NP208 VS Dana 20/300, a professional opinion.

[FSJeeper]

There has been a very lively debate concerning strength differences of the NP208 and Dana 20/300.
Not only are these debates fun, but they are the sure cure for boredom.

I shot Mike Monahan an email and asked his opinion. Mike runs a 4x4 business, is a prolific 4x4 writer, and has been involved in 4x4's, the desert racing scene, rock crawling, etc., for 30 years. He probably has forgotten more about 4x4's than what we know. This is what he said:

The Dana 300 and model 20 were both designed for light duty vehicles, they are gear driven which is a plus, the output shafts are weak compared to the 208 fixed yoke units. The NP208 is a newer unit designed for pickups and SUV's. Strength wise as long as it is in good condition and has a fixed yoke the 208 is stronger and has a 2.72 to 1 ratio in low range. The NP241HD is being used in new Diesel trucks and is a close relative to the 208.

[River Beast]

IS there an upgrade kit to make the GM NP208 into a fixed yoke setup?

[FSJeeper]

I am pretty sure you can swap parts from a Ford or Jeep NP208 to make a fixed yoke case. Try searching the Pirate and ColoradoK5 boards. I'll dig around in my junk and see if I have some.

I learned something, I did not think the slip yoke rear was that big of a strength issue.

[Sycho15]

The NP-208 has a 2.61:1 low-range. The NP-231 and 241 (or 242) have the 2.72:1 low-range.

X-cases I've dealt with...
3 NP-208s (if you count the "bottomless x-case" that came as a parts piece with Timex)
2 NP-231s (both 21-spline input units behind Peugot BA-10 5-speed manuals tongue.gif )
1 NP-242

The Chevy NP-208 has a slip-yoke rear, passenger-side front output, but doesn't the Dodge NP-208 have a fixed-yoke rear, passenger-side front output?

[River Beast]

Ok..then I went to the ColoradK5 board and searched....and searched.... and searched... No SYE is available but a few talked talked of a guy that made one... dunno how and can't find the info...seems like most problems... besides the shift fork as you mentioned is the slip yoke on high angles....but not too common of an issue for me to really worry about right now...

[tuck]

Is the 208 an aluminum case?

[River Beast]

NP208 is aluminum

[TexasJ10]

Isn't the 241HD a slip yoke design as well. I think the 241LD has a slip yoke eliminator kit but not the 241HD. Chevy still uses the 241LD passenger side drop I think.

[scotty]

you can easily swap the jeep parts,but then you are giving up your 32 spline tailshaft,are you not?

asi see it,the only thing making the chevy 208 better than the jeep 208 is the 27 or 32 spline input.

youre still not convincing me,tho. smile.gif 'specially since your expert got the 208s low range wrong ;) tongue.gif

i have run a 219,a 207,a 208,a d300,and now my spicer 18. my 300 was by far means my favorite. my 219 started his chain slipping,my 207 eventually started popping out of 4 lo in reverse, and my 208 i didnt even run for very long cause it wouldnt shift right. at that point i said "enuff of this aluminum chain drive xfer case BS"

the 208 is strong for what it is,and a good one thats properly maintained will last most people just fine but you still: a)do not have lower low range options b) no twinstickability, and c) its longer. mt d300 with a klnue v crawler box in front of it would be very close in length to a 208.

and ill still say any gear drive case is gonna be more reliable in an EXTREME trail rig(500+horsies,39"+ tires) than an aluminum case that that drives BOTH outputs. but that wasnt part of the question,was it? ;)

your thots? smile.gif

let the debate continue... tongue.gif

[FSJeeper]

In the NP208, the chain drives only the front output shaft.

[porkchop]

I am curious what does the expert consider a light duty truck? I also have to agree that the gears will always be stronger. Not only that if a gear is to go out, happened to me, you may still be able to drive the rig and you will not lose the case in the process. When My main gear cracked a tooth I still drove it to work and was able to change out the gears that had damage on them and keep on trucking. The gears, or the whole case, can be found very cheaply. A chain is over a $100 and then if that breaks it has a really good chance of taking the case with it. Then what?

Plus I really love the twin stick :D .

