01 excursion violent shaking when spinning
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VT Chapter Ldr
Joined: Apr 2004
Posts: 96,160
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From: Orange, Vermont
01 excursion violent shaking when spinning
Question, my excursion has limited slip in the rear. Recently when in snow and spins I’m getting a lot of shaking when it spins. Does it need more friction modifier? I haven’t changed the fluid in the rear for 4 or so years. Thank you
Laughing Gas
Joined: Jun 2017
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From: CSRA, SC
Sounds like wheel hop. It happens on our rigs in low traction conditions as the wheel is gripping and then not back and forth and makes the wheels jump. The only way I know to fix it is add traction bars. Excursions have relatively soft springs which make ours extra prone to wheel hop. If you have a lifted truck on blocks or something that makes it even worse.
FTE Remembers
Joined: Apr 2011
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From: Northern California
oh and the Excursion came stock with a traction bar which works great as long as the rubber bumpers are intact.
FTE Remembers
Joined: Apr 2011
Posts: 8,259
Likes: 346
From: Northern California
as far as shaking when a rear tire is spinning, hard to tell without seeing it happen but the effect I am familiar with I would describe as a chatter more than shaking.
happens when either the ratio of friction modifier is not correct or the clutches are worn. think clutch chatter in a stick shift.
happens when either the ratio of friction modifier is not correct or the clutches are worn. think clutch chatter in a stick shift.
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VT Chapter Ldr
Joined: Apr 2004
Posts: 96,160
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From: Orange, Vermont
Maybe wheel hop. It was in soft snow going up my driveway so both wheels probably had equal bad traction. I do believe both rubber stoppers missing. I’ll try to remember to look tomorrow
FTE Remembers
Joined: Apr 2011
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From: Northern California
fixing your stock traction bars will help the rear but obviously not the front which in my experience tend to hop pretty bad on leaf sprung vehicles in that situation. air down helps tremendously and when that fails letting off the throttle is the fix.
should be noted, of the dozen or so broken locking hubs and several axle shafts where all done in my driveway. of course my driveway is a steep twisty road in the mountains that gets 3 feet of snow at a time.
Laughing Gas
Joined: Jun 2017
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From: CSRA, SC
Throw me a bone. I'm not afraid to be wrong just offering my current understanding. I learn much more when I'm wrong than when right.
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FTE Remembers
Joined: Apr 2011
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From: Northern California
the excursion does not have “soft springs”
that was started by the kook who was making Landyot radius rods as marketing spew to convince people they needed his poorly engineered product.
in fact the Excursion rear spring rate is 420 lbs per inch which is very likely the stiffest main spring pack you are ever going to find in any passenger vehicle, SUV or truck.
that said there are improvements to be made to the Excursion suspension to be sure, but “soft springs” is not one of them. in fact the Ex works much better with a softer then stock rear spring at about 380 lbs pet inch.
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Laughing Gas
Joined: Jun 2017
Posts: 836
Likes: 126
From: CSRA, SC
thats ok cause I cant spell. lmao. obviously meant killed.
the excursion does not have “soft springs”
that was started by the kook who was making Landyot radius rods as marketing spew to convince people they needed his poorly engineered product.
in fact the Excursion rear spring rate is 420 lbs per inch which is very likely the stiffest main spring pack you are ever going to find in any passenger vehicle, SUV or truck.
that said there are improvements to be made to the Excursion suspension to be sure, but “soft springs” is not one of them. in fact the Ex works much better with a softer then stock rear spring at about 380 lbs pet inch.
the excursion does not have “soft springs”
that was started by the kook who was making Landyot radius rods as marketing spew to convince people they needed his poorly engineered product.
in fact the Excursion rear spring rate is 420 lbs per inch which is very likely the stiffest main spring pack you are ever going to find in any passenger vehicle, SUV or truck.
that said there are improvements to be made to the Excursion suspension to be sure, but “soft springs” is not one of them. in fact the Ex works much better with a softer then stock rear spring at about 380 lbs pet inch.
Its okay I knew what you meant. At 420lb/in wouldn't that be the softest spring of any Super Duty (or SD based) vehicle? Or, when you say stiffest main pack, do you mean for the SD pickups the stiffer rate is coming from overload springs/ other source?
FTE Remembers
Joined: Apr 2011
Posts: 8,259
Likes: 346
From: Northern California
At risk of highjacking this thread...
Its okay I knew what you meant. At 420lb/in wouldn't that be the softest spring of any Super Duty (or SD based) vehicle? Or, when you say stiffest main pack, do you mean for the SD pickups the stiffer rate is coming from overload springs/ other source?
Its okay I knew what you meant. At 420lb/in wouldn't that be the softest spring of any Super Duty (or SD based) vehicle? Or, when you say stiffest main pack, do you mean for the SD pickups the stiffer rate is coming from overload springs/ other source?
the secondary, aka “overload” ( no manufacture calls them overload for obvious reasons ) on the 250/350 is 670 lbs.
in the case of the f250/350 the suspension uses a multi stage system, the rear has a total of 8” of travel. for the first 5.5” of travel the main pack does all the work. the last 2.5” of travel the secondary stage ( bottom thick leaf ) comes into play. this is done to make certain the heavy payload trucks carry can almost never bottom out. several good reasons for this, foremost if the axle is traveling upwards from contact with an obstacle and were to bottom out on the frame any upward inertia energy that is remaining goes 2 places. 1. into the chassis, causing the vehicle to lurch violently likely causing a crash. 2. when the frame stops the axle tube traveling up the outer ends of the axle keep moving resulting in a bent axle.
basically a secondary spring on trucks is a long travel bump stop. your excursion uses a rubber bump stop with about and inch of travel,
the truck gets it payload capacity by
1. having a lower curb weight do to less rear body work then the ex. therefore it can haul more stuff other then bodywork.
2. longer travel.
edit.... For comparison sake. the Ex has 5.5 of total travel
FTE Remembers
Joined: Apr 2011
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From: Northern California
short answer is i need more info on your setup to mitigate, likely a wheelbase vrs trailer setup. look forward to the conversation.
Fleet Mechanic
Joined: Oct 2010
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From: South Eastern Michigan
As for the OP question, I replaced the springs on mine a couple of years ago (with ATI) and it drives like a new truck. I did the shocks the previous year. Everything that came off was the original stuff and it was way past done. The first thing to start with would be the diff fluid, its the cheapest step. I would steer clear of any rear cover that adds fluid capacity. There is an OEM aluminum ribbed cover you can get....get longer bolts too, OEM ones.
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