Transfer case opinions - I gotta make a decision soon.

[B.N.Z.MTNS]

Here's my dilemma. My factory NP 208, T-case is leaking out of the tailshaft at the slip yoke seal. I have replaced the seal twice and it isn't helping. I'm pretty sure the bushing is bad as I do get some vibes on deceleration and sometimes while cruising at highway speeds.

I am either planning on getting this kit from Tom woods along with a new driveshaft


208 Transfer Case GM Design - 32 Spline Output
Uses a modified stock shaft conversion kit provide with: Precision modified main shaft and original equipment speedometer housing which has been re-machined to accept the stock rear out-put seal.

...... or ......

I have a lead on a used NP 241 that I could put a JBC SYE kit on and use a new driveshaft.

Everything I have read says that they are both just as strong as the other and the only real advantage to the 241 is the lower gear ratio. I need to get rid of the slip yoke either way and I already have the 208. If I do the 241 option I will probably be into it for another $200 - $300 over what my 208 conversion would cost.

Will I really notice the difference between 2.61:1 and 2.72:2 ratios? Will 1/10th rotation in my low range ratio be a noticeable difference on the trail? Are there any other advantages on the 241 that would warrant spending another $300 bucks to get my rig trail worthy?

I am trying to get ready for my first Blazer Bash this year and need to get my rig whipped into shape.

Other info on my rig if it helps for input: Stock TBI 350, 700R4, D60 & 14BFF, 4.56 diffs, 38" tires.

 

[82355]

Can a 27 spline NP241 be that hard to find?

Martin

 

[Kay86K5]

When I first bought my K5 it had a stock 208 in it. It ran fine and never leaked a drop, but I ended up finding a 241 (with mechanical speedo so my speedometer still works) for $80 on craigslist. I then purchased a SYE kit from JBConversions and then a Tom Woods CV shaft with a 1350 flange. When I went from the 2.61:1 in the 208 to the 2.72:1 in the 241, I actually did notice a difference. Maybe it was just in my mind, but I felt as though I could feel a difference.

From what I have read, the 241 actually has a stronger case than the 208 (still aluminum, but at least a little stronger). Plus, when I put the SYE kit on, it converts the main shaft from a full 27 spline application to a 32 spline output (still 27 spline input to mate up to the 700r4). When you put the stock mainshaft up against JBConversions SYE shaft, you can tell it is a lot beefier. So you are adding some considerable strength there. Plus, getting rid of the slip yoke was the main reason why I did everything. The peace of mind knowing that if I broke a rear shaft that I could just pull it off and drive off the trail on the front shaft feels really good.

All in all, I highly recommend a 241 with SYE on it. I feel like my gearing is really good with the 3:1 1st gear on the 700r4, to the 2.72:1 in the 241, combined with my 4.56's in my 1 tons spinning 38.5's.

The other thing I was looking at in your pic that you attached...is that truly a slip yoke eliminator?? It looks as though it does replace the tailhousing on the 208 and then has a flange that still "slips" on with a retaining screw. So in theory, yes it does "replace" the slip-yoke, but I wonder how strong that retaining screw is. It seems like the SYE kit from JBConversions is a lot stronger of a design....but I haven't looked at those SYE's for the 208's, so I don't know for sure.

 

[blazinzuk]

I vote 241 if you can go that route.

Reason is basically because the SYE is a stronger setup. While I have no doubt that the kit that Tom Woods sells is a fine kit. It really boils down to a hack and tap style kit. I have done several Jeeps with those and most were fine one, the bolt actually pulled out under a weird circumstance.

The big thing here is cost. If you can't afford the 241 or if the money could be spend other places on the truck than do the 208. If you can swing it then do the 241.

I am not sure that you are going to feel much of a difference in the low range at all

 

[6.2Blazer]

The crawl ratio when going from an NP208 to NP241 is equivalent to going from 3.90 to 4.10 axle gears. I've never personally directly compared the difference between a 208 and 241 in the same truck but did go from 3.73 to 4.10 gears in the same truck and did some fourwheeling and couldn't really feel the difference....those some people may very well be able to notice the difference. One case or the other it is a very small difference so I wouldn't spend much extra time or money going from one to the other.

