125 and a few others I have talked to have had similar leaking issues.

NorthernDrivetrain makes these and takes care of customers, might be worth checking out. I've had his yokes on my Atlas for a decade and have been leak free, which are identical to NP205 yokes sans a little pilot angle.
 
What oil are you running? Everyone seems to default to gear oil in a NP205, but you can actually run SAE 30 motor oil, which will free it up a bit.

Hell you can run ATF in them even. Later model ones behind autos ran atf in them factory.
 
Hell you can run ATF in them even. Later model ones behind autos ran atf in them factory.

Maybe a fresh rebuild. All the Dodge ones I am familiar with call for at least motor oil and tend to make a lot of noise with ATF and leak like hell. But then, I never rebuilt one and will just swap in another used one if one goes bad. I wanted to try synthetic just for some piece of mind in the winter months, but I know that would probably leak out as well. But my old 150k+ mile 205s aren't exactly the same as a nice one rebuilt with all the fancy billet goodies bolted on, doublers and all. Plus I run 80W90 in my 4 speed, so one fluid sort of makes it simpler to carry spare lube.
 
Never run one and have no experince, but never heard of all your problems. Funny though, there's a guy on FSB that has a broken 205 case as his avatar. He broke two of them and says their not as strong as people think. (Not running 900hp) Got to say, hard to believe 30% mpg loss.
 
and sometimes(actually its usually) np205s are the most reliable strongest problem free part on the entire truck

np205s are like cummins, one of the best things things ever put in a light duty truck :grinpimp:, just about the only two stock parts left on my truck :laughing:
 
Never run one and have no experince, but never heard of all your problems. Funny though, there's a guy on FSB that has a broken 205 case as his avatar. He broke two of them and says their not as strong as people think. (Not running 900hp) Got to say, hard to believe 30% mpg loss.

I bet the guy on FSB had it mounted wrong or his driveshaft plunge was fucked and kept smashing the case.
 
I bet the guy on FSB had it mounted wrong or his driveshaft plunge was fucked and kept smashing the case.

I bet he's getting airborne and shock loading it. There's a guy on GoFastBroncos who split a couple NP435s that way.

The 205 should kill the transmission adapter long before the case breaks. The trans adapter necks down pretty small and, the 205 has a whole lot of leverage on it and the case is built to handle force trying to pull it apart like that (which is what the shafts do every time you put power through them)
 
Never run one and have no experince, but never heard of all your problems. Funny though, there's a guy on FSB that has a broken 205 case as his avatar. He broke two of them and says their not as strong as people think. (Not running 900hp) Got to say, hard to believe 30% mpg loss.

I wonder how many issues arise from improper twin stick / detent / shifter modifications. Example when he sends his dumpster into the sky, the shifter binds up and self shifts the front different than the back and boom.
Break one, maybe a bad part, break two, there's probable something else causing the issue.
 
Yea, I agree something has to be shock loading the system for a 205 to break like that.
 
90% of the time I'm hauling ass with the 205 in 2wd low range and throw the front axle in on the fly no problem. Shifting the front planetary box is the easiest to shift just have to stop first.
 
90% of the time I'm hauling ass with the 205 in 2wd low range and throw the front axle in on the fly no problem. Shifting the front planetary box is the easiest to shift just have to stop first.

Can you or anybody list the sequence of shifting a 205 with a planetary doubler in front.
What can you shift on the fly.
What do you need to stop for.
What do you need to shift the trans in or out of neutral for.
What do you need to be rolling to shift.
The more the better.

The reason I ask is I planned to use air shifters, but am now thinking of doing linkage.
 
Can you or anybody list the sequence of shifting a 205 with a planetary doubler in front.
What can you shift on the fly.
What do you need to stop for.
What do you need to shift the trans in or out of neutral for.
What do you need to be rolling to shift.
The more the better.

The reason I ask is I planned to use air shifters, but am now thinking of doing linkage.

Try to answer best I can. The twin stick 205 can be shifted on the fly within reason.

If you are running the 205 with the front in neutral and the rear in low you are 2wd low. With the rear in low you can shift the front into low or neutral on the fly. Same works for the rear you can run front wheel drive low and kick the rear into neutral.

You have to stop when shifting between ranges high to low or low to high. Also you don't want to shift the front and rear into different ranges. When shifting the planetary box you have to stop or barely moving.

