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SYE Questions


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So I'm looking to run an SYE in my MJ. Friends have told me to put the CV shaft in and one thing led to another and its basically a do it now or do it 3 months down the road when vibrations beat the crap out of me and i can't take it anymore kinda deal...

 

I'd like to put a hack and tap in, just cause it looks easier and is cheaper. But I am willing to run with the whole shaft replacement kit if need be. (I have this fear of ripping a good t-case apart, I have only replaced the chain in one before and that was scary and frustrating enough)

 

The best deal I could find for the whole shaft was from Offroad Overstock

 

http://www.offroadoverstock.com/store.c ... cfm&cartac tion=none&thisrow=2&action=search&criteria=slip%20 yoke%20eliminator&startrow=1&mystartrow=1&maxrows= 10&cat=&man=&stay=&afid=&searchcat_id=&itemprice=& searchfield=&searchman_id=&boolean=OR&var1=&var2=& var3=&return_product_id=&makeid=&modelid=&modelyea r=

 

Does anyone have info on a great place to buy a hack and tap, I can only find RE kits on the web.

 

I am also going to have to come up with a CV driveshaft. I am running an 8.25 in the rear with whatever the stock yoke for it is... should I be able to find my shaft in a junkyard's bus full of shafts? Can I buy just a CV joint and weld it to the 2wd shaft I have...

 

Any thoughts? Anyone have good or bad ratings on companies?

 

Thanks

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why do you feel like you need an SYE and double cardon rear DS? How much lift are you running. I'm running about 7 inches of lift with not vibes and stock DS. The only reason i would run an SYE would be for the HD Output shaft as the stock output is prone to bending. I would advise against the hackntap. and up for the stronger 32 plines HD ones.

 

If you are having vibes now, then your pinion angle is off. It should be parallel with the angle of the T-case output.

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Yeah, vibrations from what? My driveshaft wasn't even balanced when it was shortened and my ujoint angles are all wrong. No vibes at all from it. All I did was replace the U-joints. (U-joints don't like it when you change their operating angles)

 

Has anyone here had vibes from a rear MJ driveshaft?

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The only reason I could see for runnin an SYE on a MJ is for the feature of being able to remove the rear DS without loosing fluids, Just in case you whack the rear DS while wheeling ( had this happen on a trip to tellico on an XJ )

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Has anyone here had vibes from a rear MJ driveshaft?

 

 

Mine did stock. Not exactly sure why. Maybe the joints were bad, maybe it was seriously out of balance.

 

 

 

However, when I totalled my TW double cardon shaft, it didn't vibe. Not until I ripped the tranny mount in two.

 

 

Oh, if you can change a tcase chain, you can install a HD SYE.

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See, the beauty of this whole thing is that I havent welded my spring perches yet, its all just bolted together. So I'll have no problem getting my pinion back down to paralell and burning those suckers in. I have my new U-joints and the old 2wd driveshaft to hack up. I originally planned to just shorten the driveshaft and then a bunch of people warned me of the vibrations. All I needed to hear from you guys is that they won't be a problem and I'm sold. It made sense to me anyway from the get go because the driveshaft is so much longer to begin with than an XJ's.

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If this is a strret rig, or one that see's lots of street duty, I owuld definately have the driveshatf proffesionally done by a loocal shop. As for the SYE...There aqre only a few advantages... the first one being the increased strength. Also if you decide to chop your rig like I did.. sye is a must

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But you can do it later then...

 

 

 

Worst that'll happen is he'll break the stock 231 output shaft (do-able, I know a couple) or wrap up his driveshaft and have to use some duct tape abbomination to stop the tcase from going dry. That or if the shaft is too short it will pull out of the slip yoke...

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I'm running a SOA in the rear, about 6.5" of lift, no vibes with no SYE.

 

On the other hand, I've installed about a half dozen PORC SYE's and they're decent kits. A TJ/XJ/MJ front CV driveshaft, when cut to length, will bolt right into the rear with a SYE.