[ September 10, 2002, 03:41 PM: Message edited by: porkchop ]

[FSJeeper]

There is no doubt gear driven tcases rule, but it is very possible some of them are stronger than the Dana 18/20/300.

[tuck]

Originally posted by FSJeeper:
There is no doubt gear driven tcases rule, but it is very possible some of them are stronger than the Dana 18/20/300.yeah, it's called a 205 :D

what's this talk about JB conversions making a lower gearset? I can only imagine what they'll charge for that... Think about it... stronger than an Atlas, twin-sticked, and has a decent low range... other than weight, and maybe a little lower gearing I can't see any advantages to going Atlas..

Oh, but we're talking about the np 208 aren't we? I personally am not going to swap out my D20 with new seals and joints for an aluminum, chain-drive t-case. Not worth the effort. I'd rather save money for a doubler or Atlas, or keep my Dana 20 until it goes boom, and band-aid it until the doubler or Atlas becomes a reality. Juss my $.02

[Stuka]

I am rebuilding my D20 here shortly, I dont see any reason to go to a aluminum case with a chain. I have had to do a few clutch drops in 4wd to get out of stuff..my D20 has held up just fine. I have twisted a front and rear drive shaft tho. And I am not running HUGE tires, but a V8 spinning 4 tires does put out a lot of force.

I still vote the D18/D20 over the 208. The 300 has that aluminum tail shaft housing..make it steel and I like it the most smile.gif

[kyrel]

well I do not know a lot about the 208 but I do know that my dana 20 is strong. I run a mildly build 360 t18 and and dana 20. 36in tires. I have broke 2 rear drive shafts in half. I have never had any probems out of my 20. I am even now running it with bronco dana 20 gears in it and no problems out of it at all. I would think that the dana 20 would be as strong as the 208 if not stronger. and if it does break they are a dime a dozen

[scotty]

Originally posted by FSJeeper:
In the NP208, the chain drives only the front output shaft.right,that was another QT reference. thats why i said "but that wasnt the question,was it" sorry for the confusion ;)

so whats the verdict on output splines? which output is stronger? the chevy slip yoke,or the jeep fixed yoke?

nother thing to keep in mind is that newer trucks with aluminum cases get away with it simply cause they spend little time pulling heavy loads,or really working,in 4wd. with the "straight thru" design of most newer aluminum cases,the gearets and output shafts are plenty strong for 2wd operation. as was mentioned,trucks that do use 4wd experience broken chains from time to time. in this aspect,i can agree some aluminum part time cases may be stronger,specially if the case is used for the most part in 2wd. im sure the nvg 241 does indeed use a beefier output shaft than the d20,so a 1 ton work truck that daily hauls tons and tons of something around all day long,the d20 may or may not last as long as the 241,not real sure on that one.

ur thots? smile.gif

[Stuka]

I agree with scotty. In 2wd I am sure a lot of newer aluminum cases are stronger...the chain is not used and there is just less stress when in 2wd.

But put them in 4wd with a load...and you get what the guy up here gets with his wood cutter. Broken chains....

[UnkleMunky]

A few more thoughts on the issue! tongue.gif

-There are at least a couple NP(NV)241s. One is an "HD" unit, I believe as used in the Hummer and maybe other vehicles. Regular(non-HD) has been used in Grand Cherokees, XJs?, etc. The chain is a LOT heavier duty in the HD units....a notable difference, so that needs to be taken into consideration when mentioning that case!

-By this point in time, many cases being compared(NP208, D20s, etc.) are likely to have been on the road for 10-40 years, and some rebuilt, some abused, some cared for, some not. Heck, look at QTs.....if they are taken care of, one heck of a case, but find an abused one.....sheesh....they can suck. Depends a LOT on the overall condition, care, rebuild, etc. any case has been given over time! It's not always comparing apples to apples in many cases. I don't like QTs myself, but I've seen them in rigs where they rocked! Well cared for units of most decent cases can last a long time!

-Furthermore...I 2nd PCs question about what "light duty" means. To US, we count our FSJs as some of the heavier duty 4x4s out there, compared to CJs, Sammies, Exploders, etc. Yet, our rigs are only 1/2-3/4 ton units, and yet there are trucks up to 1 ton considered "light duty". And many of these used NP208s, NP205s, BW cases(fords), etc. If "light duty" includes 1 ton trucks, maybe that says a lot right there. If it doesn't, then we need to understand what they mean more. As far as I'm aware NP208s WERE put into even 1 ton rigs. But then that was in the '80s when the makers were trying to lighten everything....how many are still holding up in the 1 tons, 3/4 tons, etc.?

