Gearbox

[ahmincha]

Hi all, I have searched all over and cannot find my answer. 

What year Dakota or Durango steering gearbox or zj is bolt in? 

[strictlyxjs]

Any year zj will bolt up however the pitmam ar is diferent. Not sure on the dakota boxes i think like a 99 durango with thenplow package is the one people are usually after.

[Minuit]

I wouldn't know about the Durango box, but I just finished swapping a ZJ box into my '91 and I strongly recommend it for any street-driven application.

 

Any ZJ (that's '93 through '98 Grand Cherokees to normal people) gearbox will fit, and for a street driven truck it gives a very noticeable improvement in steering response thanks to the faster gear ratio (12.7:1 as opposed to the MJ's 14:1). You'll need to swap your original Pitman arm onto the ZJ gearbox (this can be a job in itself), but other than that it's a direct fit. Don't buy a remanned ZJ box, as there's no guarantee that the faster gears will be in it still. You want an original un-rebuilt gearbox that came straight out of a ZJ before you got it.

 

If you are wheeling the truck, you wouldn't want a ZJ box. Because of the faster gear ratio, steering effort will be higher and it is no stronger than the original box. If the truck is driven on the street though, I can wholeheartedly recommend it. After putting a few miles on my 91 with the ZJ box, I'll be getting one for my other truck very soon. Swapping a steering box is a crappy job to do alone, but the improvement is worth it. Replacing the intermediate shaft is easy to do at that point if yours is worn out.

 

However - adjust the new ZJ box before you put it in! A ZJ box with some miles on it is likely to be just as loose as your original. It must be adjusted outside of the vehicle and there is a specific procedure outlined in the factory service manual that almost NOBODY follows, which is a potentially dangerous mistake and can easily result in the steering box being ruined. You'll need an inch-pound beam style torque wrench at the very least, and you may want to have a spanner wrench to loosen and re-tighten the input shaft lock nut. I just used two pin punches and a screwdriver though.

[75sv1]

The Dakota box is a bit wider. You would need an aftermarket steering box plate. The snow plow version has a side port for the hydraulic ram to angle the snow plow. I think some use it to add hydraulic steering. I think around 98-00. There are some internal mods to get better lock to lock steering. Stock I believe you will lose turn radius. I did nab one and rebuilt it. As Minuit said, you do need to adjust with an in-lb torque wrench. 

[WahooSteeler]

12 hours ago, Minuit said:

Any ZJ (that's '93 through '98 Grand Cherokees to normal people) gearbox will fit, and for a street driven truck it gives a very noticeable improvement in steering response thanks to the faster gear ratio (12.7:1 as opposed to the MJ's 14:1). You'll need to swap your original Pitman arm onto the ZJ gearbox (this can be a job in itself), but other than that it's a direct fit. Don't buy a remanned ZJ box, as there's no guarantee that the faster gears will be in it still. You want an original un-rebuilt gearbox that came straight out of a ZJ before you got it.

 

Minuit, it sounds like your speaking from experience, did ZJ boxes come with different gear ratios? If not, it would seem (to me at least) very unusual for a reputable reman company to change the ratio. If that is true then if I buy a reman'd MJ box I might end up with ZJ ratios? Asking because I think I may be in the market for a box soon and would consider a ZJ unit. I'd rather buy a quality reman unit than a used one with no idea of the condition. Then I'd have to get that rebuilt or replaced if it fails and I'm back at square one. 

[Minuit]

37 minutes ago, WahooSteeler said:

 

Minuit, it sounds like your speaking from experience, did ZJ boxes come with different gear ratios? If not, it would seem (to me at least) very unusual for a reputable reman company to change the ratio. If that is true then if I buy a reman'd MJ box I might end up with ZJ ratios? Asking because I think I may be in the market for a box soon and would consider a ZJ unit. I'd rather buy a quality reman unit than a used one with no idea of the condition. Then I'd have to get that rebuilt or replaced if it fails and I'm back at square one. 

All ZJ boxes have the 12.7:1 ratio. Not all XJ boxes have the 14:1. I think there was a slower power steering ratio offered as part of an offroad package at one point, and I want to say the manual steering boxes have an 18:1 or maybe even slower than that. The slower power steering boxes are probably quite rare at this point.

