Limited Slip Question

[Imagineer]

Forgive me for asking a dumb question, but also on the to-do list for this weekend is to get the Jeep front end off the ground to inspect and check all the steering and suspension bits.

An odd thing that’s occurred recently that I’m not sure is a real problem or just what you get with big tires and limited slip diffs.

When backing into my parking spot at work (on a concrete lot), if I turned the steering to near full lock (either direction), as the Jeep moved, it feels like the steering wheel is being pulled to the full lock position. Also, when I pull out of the spot, if the steering is at near full lock, the front end seems to jump a bit, sort of feels like the outside front tire is loose.

Is this just how a limited slip differential behaves?

Some background, this ’97 TJ has a 4” Rough Country lift and is on 35” x 12” tires (and I recently discovered it’s been re-geared with 4.10 gears).

Expecting that the speedometer would be off due to the larger tires, I used a GPS speedometer cell phone app to check. Rather than finding the Jeep was going faster than the Jeep’s speedometer was showing, it was actually going much slower (going 44mph when the speedometer showed 50mph). So I lifted the rear wheels off the ground, spun the wheel one revolution and counted the drive shaft revs. Sure enough, it’s got 4.10 gears. I checked each diff for a tag showing the ratio, but all there is a metal tag stating to “use gear oil for limited slip”.

 

[BlueC]

When backing into my parking spot at work (on a concrete lot), if I turned the steering to near full lock (either direction), as the Jeep moved, it feels like the steering wheel is being pulled to the full lock position. Also, when I pull out of the spot, if the steering is at near full lock, the front end seems to jump a bit, sort of feels like the outside front tire is loose. Is this just how a limited slip differential behaves?

What kind of limited slip is it? That sounds like a little binding, which I think Detroit and "lunch box lockers" are prone to.

Expecting that the speedometer would be off due to the larger tires, I used a GPS speedometer cell phone app to check. Rather than finding the Jeep was going faster than the Jeep’s speedometer was showing, it was actually going much slower (going 44mph when the speedometer showed 50mph). So I lifted the rear wheels off the ground, spun the wheel one revolution and counted the drive shaft revs. Sure enough, it’s got 4.10 gears. I checked each diff for a tag showing the ratio, but all there is a metal tag stating to “use gear oil for limited slip”.

That's a simple fix, and it takes about 10 minutes to correct when you have the part. What you need to know is your actual gear ratio and actual tire height, then go to any parts supplier like Quadratec or Extreme Terrain and find the correct spedo gear.

As for the limited slip tag, that was most likely for the original equipment. If it's been regeared, that might all have been changed, so what's actually in there?

 

[Imagineer]

What kind of limited slip is it?

I'm not sure what's in there. On the maintenance list is to replace all the fluids, so when I get the diff covers off, I'll take some pictures.

When I test drove it, it did seem really torquey. I asked the seller if it was re-geared and he had no idea (I think the limit of his wrenching skills was just buying big tires).

And I've ordered a 33 tooth speedometer gear

 

[BlueC]

I'm not sure what's in there. On the maintenance list is to replace all the fluids, so when I get the diff covers off, I'll take some pictures.

Getting eyes-on will be best. You'll also be able to verify your actual gear ratio.

 

[Strizzo]

When backing into my parking spot at work (on a concrete lot), if I turned the steering to near full lock (either direction), as the Jeep moved, it feels like the steering wheel is being pulled to the full lock position. Also, when I pull out of the spot, if the steering is at near full lock, the front end seems to jump a bit, sort of feels like the outside front tire is loose.

Mine started doing this when I put the lift on. before it would just rotate almost on the inside rear like all the other 2 doors i've driven. I assume it has something to do with my at home alignment, but I haven't messed with it too much since it drives down the road well enough.

 

[cpwolf]

I'm not sure what's in there. On the maintenance list is to replace all the fluids, so when I get the diff covers off, I'll take some pictures.

When I test drove it, it did seem really torquey. I asked the seller if it was re-geared and he had no idea (I think the limit of his wrenching skills was just buying big tires).

And I've ordered a 33 tooth speedometer gear

I got no problem taking replacing fluids, but you can throw it up on jack stands pretty quickly and turn the tire and watch the drive shaft. 4.56 or 4.88 might be tough to see without marking it, but you'll be close to what gears you have.

 

[TheBoogieman]

When backing into my parking spot at work (on a concrete lot), if I turned the steering to near full lock (either direction), as the Jeep moved, it feels like the steering wheel is being pulled to the full lock position. Also, when I pull out of the spot, if the steering is at near full lock, the front end seems to jump a bit, sort of feels like the outside front tire is loose.

Sounds like your tires are rubbing your lower control arms. Make sure you're running about 25 psi in those tires also.