-Another thought: The point about the straight-through of the NP208s in 2wd is a good point.....as the chain is usually what goes. Thus, the "weak" point in those cases seems to be the chain. In D20s, etc., maybe it is the yoke, output or non-gear parts, but how often are the gears blowing in D-cases? Even in the TH400/D20 combo, it's not the case the usually explodes, but the adapter. As the saying goes "a chain is only as strong as its weakest link" and in vehicles, it is the weak spot that will show itself first! And, since we're comparing outputs to chains to gears, we're not comparing apples to apples. Maybe a Gear driven case with an output like the NP cases would be an ideal? NP205???? I don't know.....but a thought.

-Finally....as with most things, I can say that it's probably a BIG factor of what shape a case is in that matters most. I intend to put replace the T176/NP208 in the '83 J10 with another of the same for now. I've run a Selectrac on a GW and that was a killer case.....incredible strength. I'm not afraid of the NP chain driven cases for some work I'd use a rig for(even plowing), but I have seen the strenght of a gear driven dana case over the years and THEY are excellent. Yeh, I like the better low range of the NP cases, but I swear by the strength of the Dana20s. I've got a T18 in my 78 and that is an incredible tranny. I've run a few T15s in FSJs, and I haven't been able to kill one yet(even with neglect, long usage, etc.). Those BW cases are killer! The T176 in my '83 isn't as hot, yet I'll live with it with a NP208 behind it for now. T176s lived behind 360s.....and some still are! I think it will handle my 258 fine......just will miss the 6.3:1 1st gear in a T18! smile.gif

Anyway.....good discussion and we probably won't solve anything, but good to open a few more brain cells and fill with some various points to consider. I am glad to hear there is some considerable respect for the 208s, etc. out there...

Take care....

[Jerk]

here's a few more tidbits- I think the term "light duty" is like "suv" "station wagon" and "4wheel drive", ever changing.
I think "light duty" first meant less than 2 ton capacity. what vehicle manufacturers have done with "light" trucks in the last 50 years is kind of interesting. the first chevy and ford "4 wheel Drive" trucks in the '50s were conversion kits by Napco and I can't remember who the other guys were, any way, they were light weight vehicles, as opposed to these days, and had underpowered engines in most cases. now we have things like the Ford F350 Superduty and the Chevy 2500 or 3500 HD. these rigs are HUGE and HEAVY, but haul more weight more efficiently and with greater ease than the old trucks. what does a Chevy HD pickup or a F350 4wd truck use for a t-case? What did the Kaiser M715,(the KING of FSJs in my opinion.)use? is there a difference in what "light duty" means today versus what it meant in the 50s, 60s, 70's, 80's, 90's? certainly. and you have to take into consideration every factor involved as to WHY the case was put in the rig to begin with. its not just, "which case is better?" Thats really a stupid question. what do you have it in, how is it used, how is it maintained? its complicated. What is better, .223 or .308? depends on use, doesn't it?

[ September 11, 2002, 11:29 AM: Message edited by: Matt W ]

[RamJetFSJ]

Todd,
Just noticed on Arizona Drivelines web site that they have SYEs for Chevy 208s. They also say that any slip yoke TC can have a SYE made for it. I dont know if this is exactly what you need, but it should be a start.

208 SYE (http://www.arizonadrivelines.com/slip_yoke_eliminators.htm#Slip%20Yoke%20Eliminator %20(SYE)%20Yoke%20for%20the%20np241,%20np205,%20an d%20np208%20slip%20yoke%20type%20transfer% 20cases)

[River Beast]

Interesting Ben!!!

I see that it just slips on the output shaft and you just drill a hole in the end of the output and bolt it up!! Not bad for $165... I don't know how proven this is though... good find!!!!

[Panther]

Having owned a 208 and D300 rig, I would suggest gear driven case for more serious offroad.
Like scotty said you can't twin stick a 208 like D300 or D20.
I would also add that you can't get more low range either like the 300 and 20.

