Steering Box "Upgrade"

[gogmorgo]

That's all well and good, but the MJ/XJ/ZJ doesn't use a rack and pinion... it's a recirculating ball gearbox. Completely different animal.

The steering column turns the worm shaft deal, centre-right in the photo below, corkscrew looking deal. It's got all the same pitch because you would have to change the diameter of the ball bearings on the fly (good luck) to get any variation in ratio at this step. To the left of the worm shaft left is the shaft that turns the pitman arm. There's what, three teeth on it that are relevant to steering ratio, and you can't exactly change pitch in a symmetrical system that only uses three teeth. The balls in the worm shaft push the "rack" (for lack of a better word), right above the worm shaft in the photo below, which as you can see has very few teeth and even gear pitch as well.

 

Here's a close-up of the "rack", everything's the same there:

And here's the engagement of the gears:

 

As you can see there's no variation in anything there. It's a fixed ratio box, for sure.

That's not to say there won't be a variation in effective ratio due to steering geometry, i.e. the pitman arm moves through an arc and therefore will have faster travel on-centre than it will towards the edge of its travel. But the box itself is a fixed ratio.

Image source: http://www.jeepforum.com/forum/f13/how-rebuild-your-saginaw-zj-steering-gear-1287958/

[HOrnbrod]

That's all well and good, but the MJ/XJ/ZJ doesn't use a rack and pinion...

Must have been referring to KJ's.  :yes:

[mikekaz1]

Yeah. I'm thoroughly confused as to what relevant point Tex06 is getting at....

[Eagle]

That's all well and good, but the MJ/XJ/ZJ doesn't use a rack and pinion... it's a recirculating ball gearbox. Completely different animal.

The steering column turns the worm shaft deal, centre-right in the photo below, corkscrew looking deal. It's got all the same pitch because you would have to change the diameter of the ball bearings on the fly (good luck) to get any variation in ratio at this step. To the left of the worm shaft left is the shaft that turns the pitman arm. There's what, three teeth on it that are relevant to steering ratio, and you can't exactly change pitch in a symmetrical system that only uses three teeth. The balls in the worm shaft push the "rack" (for lack of a better word), right above the worm shaft in the photo below, which as you can see has very few teeth and even gear pitch as well.

 

As you can see there's no variation in anything there. It's a fixed ratio box, for sure.

That's not to say there won't be a variation in effective ratio due to steering geometry, i.e. the pitman arm moves through an arc and therefore will have faster travel on-centre than it will towards the edge of its travel. But the box itself is a fixed ratio.

Variable ratio is not impossible with a tradition worm-and-sector steering box. Generous Motors had them back in the early 70s. My mother had a 1970 AMC wagon with a Saginaw variable ratio box. The theory behind it is that when the wheels are straight, X amount of lateral movement of the drag link results in Y degrees of wheel turn. However, due to geometry, as the wheels move farther off center, that same X amount of lateral movement in the drag link and tie rod doesn't generate as much angular displacement of the road wheels. So they came up with variable ration boxes as a way to (supposedly) make the steering more uniform.

 

Personally, I hated it. The ratio varied from about 17:1 at the center to around 13:1 at full lock. It was too slow to react at highway speeds, making evasive maneuvers less effective. I much prefer fixed ratio. That's what I've been driving for 60 years, so I guess I'm sort of set in my ways.

 

Back to the reason for this post: Not only is variable ratio possible in a standard Saginaw steering box ... they exist.

[mikekaz1]

But the initial counter point is the MJ boxes are all 14:1 fixed ratio. So swapping to a ZJ/Durango box to get rid of "variable" steering is false

[Tex06]

Yeah. I'm thoroughly confused as to what relevant point Tex06 is getting at....

The point I'm getting at I reckon is no one seems to have dissembled and measured an MJ steering box to tell if it is indeed a variable ratio Saginaw box. According to multiple forums so far I've read that XJs (and by I have assumed this to be true for MJs) are either all variable, all fixed, or came with both.

 

I haven't been able to find anything concrete either way, but I can tell you my MJ steers like my '86 Chevy Truck which DOES have a variable ratio Saginaw steering box in it. Very much a one finger driver, lol.

 

I'm going to try and get access to the water jet table in the next few weeks and slice my MJ box in half after I rebuild and install the jy Saginaw 800 I pulled from a 96 Grand Cherokee. If that works out, I'll post up the pics of what I find. Should be pretty easy to tell on the sector gear or worm gear if it's variable or not.

 

Sent from atop the porcelain throne.

[Eagle]

The point I'm getting at I reckon is no one seems to have dissembled and measured an MJ steering box to tell if it is indeed a variable ratio Saginaw box. According to multiple forums so far I've read that XJs (and by I have assumed this to be true for MJs) are either all variable, all fixed, or came with both.

 

I haven't been able to find anything concrete either way,

I've given you something concrete. The factory service manuals from 1986 through 2001 ALL say fixed ratio steering box. The factory parts manuals list variable ratios only for models other than the XJ and MJ, and then mostly for export only. I don't know about you, but I'll trust the factory before I'll trust something I found on the Internet.

[DirtyComanche]

I've seen XJ/MJ boxes blown apart and I don't see how they could be variable.  I also have seen no reason to believe they are based on all the stupid things I have done trying to make steering work.

 

I also don't feel they drive wrong.  Anything you're noticing while driving them is the result of the pitman arm being a different length than the steering arms, but the effect is fairly minimal.

 

The factory didn't always get it wrong.