 

You'll see remanufactured gearboxes under the same part number listed for several different Jeep models - from what I can tell, most if not all rebuilders have them lumped together. For example, O'Reilly Auto Parts lists the same part number, Masterpro 503-0122 for both a '91 MJ and a '93 ZJ. The only real difference between the MJ and ZJ boxes is the gear ratio so they are "technically correct" in giving them the same number, but if I wanted the quicker ratio and still ended up with a slow @$$ 14:1 box after asking for a ZJ box, I'd be very disappointed. So you might end up with anything if you buy a remanned box. I'm sure some lucky soul ended up with a 12.7:1 box when he paid for a 14:1 box, but you never know what you'll get.

 

If you're set on a rebuilt box, test it on the parts counter. I believe the 12.7:1 box is about 3 turns from lock to lock outside of the vehicle. The 14:1 box is about 3.5. My memory might not be correct on those numbers, but the ZJ box is less for sure.

 

Not only that, but the reviews I've seen on the parts store reman boxes have not exactly been positive. The ZJ box I adjusted for my '91 by the FSM procedure is as tight as you're gonna get with a recirculating ball system. According to the reviews on the reman boxes, they can be as sloppy as a high-mileage original right out of the gate. I would expect better from a dedicated steering box rebuilder, but those "boutique" rebuilt boxes are damn expensive!

 

On my very first test drive, I noticed a major difference in quickness by the time I'd backed out of the driveway. You'll know it when you drive it. That was confirmed when I took my '89 (with original, kinda loose 14:1 box) on a dump run about a week after doing the swap and I was shocked at how slow and sloppy the steering felt compared to the '91 - before the swap, they were roughly even, with the '91 having somewhat tighter response than the '89. I'll be getting and adjusting another ZJ box for the '89 pretty soon.

[WahooSteeler]

9 minutes ago, Minuit said:

You'll see remanufactured gearboxes under the same part number listed for several different Jeep models - from what I can tell, most if not all rebuilders have them lumped together. For example, O'Reilly Auto Parts lists the same part number, Masterpro 503-0122 for both a '91 MJ and a '93 ZJ. The only real difference between the MJ and ZJ boxes is the gear ratio so they are "technically correct" in giving them the same number, but if I wanted the quicker ratio and still ended up with a slow @$$ 14:1 box after asking for a ZJ box, I'd be very disappointed. So you might end up with anything if you buy a remanned box. I'm sure some lucky soul ended up with a 12.7:1 box when he paid for a 14:1 box, but you never know what you'll get.

 

Good points, and as somewhat of a confirmation to that, I was looking at the AC Delco or Lares units on RockAuto. The ACD unit specs show 3 turns lock to lock and, yes, it is the same P/N for the MJ/XJ/ZJ. Thanks for the info 

[ahmincha]

Thanks for all the replies. 

Also thanks for the move to the correct section 

[EvilMJ]

Good info!

[omega_rugal]

7 hours ago, 75sv1 said:

The snow plow version has a side port for the hydraulic ram to angle the snow plow. I think some use it to add hydraulic steering.

 

what?

[Eagle]

1 hour ago, Minuit said:

If you're set on a rebuilt box, test it on the parts counter. I believe the 12.7:1 box is about 3 turns from lock to lock outside of the vehicle. The 14:1 box is about 3.5. My memory might not be correct on those numbers, but the ZJ box is less for sure.

 

 

Correct on both numbers.

 

Having run a ZJ box in a 2001 Cherokee, at this point if I had an MJ that needed a steering box I would go to AGR Steering and buy one with a 10:1 ratio. Hornbrod disagreed with me -- he thought that was too fast -- but IMHO the longer wheelbase of the MJs (especially the LWB models) would make it feel about like the 12.7:1 box in an XJ.

[75sv1]

48 minutes ago, omega_rugal said:

 

what?

http://www.nwjeepn.com/SteeringGear.html

I do not know how accurate the info is. I did search a bit before I grabbed a gearbox at the PnP.  If you have any info otherwise, please post. 

 

Edit: I did read another post on this box. Some info has it as just a different ratio. ???  I do see some rebuilders adding in ports to them. 

[schardein]

Now I'm interested in a ZJ box.  Any tips for pulling one, from those who've done it?

 

I assume line wrenches for the P/S hoses, cotter pin and castle nut big hammer for drag link, remove steering intermediate shaft (not familiar with attachment method of ZJs), remove mounting bolts.  

 

Did I miss anything?  Tips?  I'd remove the pitman arm after I got it home on a bench... unless they are going to charge extra for it.

