SYE and Rear Driveshaft Questions, Hack and Tap, install front driveshaft?

Feorge_Goreman · 06-10-2007, 06:03 PM

Hey all,

I finished puting my RE 3.5" superflex last week nd have been driving around with horrible vibrations. I'm droppng the TC tomorrow, but I know I need to do the whole sye thing and I have a few questions.

1. I know I shouldn't have been driving too much, but something important came up and I've had to use my jeep more than I wished. What would be damaged by me driving it without a TC drop or SYE? What do I need to change out that wouldn't be fixed by adding the SYE and a new rear driveshaft?

2. I think I'm going to do the RE Hack and Tap because I dont really want to go through the trouble of taking the TC out and opening it up and HaT is cheaper. I've heard mixed reviews about HaT, but what brands are good?

3. I've seen many people say to put a driveshaft from the front in the rear, but then again I have herd people say not to do so. My jeep is mostly a DD, but when I do go offroading, it can take a beating. That being said should I get a new driveshaft? What is good to get? If I can replace with a front driveshaft from a yard, what year and models are good? Whay can't I just get another rear driveshaft?

4. I am going to get an alignment because I just installed a lift. Should I hold off on the alignment until I am done with the SYE and driveshaft?

Thanks, you have all been a huge help!

dopod · 06-10-2007, 06:10 PM

Get the alignment whenever you want, the sye won't affect it.

You need a front drive shaft off of an automatic 4.0L xj. Find the newest one you can.

The reason you can't put a rear drive shaft on is because you need the slip yoke in the middle of the drive shaft and a cv joint style shaft. The rear shaft is neither of these.

Get the Rubicon express hack n' tap, a front DS off of a 4.0L auto xj, the adapter flange (spicer part number 211229x), and new u-joints to re-build the junkyard shaft. That's all you need.

I run this setup without problems as a DD/weekend wheeler. I'm not easy on it and it holds up just fine. Total cost should be under 200 USD

Feorge_Goreman · 06-10-2007, 06:12 PM

thanks dopod!

so nothing important will be killed by driving around without a tc drop or sye and driveshaft? it will all be replaced by this new stuff?

Thanks again!

dopod · 06-10-2007, 06:16 PM

Sorry I missed that question...You should get the sye ASAP, and if you can't, throw on a t-case drop so you don't hurt anything.

I wouldn't drive it around much without one of the two. You can do some damage to your t-case if you don't, especially since you said they are horrible vibes.

You can do your own t-case drop with a grinder and a drill. Just get some square tubing and get to it!

NinjaofDoom · 06-10-2007, 07:46 PM

The slip yoke is what is on the rear of the transfercase and the front of the rear drive shaft. this is what you get rid of with a Slip yoke eliminator SYE.

dopod · 06-10-2007, 08:24 PM

Quote:

so nothing important will be killed by driving around without a tc drop or sye and driveshaft? it will all be replaced by this new stuff?

The setup I described is a sye.

**XJK** · 06-10-2007, 08:25 PM

i drove around for a week with my horrible vibes with the 3.5 RE lift and i didnt damage anything. But i would not recommend it at all as it is very harsh on the parts.

I got an inner ear infection because of the compression the vibes were making inside of my jeep

that gives you an idea as to how bad it was.

-Kyle

Ewen91 · 03-12-2009, 02:35 PM

I HAVE to know, I have heard that you can from reading this post and that you cannot in other posts about 5-speed vs auto on the RE hack and Tap and front Driveshaft. I have a 5-speed and I am looking to to the RE hack and Tap w/ front drive shaft. I have heard the driveshaft lenths are not the same. Can I do the RE hack n tap on the 5-speed with front Auto Driveshaft?

firebear · 03-12-2009, 03:59 PM

Yeah, I second that question. Will the RE hack n tap with a XJ automatic front drive shaft work on a 5 speed with the Chry 8.25 and 231?

Thanks.

**xjfever** · 03-12-2009, 04:22 PM

I believe the front shaft from an auto will be too short to work with the 5 speed, and lift. But I'm not sure. If one of you will measure your driveshaft from center of u-joint to center of u-joint with the 5 speed, I'll go measure mine on the auto and we can compare. Rear shaft on my auto is 29.5", front shaft is 31" on my auto. Maybe this will help.

firebear · 03-12-2009, 06:07 PM

From u-joint center to u-joint center on the rear DS it measures out to be about 29.5". From the rear u-joint to the t-case the rear DS measures about 38". It sounds about the same unless I am missing something.

**xjfever** · 03-12-2009, 07:29 PM

It may work for you then. The only reason I could see that it wouldn't would be if the length was different. But apparently it is not. You will lose a few inches of the shaft when you do the hack-n-tap, but my front shaft has a couple more inches left in the cv joint.

firebear · 03-12-2009, 08:03 PM

I wonder what is the actual difference between the two as far as drive shafts go. I guess I will have to find an auto in a parking lot somewhere and roll between the two with a measuring tape until I figure it out.

longtravel1 · 03-12-2009, 08:15 PM

I am doing a Re 5.5 lift this weekend on an 89 auto. I am installing the Sye in the TC. If I understand correctly all I need is a front DS off an auto Xj to make this work.

jk_surgeonfish · 04-24-2009, 11:56 AM

Does anyone know if a Front DS from a TJ will work on rear of XJ? I have 29 spline 8.25 rear.