NP231 upgrades -

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post #1 of 8 Old 03-12-2014, 09:46 PM Thread Starter
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1989 YJ Wrangler 
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NP231 upgrades

so I have a leaky rear main seal. Should I put in a SYE or just replace the rear seal? how much more work is it? If I put in a SYE how much more work is it to put in a wide chain and the 6 gear planetary?

'89 YJ, 4.2L, ax-15, B&M shifter, 1" BL, TJ flares, '99 intake, '91 EFI, 5.0L explorer injectors, GenRight tank & stretch, 35" ProComp Xtreme muds, 52" chevy springs rear, 44044 Ranchos front.....
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post #2 of 8 Old 03-13-2014, 04:41 AM
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no ideao n any of it but don't forget that if you do the sye, you need a new driveshaft.

I don't feel like working on anything at this time so i sold my yj.
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post #3 of 8 Old 03-13-2014, 07:45 AM
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it all depends on if you want to spend $600 sye you could probably do it cheaper than that that's just a ballpark average. Or $5 for a seal
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post #4 of 8 Old 03-13-2014, 02:04 PM
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1990 YJ Wrangler 
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Wide chain and 6 gear planetary...very little extra work if you are doing a real SYE (and not a hack and tap) since you have to open the housing all the way up anyways.

But to change the rear seal you should only need to pull your driveshaft, pop the seal out, and put the new one in. And top off fluid if necessary. Your leaky seal could be the result of not having a SYE though...

Unless you had intentions of doing all of this anyways, I wouldn't let a $5 seal be the impetus for dropping over a grand on your tcase...and getting a new rear driveshaft...and changing your pinion angle to be setup correctly to run with new driveshaft.

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post #5 of 8 Old 03-13-2014, 04:19 PM
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I just had my rear TC seal replaced when it was in for brakes; cost me $80 in addition to the brakes.
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post #6 of 8 Old 03-13-2014, 04:45 PM
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1988 YJ Wrangler 
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If you are referring to the seal in the tailcone at the slip yoke it is easy to change yourself. There are only 3 bolts holding on the tailcone piece. It's a bit of work to pry out the old one and install the new one but its only like $5 for the part and maybe an hour of your time. As far as the SYE 6-pinion and wide chain kit that is entirely up to you. It will cost quite a bit to install those items. for an 89 NP231 it is hard to find a 6-pinion planetary that fits since they changed the gear cut angle in 95. Also you will need to remove the needle bearings from the main shaft to install the SYE.

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post #7 of 8 Old 03-13-2014, 05:57 PM
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Originally Posted by RedRockRed View Post
I just had my rear TC seal replaced when it was in for brakes; cost me $80 in addition to the brakes.
That's y I never go to a shop $80 to change a seal they robbed u man. I do all my own work that way I know what was done and it was done right
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post #8 of 8 Old 03-14-2014, 08:44 AM
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Wide chain kits and 6 pinion planetary can be had on eBAy for a $100 or so, each.
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