Regarding the availability of the passenger drop 241 they aren't that common in comparison to the 208 because they were only produced from '89-'91 in K5's and Sub's. This means there are only a small fraction of these 241's out there. However I did just pick one up for $50 a couple of weeks ago for a spare.

 

[Greg Ducato]

If you have the extra coin I vote for the 241, there are other strength advantages to this unit, in particular the planetary, the lower gear is icing on the cake

 

[Kay86K5]

One case or the other it is a very small difference so I wouldn't spend much extra time or money going from one to the other.

Very true. I guess it boils down to how bad do you want to get rid of the slip-yoke and what path you want to take to do it. I personally think the JBConversions SYE kit is the way to go because you replace some key components with beefier parts, and you get some new seals here and there...overall, just stronger. Plus, JBConversions doens't make the same SYE for the 208. The only "SYE" for the 208 that I know of is what was displayed in the first post by B.N.Z.MTNS. But as blazinzuk mentioned, there are some potential drawbacks to that setup. But, if it's what you can afford B.N.Z.MTNS, then do it

 

[Hogback Fabrication]

One other thing that hasn't been mentioned, the 208 SYE doesn't make the transfer case any shorter. The 241 SYE does make the transfer case shorter, which means a longer and flatter rear driveshaft.

 

[K85 Octane]

Ok, I will try to remember all the details but this is a question right up my alley. I drove my truck with the original 208 and TW SYE for a couple outings. Then found an '89 700/241 for a good price and went that route. Nothing else changed. I'm running 38s and 4.88 gears.

I didn't notice the 4L difference
The 241, with standard JB SYE, is only ~3/4" shorter than the TW 208 SYE.

If it were me, I would consider how hard I work the truck. Have I ever had trouble with the 208 or am I just looking for extra strength. Nowadays, 208s are a dime a dozen, so blowing one up wont result in you hunting for another mechanical 241. Also to consider, you are running 38s and 4.56gears. With a 700, that is really high. Save the money using your current 208 and spend some on re-gearing to 4.88 or 5.13. You will feel that more than any difference between transfer case 4L. Also, that rear driveshaft is gunna cost a pretty penny too.

LOL, the output seal will still leak. Both setups did very slightly Oh, and I still have my 208 wrapped up in a trash bag in my garage. It's my spare for trips like Moab.

 

[B.N.Z.MTNS]

Wow, thanks guys, tons of feedback in just a few hours
After a bit more research I have learned that the 241 does have a heavier duty chain than the 208 and supposedly better internal lubrication. If the JBC internal parts are heavier duty than modified 208 parts then my end result would be a beefier 241 instead of just a stock strength, modified 208.

In regards to availability of 241, there are quite a few GM units out there, but finding passenger drop with mechanical speedo is where they become scarce. Since my rig is my daily driver I really do like having my speedometer, even if it isn't exact.

Looks like i'm gonna press on and try to go with the 241 option, I just have to convince my wife that that is the better option regardless of the extra couple hundred bucks it will cost.

 

[ktmoutfront]

I did the 241 when I blew the tail shaft of the 208 out. The picture you show for the 208 is an upgraded version of the "hack & tap" solution. That bolt holding the flange on is a week point. Drive shat hits a rock or a ledge, it tears the bolt out. Saw it happen.

I did not bother with the speedo. GPS reciever is permanently in the truck. So I have an accurate speedo.

 

[sweetk30]

I blew up a 208 on light duty 1 time .

if me go the 241 .

 

[K85 Octane]

to address the "upgraded 241 shaft"
JB told me the shaft is out of a late model 241, factory GM unit
so the shaft isn't anything special over the replaced one
the only thing "beefier" on the new shaft is where it rides inside the dual needle bearings, the shaft is actually larger, so much so that you don't re-install the needle bearings. Was told the newer units don't run them. Made me a little concerned since that shaft and bearings run in 2wd.

 

[80' 427]

My 208 out lived my 10 bolt ring gear.

 

[Kay86K5]

Also to consider, you are running 38s and 4.56gears. With a 700, that is really high. Save the money using your current 208 and spend some on re-gearing to 4.88 or 5.13. You will feel that more than any difference between transfer case 4L. Also, that rear driveshaft is gunna cost a pretty penny too.