 

[Imagineer]

I got no problem taking replacing fluids, but you can throw it up on jack stands pretty quickly and turn the tire and watch the drive shaft. 4.56 or 4.88 might be tough to see without marking it, but you'll be close to what gears you have.

I'm 99% certain it's got 4.10's, The driveshaft rotated only a bit past 4 revolutions.

Also, I did the math. Factoring in the larger 35" tire diameter and that the GPS was showing the 6mph slower than the OEM speedometer display, the gearing had to be something near 4:10.

 

[Imagineer]

Hopefully the last noob question... What are the symptoms of a limited slip front diff that doesn't have sufficient lube? Would the sharp corner binding condition be worse?

I ask, because earlier today I was backing out of a tight parking spot (on asphalt) with the steering at full lock to the right, and it felt like one or both front wheels would not rotate. I used a touch more throttle and it felt and sounded like the front tires were dragging sideways.

Other than at or near full lock steering, the Jeep rides fine.

 

[Brianj5600]

Pulling the covers would help to determine what differentials. Post some pics w/o the covers. See if any pieces are in the bottom of the pumpkin.

 

[BlueC]

Hopefully the last noob question... What are the symptoms of a limited slip front diff that doesn't have sufficient lube? Would the sharp corner binding condition be worse?

Are you positive that you have a LSD up front? I've seen worn spider gears try to bind up when turning sharp.

To check the oil level, pull the fill plug. The oil level should be at or just below the hole.

 

[KennethS]

it's got 4.10's

something near 4:10

Ack. I was impressed you had it right, then you went and messed it up. Those two are not the same thing.

 

[Imagineer]

Whereas I don’t enjoy admitting when I’ve goofed up, I’m not too proud not to.

For about the past month or so my ’97 TJ has been giving me trouble in sharp turns. The front end seemed to be binding up when turning at or near full lock, in both forward and reverse.

So, in anticipation of a somewhat expensive repair, I’ve been studying up on differentials, limited slips and such.

Yesterday, I found myself with about a half hour of spare time and decided to quickly replace the speedo gear with a 33 tooth one to correct the speedometer reading.

1st road test after replacing the gear . . . nothing. The speedometer didn’t move. Back under the Jeep, tried another notch setting, went for a quick spin and . . . nothing, still no speedometer.

Since there were two more notch settings to try out, I decided, rather than waste more time going for drives, I just put a floor jack under the rear diff and jacked up the rear wheels off the floor.

3rd trial, started the Jeep with the rear wheels off the floor, put it in gear and eased off the clutch and . . . the Jeep crept forward!!

Turns out, over a month ago when I had the seats and console out for pressure washing, after reinstalling the console, I didn’t ensure the transfer case lever was all the way down into 2-Wheel HI.

Bottom line, the speedometer is fixed, the Jeep in is 2W-H and I learned a valuable lesson.

 

[cpwolf]

Whereas I don’t enjoy admitting when I’ve goofed up, I’m not too proud not to.

For about the past month or so my ’97 TJ has been giving me trouble in sharp turns. The front end seemed to be binding up when turning at or near full lock, in both forward and reverse.

So, in anticipation of a somewhat expensive repair, I’ve been studying up on differentials, limited slips and such.

Yesterday, I found myself with about a half hour of spare time and decided to quickly replace the speedo gear with a 33 tooth one to correct the speedometer reading.

1st road test after replacing the gear . . . nothing. The speedometer didn’t move. Back under the Jeep, tried another notch setting, went for a quick spin and . . . nothing, still no speedometer.

Since there were two more notch settings to try out, I decided, rather than waste more time going for drives, I just put a floor jack under the rear diff and jacked up the rear wheels off the floor.

3rd trial, started the Jeep with the rear wheels off the floor, put it in gear and eased off the clutch and . . . the Jeep crept forward!!

Turns out, over a month ago when I had the seats and console out for pressure washing, after reinstalling the console, I didn’t ensure the transfer case lever was all the way down into 2-Wheel HI.

Bottom line, the speedometer is fixed, the Jeep in is 2W-H and I learned a valuable lesson.

Ooof, yeah, oof, ha.

Good thing you didn’t start pulling things apart…ha.

Better to find it like this, although on rear jack stands and the jeep creeps…little bit of a shorts dirtier…

 

[Mudflat]

Mine has limited slips front & rear, 33” tires & a 3” suspension lift. I don’t have the symptom that you described. I’m guessing that you might have an alignment issue caused that.

 

[sab]

I’m guessing that you might have an alignment issue caused that.

You nailed it. His transfer case shift lever was misaligned!

 

[cpwolf]

You nailed it. His transfer case shift lever was misaligned!

Exactly

 

[cpwolf]

Mine has limited slips front & rear, 33” tires & a 3” suspension lift. I don’t have the symptom that you described. I’m guessing that you might have an alignment issue caused that.

You might want to finish the thread, he realized he’s been in 4wd the whole time