[DirtyComanche]

22 minutes ago, schardein said:

Now I'm interested in a ZJ box.  Any tips for pulling one, from those who've done it?

 

I assume line wrenches for the P/S hoses, cotter pin and castle nut big hammer for drag link, remove steering intermediate shaft (not familiar with attachment method of ZJs), remove mounting bolts.  

 

Did I miss anything?  Tips?  I'd remove the pitman arm after I got it home on a bench... unless they are going to charge extra for it.

 

If it's from a wrecker that doesn't totally care, I'd just cut the hoses.  Easier that fighting with them.  Buying used hoses is like buying used underwear anyways, so most wreckers will not care at all if you snip them.  If they're real seized in there you will probably round them (even with flare wrenches) before getting them out anyways.  Steering shaft attaches the same way, take the clamp bolt out and spread it with a screwdriver if needed.  Maybe take a pickle fork for extra mangling action on the drag link end.  The pitman arm normally goes with the box when a wrecker sells it.

[Minuit]

1 hour ago, schardein said:

Now I'm interested in a ZJ box.  Any tips for pulling one, from those who've done it?

 

I assume line wrenches for the P/S hoses, cotter pin and castle nut big hammer for drag link, remove steering intermediate shaft (not familiar with attachment method of ZJs), remove mounting bolts.  

 

Did I miss anything?  Tips?  I'd remove the pitman arm after I got it home on a bench... unless they are going to charge extra for it.

I cheated and bought a pre-pulled one for $85, unfortunately with the ZJ pitman arm still attached. Putting it in my truck sucked enough that I feel justified in paying someone else to pull the ZJ unit. I'd hate to do it in the muddy nastiness that junkyards in TN are this time of year.

 

Pull the drag link first. On my MJ, I used an OTC tie rod remover to non-destructively remove the TRE from the MJ pitman arm.

 

In the junkyard I'd go ahead and pop the ZJ pitman arm off while the box is attached to the ZJ - you won't be needing it and my junkyards charge extra for a box with the pitman arm. I don't remember what size the pitman arm nut was, but think axle nut socket. On both the MJ and ZJ boxes, the nut spun right off with no trouble.

 

Next up, pitman arm puller time. You'll want the biggest pitman arm puller you can find. I removed the MJ pitman arm with the box still installed in the truck. My 450 ft-lb Milwaukee impact on the forcing screw wouldn't even budge it. I ended up needing to bust out the 3 foot cheater pipe on a breaker bar and a 4lb sledgehammer to get the ZJ pitman arm off. I got the pitman arm puller REALLY tight and then smacked the pitman arm as hard as I could with the hammer. A few repetitions of that got the pitman arm off. The steering shaft attachment at the steering box is just a pinch bolt. I think you have to take it out all the way. You might want to spread the attachment knuckle. I didn't need to on my MJ.

 

Remove all the $#!& that'll be in the way of getting the power steering hose fittings off. In my MJ, I went ahead and pulled off the top radiator support and aux fan. Access still won't be good, but it was workable. Crowsfoot wrenches might be a help here. I didn't have any in the right size, so I had to fight with it 1/16 of a turn at a time.

 

The return line on my MJ got seized to the fitting. The fitting came loose just fine, just with the line stuck to it. An Autozone nearby had a new return line assembly in stock - you may want to have new pressure and return lines ready just in case. Good time to replace them anyway.

 

Oh, yeah - O-RINGS! I used various sizes of HNBR o-rings meant for A/C service. They're oil resistant and I have tons of them thanks to working on HVAC systems. Have a large assortment of o-rings ready. Harbor freight sells a couple of good assortments that are handy. My rule of thumb is that o-rings on A/C, hydraulic, and other types of fittings are single use, and I always replace them when disconnecting them.

 

Once the drag link, hose fittings, and intermediate shaft are loose, the 3 bolts in the driver side wheelwell can come out and the steering box will be free. The MJ steering shaft does not collapse easily, so you'll have to worm it off with the steering box loose, or at least I did. I don't know if the ZJ steering shaft collapses easily. If it does, that'll make removal a little easier.

 

There is not a better time to replace the intermediate shaft than now. They're available new for about 100 bucks. Mine had a very small amount of play in it, so I replaced it.

 

Now is the time to adjust the box. I followed the '93 FSM's procedure for adjusting. I ended up with about 10 in-lb of drag over-center. The FSM specifies 18 in-lb as the maximum. I suspect the ZJ box would've been loose had I just put it in without adjusting it, as it had absolutely no drag over-center before the adjustment.