I don't feel like my 700r4, 241, 4.56's with 38.5's is a high gear ratio at all. I feel as though it is plenty low. And considering the cost of just purchasing gears sets for both axles (even if he intalled them himself) the cost is pretty high. Then add labor costs if he has someone install them for him. So if you put that money towards this t-case set up with new shafts, you have eliminated multiple weak points throughout the drivetrain, in fact, increased the strength of a lot of them, and still have pleanty low enough overall gear ratio to push 38's.

Not that 4.88's or 5.13's wouldn't be ideal, but if you are looking at cost/benefit associated with what is important for him now, I truly don't think regearing 1 tons would be the right path.

 

[Kay86K5]

to address the "upgraded 241 shaft"
JB told me the shaft is out of a late model 241, factory GM unit
so the shaft isn't anything special over the replaced one
the only thing "beefier" on the new shaft is where it rides inside the dual needle bearings, the shaft is actually larger, so much so that you don't re-install the needle bearings. Was told the newer units don't run them. Made me a little concerned since that shaft and bearings run in 2wd.

It also changes to a 32 spline output. Being someone who installed this exact kit not quite a year ago, I can say that I have zero reserve about this SYE kit.

 

[ktmoutfront]

My 700r4/241/4.56:1 with 35's is too high geared. Would have like to have 4.88:1.

 

[K85 Octane]

Well, since the OP has already made up their mind...

Just saying, after you spend the money on the T-case, you still need the rear driveshaft (241 and 208). So that's extra money on top of everything. And since folks were talking about a lower 4L and I noticed the 4.56 gears, my mind went to the gears, since it would make way more difference than a T-case swap. (a difference in 2wd too, that might not be wanted)

just playing devils advocate here

And Kay86K5: I'll bet you'd have a change of heart if you went steeper gears Looks like your rig is tilted to offroad side more than mine. Also, didn't remember about the 32 spline, not sure if its all that special over a 27, but was just trying to set the record straight about what folks are getting with the JB setup.

 

[Kay86K5]

And Kay86K5: I'll bet you'd have a change of heart if you went steeper gears Looks like your rig is tilted to offroad side more than mine. Also, didn't remember about the 32 spline, not sure if its all that special over a 27, but was just trying to set the record straight about what folks are getting with the JB setup.

I gurantee I would love to have 5.13's!!! Just not in the budget for me or for a lot of poeple I know. That's one of those upgrades I would have to save a while for . And if you looked at the 32 spline next to the 27 spline, you would realize how much more special it really is .

I think all your input is very valid. It's good to always look at both sides of any decision to really get down to what you want and how much you are willing to spend. From my experience, the 241 with JBC SYE kit was a very worthwhile setup (even with the cost of a new shaft in the rear). So if I ever see anyone who is looking at it, I try to be an advocate. But I recognize that not everyone wants to build a rig just like mine.

BTW, K85 Octane, I think your rig is sick

 

[B.N.Z.MTNS]

Thanks again for the input.
Just to address some of your thoughts / concerns.

KTM - I never thought about a drive shaft strike shearing that 3/8" bolt...good point.

K85 - I did read the JBC install instructions and saw it mentioned removing the needle bearings permanently. Sounds like the newer units don't use them at all. It's kind of concerning to me, but makes sense with the larger shaft in place. Anyone with this kit have issues due to not having the needle bearings?

I know that I will have new driveshaft expense no matter which way I go, luckily that is the common denominator in this whole issue and that cost wont change very much regardless of which t-case set up I choose.

Everyone - Believe me, I would love steeper gears in the diffs, however K86 is right. At this point my issues are in the T-case so I will spend what little $$ I have saved up on that first. It will probably be a long time until I get around to gears. When I bought these axles the guy just went through them and did all the seals, bearings and lockers. He rolled his rig with about 700 miles on the fresh axles and decided to part the thing out. I got em and I have put about 3,000 miles on since I have had them...no leaks, no slop. The only thing I plan on changing on them anytime soon is synthetic oil.

If I actually get this 241 in, then I will have my 208 and old driveshaft as a spare if I bust something and get in a bind later. I don't have many spare parts so this may be a good start for me.