Hope that makes sense
 
When shifting the 205 on the fly, the front and rear driveshaft speeds need to match. You cant be stuck in a hole doing a 2wd burnout at 5000 rpm and engage the front axle. Shit go grindy grindy then boom. :flipoff2:
 
and sometimes(actually its usually) np205s are the most reliable strongest problem free part on the entire truck

np205s are like cummins, one of the best things things ever put in a light duty truck :grinpimp:, just about the only two stock parts left on my truck :laughing:

I’m shocked I wasn’t really ridiculed. You have the honors! Go for it
 
I’m shocked I wasn’t really ridiculed. You have the honors! Go for it

its because everyone knows its one of the best transfer cases ever made and its a waste of time to try and argue about it not being a piece of shit :flipoff2:

mine happens to come from the factory with 32 spline outputs frt and rr :smokin:
 
its because everyone knows its one of the best transfer cases ever made and its a waste of time to try and argue about it not being a piece of shit :flipoff2:

mine happens to come from the factory with 32 spline outputs frt and rr :smokin:

mine does too...all Ford 205s did from my reading. honestly not sure what make you're running though.
 
Since we spoke on IG briefly about this, I'm glad I found thsi thread. I just got back (last week) from UA and I ended up having to change out my output seals on the way out (not sure if the culprit was the front or rear) because it was coating the underside and tailgate of the truck in gear lube. I have a Ford NP205 in mine with an NWF EcoBox. The seals were about 2 years old and I'm running an NP241 short flange output on the front (1.75" sealing surface) and a NorthernDrivetrain 1410 yoke for the rear output (2.125" sealing surface). They were only weeping before I departed, but I hadn't done a super long road trip like this in some time so I'm guessing once the fluid thinned out, it slipped past the seal much easier. Luckily they're easy to change with just the yoke removed and a pry bar + hammer.

EcoBox: Anyway... I'm one of the guys running an NWF EcoBox with the fluid provided by the transmission. I have a tee at the transmission cooler return line and a .050" orifice to divert most of the trans fluid back into the trans. The front input seal on the EcoBox is removed so the fluid flows back into the transmission and the only breather on the whole EcoBox/Trans system is the factory trans breather. For a while I was having issues with the transmission losing fluid pressure on steep climbs due to the fluid flowing back into the EcoBox, but I now have the trans fluid overfilled by about a quart or maybe more and it's not an issue any longer. I'm very happy with this setup because it's essentially maintenance free.

Seals: The 205 obviously is not. 2 years from a seal isn't awful, but it's not great and it frankly never was perfectly dry. Not sure what brand my previous seals were, but they felt cheap. This go-around I've got National and SKF and it seems to be bone-dry after my trip back. If these only last a couple years before they start weeping again, I'll try the speedisleeve you're using.

As a result of the EcoBox and flat belly, my 205 is clocked up pretty flat. I'm running 3 quarts of 75w-90 Synthetic, so the level is much closer to the rear output while it's spinning - may have something to do with it.

Shifting: As for shifting - I agree with what's been said so far. Hit it with your purse... but also shift the trans between D, N, and R when trying to disable the rear output. I've also got JB Fab cable shifters with adjustable detents and I can usually get it to disengage the rear output by going into neutral on the trans WHILE putting pressure on the shift lever.

Fuel mileage: I'm one of the guys who checks fuel mileage around town. My data is slightly skewed because I moved to a 4L80E from 4L60E when I did the doubler swap, too. But beforehand, I was getting over 13mpg on the highway and now I'm lucky to get 11.5mpg. I don't care much about mileage or range, so I just deal with it - I just have the data so it's here to share. In town with gear lube in the 205, I can tell on cold days the truck isn't quite as peppy as it was with my NP241. I think the gear lube splashing against 6 gears in the NP205 really pulls a lot of efficiency out of the drivetrain, as I've gotten as low as 8.5mpg in town in a cold month. I never dropped into the single digits with the old trans/t-case setup. Same gears and tires.

Conclusion: The bottom line for me is the dig ability is the only reason I keep the NP205. With an EcoBox (instead of a Blackbox or Magnum) I have the ability and have been tempted to move to an NV271 instead for lower double-low range (7.4:1 instead of 5.33:1), but I'd definitely miss the ability to do front digs with my long wheelbase truck. I have no doubts that the NV271 would be strong enough for my (and Chris's H3) application after seeing the abuse they take under diesel pulling trucks. I'd probably pick up some fuel mileage going to a chain-driven case, too.
 