[RamJetFSJ]

No problem Todd, sorry my link didnt work.. Im having a hard day! smile.gif

Ben

[bvibert]

All this talk about transfer cases is really informative. Keep it up guys, I love learning stuff :D (when its about Jeeps anyway smile.gif )

[Stuka]

Ya twin sticks can be a life saver. I have actually seen guys change the front and rear ranges (front low, rear high etc) to get out of certain areas where the needed different wheel speeds front to rear to get out of stuff.

Do that with a chain drive case smile.gif

[FSJeeper]

Golf ball set up perfectly on a tee! I'll save it for someone else.

[tuck]

Fore!!!
I don't see the golf ball, but please, smash it for us. :D

[FSJeeper]

Originally posted by Stuka:
Ya twin sticks can be a life saver. I have actually seen guys change the front and rear ranges (front low, rear high etc) to get out of certain areas where the needed different wheel speeds front to rear to get out of stuff.

Do that with a chain drive case smile.gif Looks like a perfectly setup golf ball to me! No takers?

[River Beast]

I have golf balls on my D20 Twinstick!!! :D

[Stuka]

FSJeeper: sorry I have no clue what your talking about....I dont get the golf ball tee thing...

[porkchop]

I have golf balls on my sticks as well! That is better than paying $10 a peice for handles.

[WillyPete]

Originally posted by Stuka:
Ya twin sticks can be a life saver. I have actually seen guys change the front and rear ranges (front low, rear high etc) to get out of certain areas where the needed different wheel speeds front to rear to get out of stuff.

Do that with a chain drive case smile.gif *wince* i can just see the driveline tearing itself apart tho if you get too much traction at any given point :eek:

[scotty]

ya,i wouldnt have the b*lls to run my xfer in different ranges! :eek:

[Stuka]

lol scotty...neither would i tongue.gif

but this guy did...he spun his rear tires while trying to grab with the front. It was rather interesting to watch. Not sure what t-case it was..i am guessing a atlas or the like.

[gmcarder2]

Hey guy's can someone explain the twin stick thing to me? I think I get the basic idea but some clarifacation would be cool!
Thanks

[UnkleMunky]

Back to the question of the M715 and M725 xfer case as someone asked a bit ago. I believe I've read it was an NP200 case they used. "maybe" NP201, but VERY low number.....pretty sure it was NP200 though. I "think" it only had about a 2:1 ratio, but again, you had killer axle ratio and a 4 speed with granny 1st to help do work too! Course that meant a ton of torque through the system as well. Oh yes, the xfer case setup in those was DIVORCED, not mated. Not sure if that issue brings any more points to the table, but anyway..that's a bit on the 715/725s as was brought up.

Don't like golf, so you can keep your balls to yourselves guyz! :eek: smile.gif

Take care...

[ September 12, 2002, 02:22 AM: Message edited by: UnkleMunky ]

[scotty]

Originally posted by gmcarder2:
Hey guy's can someone explain the twin stick thing to me? I think I get the basic idea but some clarifacation would be cool!
Thanksin a nustshell,you have multiple levers to control hi/low and 2/4 for more transfer case driving options.

most gear driven cases have a set of high/neutral/low gears for the front,and another set for the rear,so when they are twin sticked,basically each output has its own shifter. that can be shifted independently. i.e.,you can put the rear in high,front in neutral for normal 2wd street drivig. you can put the front in low and the rear in low for a traditional "4lo" or you you can put the rear in low,front in neutral till you need 4wd. this is helpful cause you are not putting unneeded stress on the front drivline and xfer case on high traction surfaces(slickrock,hardpack dirt). it can also mak steering easier with a front automatic locker(detroit or lockright) with the huubs locked,cause in theory the locker is unlocking while it is not recieving torque from the transfer case.

most transfer cases it is even possible for FWD only high or low(rear stck in neutral,front shifted into high or low) which can be very useful for certain situations.

the spicer 18 and some others(sazuki,toyota) are set up alittle differently,and create 4wd by couping the front to the rear set of gears. in these cases you are left with a 2wd/4wd lever,and a high/neutral/low lever. no FWD only is possible.

hope that helped clear it up for ya smile.gif

[gmcarder2]

Thanks scotty! That helps alot.