 

Installation is the reverse of removal. The steering box weighs 30 pounds without the pitman arm. It is not fun to hoist above your head with one hand while lining up the intermediate shaft, the steering box spacer, and the first of the three bolts with the other hand. This was the most unfunnest part. If you have any way to rig the steering box so you don't have to hold it up, do it. A transmission jack might even do it. I was working alone and had no way of holding the box up, so brute force and ignorance it was. The intermediate shaft is indexed to both the column and gearbox, and they all must be lined up correctly for it to fit.

 

Once the box is securely mounted (make sure to hook up the intermediate shaft BEFORE putting a bolt in), hook the pressure and return lines back up, install the MJ pitman arm, and reconnect the drag link. Next up is to bleed the system. This took me two days of on-and-off work before I had no cavitation or foaming of the fluid.

 

Bleeding the power steering system was for me the second most unfunnest part. The factory procedure is to jack the truck up and turn the wheel back and forth WITHOUT touching the stops dozens of times without starting the engine. I eventually got it to bleed by loosening the return hose on the back of the P/S reservoir and draining a little bit of fluid out. Don't ask me how that helped, but it did. I had some power steering pump noise before the steering box swap, and after flushing it with new fluid, it seems a little quieter. Knock on wood.

 

Fun job. I'll be doing it again to my 89 pretty soon.

[schardein]

29 minutes ago, DirtyComanche said:

If it's from a wrecker...

 

4 minutes ago, Minuit said:

I cheated...

 

Thanks for the advice guys, that helps.  I've recently done steering box work on two of my CJs, so familiar with overall procedure.  I have several of the cheap harbor freight pitman arm pullers, broke one trying to get the arm off an old CJ box.  I think it's 50/50 they will charge me for the arm around here, so I'll go prepared to pull it.

 

 

[cruiser54]

Uh-oh, on my 4" lifted MJ, I used the ZJ pitman arm.........

[1987Comanche]

I just pulled another ZJ box for my MJ.  The AutoZone 27022 puller works well to remove the drag link from the Pitman arm.  Drag link nut is 3/4", Box to frame bolts are 5/8", fluid inlet & return lines are 18MM, and the steering shaft pinch bolt is 13mm.  The AutoZone HD pitman arm puller works to pull the Pitman arm from the box but you need to replace the bolts that hold the puller arms together with grade 5 or grade 8.  The bolts with the tool stretch & bend easily.

  I took a tubing cutter so I could cut the pressure line and connect pressure & return lines in the junkyard.  Keeps the ports clean and keeps the mess to a minimum.

[schardein]

44 minutes ago, cruiser54 said:

Uh-oh, on my 4" lifted MJ, I used the ZJ pitman arm.........

google research shows ZJ pitman provides 3/4"-1" drop from stock XJ/MJ.

[schardein]

3 minutes ago, 1987Comanche said:

I just pulled another ZJ box ...  

  I took a tubing cutter so I could cut the pressure line and connect pressure & return lines in the junkyard.  Keeps the ports clean and keeps the mess to a minimum.

 

Thanks for those details!  

I thought pressure and return lines used different wrench sizes?  At least in every case I can recall working on P/S systems recently.

I have big bag of these to keep dirt out and fluid in when pulling, transporting and storing steering gears, pumps, or hydroboost units.

[1987Comanche]

If the lines are OEM they're both 18MM.  I've encountered aftermarket lines that are 18MM feed and 3/4" return. 

[schardein]

10 minutes ago, 1987Comanche said:

If the lines are OEM they're both 18MM.  I've encountered aftermarket lines that are 18MM feed and 3/4" return. 

The 18mm-3/4" are how they are on my LS engine/hydroboost unit/CJ steering gear in my CJ-7.  The HB has pressure in & out, in addition to a return.

I like the return hose to pressure line trick, even though I have the plugs.

 

Edit:  Looks like you also got the pump.  Any difference/advantage to ZJ pump?

[1987Comanche]

ZJ pumps through '95 are a direct interchange for my MJ, which is why I picked it up.  No advantages other than the fact that it works and the Mexico reman unit I got at the parts store didn't. It sounded like marbles in a coffee grinder.

[Minuit]

The fittings on the steering box were both 18mm for me.

[High2by]

I just got a box from a '98 ZJ and my plan is to have it rebuilt for the MJ. Both lines on it were 18MM.