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I'm running a SOA in the rear, about 6.5" of lift, no vibes with no SYE.

 

On the other hand, I've installed about a half dozen PORC SYE's and they're decent kits. A TJ/XJ/MJ front CV driveshaft, when cut to length, will bolt right into the rear with a SYE.

 

 

In an XJ maybe... For a MJ you'd have to get it retubed to be long enough.

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500 MJ: i wouldnt fear rippin down a t-case to do a SYE its a pretty easy install, me and my brother did an AA kit on a 231 not 2 weeks ago, VERY simple, only ran into 2 problems, one was not having snapring plyers, and 2 was the pinion nut must be removed and it was torqued to 300+ ft lbs from 17 years of use, so if you have snapring plyers and a shop thatll blast off that pinion nut for you i wouldnt fear.

 

however a hackntap kit ive heard bad things about, cause of the weakness of the stock shaft.

 

good luck-nick

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however a hackntap kit ive heard bad things about, cause of the weakness of the stock shaft.

Tell me more about the weakness of the stock mainshaft? Ever see one break?

 

 

 

Yup. About 5. It happens. The shaft is just too itty bitty and it goes pop. But the guys who I saw break them weren't being easy on them...

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I've repaired one that broke clean in half where the speedo gear meshes. I've bashed on my H&T with no problems.

 

Looking back, and seeing how cheap HD SYE's are now, it makes sense to get the HD shaft. Not to mention you have to spend $40-$60 on a CV flange to bolt a CV driveshaft up to the RE H&T flange.

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kind of off topic but my mj only has a spring over and coil spacers and when i pulled my motor out the rear driveshaft fell out, its stock length just wondering if this was normal?i was also planning on doin a sye kit once i added a set of rusty's 4 inch leaves to the spring over but apparently this isn't necessary would just a lengthened cv style shaft be suficent for my lift

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what would you replace it with? D300?

 

Personally I went straight to the Atlas II. Wish I'd gotten the higher ratio - but the guys I wheel with didn't have much crawl beyond stock I went with the 3.8 because I needed to keep up.

 

My thought was not buying an SYE is like a $300 coupon...

 

My only regret besides going with the 3.8 is that the input is for an AX5 (21 spline I think?) and AX15s are 23 so it wouldn't fit on my TJ. It's one of the reasons I put my old AX5 behind the 2.5L instead of buying an AX15 to do a 4.0L swap on the MJ -- now the $300ish kit to change the input splines is too much.

 

Don't quote me on the spline counts. brainbang.gif

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When I did my SYE I also had to cut one of ... no biggie.. just a bit of a PITA... As for wethere or not I would do it.. or put a different t-case in.. To set up a d300 you need a flip kit, and an adpater... if you have a 21 spline tranny (expensive NOVAl sell one with adapter, and input shaft for 368), then you figure 4 to 1 kit (500-600 from JB conversions) Did I mention new seal kit.. (I think I seen them for 75)... The d300 is not the best choice.. if you don't all ready have one, or if you plan on keeping drivers side drop...

 

 

Atlas II they are kinda pricey, but a new 4 spd one can be had for aropund 2500-2700

 

 

Then you can go the route of np 203 and np205 doubler.. if you have both cases.. still looking at 700-1000 for everything...

 

Best option in my opinion is the 4 to 1 terra low kit.. les work, and 4 to 1

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what would you replace it with? D300?

 

 

Oh, now that's a can of worms!

 

 

Any of (or possibly multiples of) the D20, D300, NP203, NP205, NP229 (easy swap), dual toyotas. And maybe a klune V. Or that madrooster setup to run the NP231 planetaries and a D300 (or a D20, I think) behind it.

 

 

I don't like the Terralow kit for the NP231 because it wasn't ever ment to be a HD tcase, so you'll just run into more trouble with the extra torque.

 

 

Money Money Money!

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