Bought another XJ - suspension question

[EvaB99XJ]

I’ve got something that I haven’t been able to figure out and it’s bugging me. I’m hoping that the sleuths here can help.

I have a 2 wheel drive 1999 Cherokee sport that doesn’t have trailer towing or anything else suspension-wise on it.

I just picked up another XJ - a clean 4 wheel drive sport that’s also pretty vanilla as far as the suspension goes - no upcountry or anything like that.

Here’s the mystery - the “new” XJ rides MUCH smoother than the old one does - the old one will rattle your teeth out when going over bumps, the new one - not so much.

Out of curiosity I’ve been trying to figure out why this is. I’ve been researching factory spring options and not finding much. I decoded the VINs and didn’t see anything except some cryptic sales codes for the springs that were different between the two jeeps.

My best guess is that the front springs were replaced on the old Jeep at some point with heavy duty springs (I bought it used so I don’t know).

Is it possible that different rate springs could have been installed at the factory, or were they all the same?

Thanks!

 

[Rob Mayercik]

Hm. Maybe the rear leaf shackles are siezed on the 99.

May also be the shocks too - what does each of these vehicles have for those?

 

[89Mock]

It could be a lot of things like all new bushings and parts on the "new" XJ and old worn out parts on the old XJ. With no information other than a 2wd 1999 xj and a "new" xj it's hard to go on.

 

[Tim_MN]

Shocks absorbers tend to have the greatest effect upon the ride quality/feel. Tires can have a noticeable effect, as can different brands of lift kit springs.

I gave away a 6 month old set of Rancho shocks that made my XJ ride like dumptruck, and have thrown away numerous sets of Monroe and auto parts store generic shocks that were too floppy.

Stock springs or stock replacement springs should have the same ride quality/feel

 

[EvaB99XJ]

Let’s see - the 2 wheel drive XJ has new everything in the front. The shocks are mid range Gabriels that I bought at AutoZone, also fairly new.

The 4 wheel XJ has old worn out everything - I’m not even sure the shocks do anything on it. It’s getting a lift soon so the worn stuff will go away soon.

The 2 wheel drive Cherokee has what I’d call light truck street radials. The 4 wheel drive XJ has cheap car radials on it.

The harshness seems to be coming from the front on the 2 wheel drive Cherokee.

Maybe it is just the difference between the old worn out suspension and the fresh suspension?

 

[Tim_MN]

You are driving one of the finest examples of early 1980's automotive technology with solid axles, remember not to expect a Cadillac ride quality.

I don't buy cheap shocks at the auto parts store, I have been disappointed many times too often. YMMV.

Both of my daily drivers XJ's have Bilstein 4600 and the off-road rig has DoetschTech DT3000.

 

[asymptonic]

You are driving one of the finest examples of early 1980's automotive technology with solid axles, remember not to expect a Cadillac ride quality.

I don't buy cheap shocks at the auto parts store, I have been disappointed many times too often. YMMV.

Both of my daily drivers XJ's have Bilstein 4600 and the off-road rig has DoetschTech DT3000.

Yep, I put the Bilstein 4600s on and it smoothed my ride up. As a weird metric, speed bumps feel half their height from before.

 

[EvaB99XJ]

Mystery solved - It’s definitely the shocks. I replaced the old leaking shocks with the same shock that I have on the 2 wheel drive (they were on sale for $10 each new and are temporary until I put a lift on it) and they both ride the same now.

Thanks to all that responded!