[Eagle]

Depending on what the OP is accustomed to driving, it may just be the amount of boost that's fooling him. AMC was always famous/infamous/notorious for using too much boost in their power steering, resulting in zero road feel. Chrysler eventually corrected that in the XJs, but I don't know when. I can tell you that, although my 1988 XJ and my 2000 XJ both have power steering and both have 14:1 boxes, the steering "feel" is completely different. As different as night and day.

[DirtyComanche]

Depending on what the OP is accustomed to driving, it may just be the amount of boost that's fooling him. AMC was always famous/infamous/notorious for using too much boost in their power steering, resulting in zero road feel. Chrysler eventually corrected that in the XJs, but I don't know when. I can tell you that, although my 1988 XJ and my 2000 XJ both have power steering and both have 14:1 boxes, the steering "feel" is completely different. As different as night and day.

 

Chrysler then went the other way with that.  My JK has damn near zero feel to it.  Drive it, get used to it, learn to love it.

 

But yes, the early XJ/MJs have very light steering if everything is working correctly.  That's a big if though.

[HOrnbrod]

The factory XJ and MJ box is 14:1 and 3-1/2 turns lock-to-lock. The 12.7:1 ZJ box is 3 turns lock-to-lock.

 

I have a ZJ box in the 2001 XJ, and the factory box in my wife's 2000 XJ. The only time/place I notice any difference is when backing up and turning 90 degrees in the driveway. On the road I don't notice any difference whatsoever.

Eagle, the steering gear you installed didn't have the tag showing the alpha code, so who knows what box you have if you can't ID it? I do have a 95 ZJ box with the correct alpha code tag ID'ing it as the 12.7 ratio installed (the codes vary throughout the ZJ 93-98 years). There's a very obvious difference on the road, like immediately obvious. If you don't notice it you probably don't have the right box installed.

 

Dirty's comment above regarding "boost" may also have something to do with my results. I also changed out the stock pump with one from an 04 Wrangler, also a Saginaw TC series pump, at the same time to get the late model brackets for the 99 intake manifold install. I don't have the specs as far as pressure differences between the two so ?? This could explain why my results were much better than what you claim.

[Eagle]

Eagle, the steering gear you installed didn't have the tag showing the alpha code, so who knows what box you have if you can't ID it? I do have a 95 ZJ box with the correct alpha code tag ID'ing it as the 12.7 ratio installed (the codes vary throughout the ZJ 93-98 years). There's a very obvious difference on the road, like immediately obvious. If you don't notice it you probably don't have the right box installed.

The junkyard box I put into the '01 is 3 turns lock-to-lock. The '88 XJ, the MJs, and the '00 XJs are all 3-1/2 turns. That tells me the junkyard box is 12.7:1 ratio.

[DirtyComanche]

Dirty's comment above regarding "boost" may also have something to do with my results. I also changed out the stock pump with one from an 04 Wrangler, also a Saginaw TC series pump, at the same time to get the late model brackets for the 99 intake manifold install. I don't have the specs as far as pressure differences between the two so ?? This could explain why my results were much better than what you claim.

 

 

That's more Eagle's comment. :D

 

But here's what I will tell you, all the early XJ/MJs (with 4.0L engines) used the highest pressure TC style steering pump that was available.  They can also be turned up more safely...  However, IF you install a reman pump you may get ANY TC pump back, as they are all 'the same' in the opinion of the people who overhaul them.  Also, many of the remans do NOT bench test them for pressure output, or if they do they have a very wide acceptable range.  The factory new pumps had the regulators adjusted to +/-25PSI of spec, IIRC.  The remans are obviously nowhere near this level of quality.

 

I believe the TJ pumps were also the best of the TC pumps.  If you swapped a worn out, or bad reman, for a good factory pump I KNOW you would see a difference, as it could easily be as much as 30% more pressure from the good pump VS the marginal one.

 

4cyl TJ pumps also came with a remote reservoir, if somebody needs that to address packaging issues.  It's somewhat less than ideal with a 3/8 supply line, but it work for factory type applications.

 

The WJ pump with the factory hydraulic fan is even more hot-rodded than the other Jeep ones, they ported it for high flow and installed a different reservoir to reduce cavitation issues.  Pressure remains the same though.  Now, if you go and buy a reman version of these, you might just get a junk TC pump with the WJ fittings on it, which actually would be really far from ideal as it would probably cavitate in any application.

[big66440]

 

Unless it was free, and even still, the 1/2 a turn savings doesnt seem worth the hassle of the swap.

I agree. The '01 steering box had been trashed by a previous owner and couldn't be adjusted, so I had to replace it anyway. If I had it to do over, I'd go to AGR Steering and buy a 10:1 box. (Which would NOT be good for large tires and rock crawling.)

 

That 10:1 box sounds interesting, do you have a part number?

[HOrnbrod]

A 10:1 ratio box would be ridiculously quick on an MJ and super twitchy. That's a common NASCAR steering ratio depending on the track and on a relatively sloppy MJ steering system it would be flat out dangerous on the street. I'd consider going down to a 12.1:1 box for the street, but no lower. Even the steering gear manufacturers don't recommend it.

[gogmorgo]

After haven driven with 1 turn of the wheel lock-to-lock, it's kinda addictive. You get used to the quicker ratio pretty quickly. At the same time you shouldn't be driving in such a way to properly take advantage of the quicker ratio on the street, but not having to turn the wheel as far is definitely a good thing, in my mind at least. But I guess quick-responding agile vehicles aren't for everyone?

[Tex06]

Twitchy steering is great in my Fiero as it spends most of its life on the track. I think I have 1.5-1.75 turns lock to lock but the center of gravity is low enough to not worry about stability issues.

 

My 4x4s I like responsive, but streetable for both myself and my girlfriend. It's all about personal preference and your driving style.

 

Sent from atop the porcelain throne.