Since we spoke on IG briefly about this, I'm glad I found thsi thread. I just got back (last week) from UA and I ended up having to change out my output seals on the way out (not sure if the culprit was the front or rear) because it was coating the underside and tailgate of the truck in gear lube. I have a Ford NP205 in mine with an NWF EcoBox. The seals were about 2 years old and I'm running an NP241 short flange output on the front (1.75" sealing surface) and a NorthernDrivetrain 1410 yoke for the rear output (2.125" sealing surface). They were only weeping before I departed, but I hadn't done a super long road trip like this in some time so I'm guessing once the fluid thinned out, it slipped past the seal much easier. Luckily they're easy to change with just the yoke removed and a pry bar + hammer.

EcoBox: Anyway... I'm one of the guys running an NWF EcoBox with the fluid provided by the transmission. I have a tee at the transmission cooler return line and a .050" orifice to divert most of the trans fluid back into the trans. The front input seal on the EcoBox is removed so the fluid flows back into the transmission and the only breather on the whole EcoBox/Trans system is the factory trans breather. For a while I was having issues with the transmission losing fluid pressure on steep climbs due to the fluid flowing back into the EcoBox, but I now have the trans fluid overfilled by about a quart or maybe more and it's not an issue any longer. I'm very happy with this setup because it's essentially maintenance free.

Seals: The 205 obviously is not. 2 years from a seal isn't awful, but it's not great and it frankly never was perfectly dry. Not sure what brand my previous seals were, but they felt cheap. This go-around I've got National and SKF and it seems to be bone-dry after my trip back. If these only last a couple years before they start weeping again, I'll try the speedisleeve you're using.

As a result of the EcoBox and flat belly, my 205 is clocked up pretty flat. I'm running 3 quarts of 75w-90 Synthetic, so the level is much closer to the rear output while it's spinning - may have something to do with it.

Shifting: As for shifting - I agree with what's been said so far. Hit it with your purse... but also shift the trans between D, N, and R when trying to disable the rear output. I've also got JB Fab cable shifters with adjustable detents and I can usually get it to disengage the rear output by going into neutral on the trans WHILE putting pressure on the shift lever.

Fuel mileage: I'm one of the guys who checks fuel mileage around town. My data is slightly skewed because I moved to a 4L80E from 4L60E when I did the doubler swap, too. But beforehand, I was getting over 13mpg on the highway and now I'm lucky to get 11.5mpg. I don't care much about mileage or range, so I just deal with it - I just have the data so it's here to share. In town with gear lube in the 205, I can tell on cold days the truck isn't quite as peppy as it was with my NP241. I think the gear lube splashing against 6 gears in the NP205 really pulls a lot of efficiency out of the drivetrain, as I've gotten as low as 8.5mpg in town in a cold month. I never dropped into the single digits with the old trans/t-case setup. Same gears and tires.

Conclusion: The bottom line for me is the dig ability is the only reason I keep the NP205. With an EcoBox (instead of a Blackbox or Magnum) I have the ability and have been tempted to move to an NV271 instead for lower double-low range (7.4:1 instead of 5.33:1), but I'd definitely miss the ability to do front digs with my long wheelbase truck. I have no doubts that the NV271 would be strong enough for my (and Chris's H3) application after seeing the abuse they take under diesel pulling trucks. I'd probably pick up some fuel mileage going to a chain-driven case, too.

I have contemplated a 271 but still want to mess with the front digs. I think that will help on the trail. I tried a speedi sleeve and a new seal. So far it is bone dry but it only has 100-110 highway miles on it, one wheeling trip and probably 30-40 around town miles. I will report back on that long term but I think that the speedi sleeve will help as it gets the specs much closer to other yoke to seal surfaces.

With all that said, the strength is insane as I saw guys this past weekend at Idaho Tuff Truck challange launch 8k lb rigs on 54s and big hopped us LS power just put a beating on those 205s and they took it. I cant imagine with my weight and tire size that I would ever be able to ruin a 205 unless I ran it without oil and had too long of a driveshaft and kept bottoming it out on the case.

How long have you had your transmission/doubler box setup like that? No issues with it being overfilled?
 
I've had the shared transmission fluid setup since I installed it (2+ years ago). At first I just had the trans cooler line tee'd with no orifice, but Bowman suggested my transmission would be happier if I put an orifice. We discussed a check-valve on the return port on the transmission to keep even more fluid in the trans during steep climbs but I haven't gotten around to finding one that'll work and since it's working fine overfilled, I'm not too concerned with it.

It's been overfilled for at least a year and over 10k miles, with three cross-country trips included. No issues. Someday I'll have to mark the dipstick so I know what the current fill height is. I can't confirm if the same will be true for a 60/65e.
 
Top Back Refresh