Dog tracking 3500

[Ole Blue]

My 3500 4x4 dog tracks when in 4wd on snow/ice packed roads. Take it out of 4wd and it drives normal. Took it to the dealer today was told thats normal for a dualie. I have had the anti-spin replaced once but only one side spins when on wet grass or in mud. If you lock it in 4hi and turn the wheel a 1/4 of the way the truck jumps up and down. Dealer told me it jumps cause it has to much traction and doesn't need to be in 4wd. I asked if the truck only spins one rear wheel and won't move itself so you have to put in 4wd then if you turn it jumps up and down ,ain't something wrong? Dealer said not that they can find,but will call DC and ask them. Said will let me know monday. Has anyone else had this problem? It seems to me like when in 4wd the rear end is going faster than the front. Any and all help would be appreciated... ..... Blue

 

[HC]

My 3500 4x4 dog tracks when in 4wd on snow/ice packed roads. .
... only one side spins when on wet grass...
... in 4hi... turn the wheel... the truck jumps up and down.

Blue, Not just every day you and I get to discuss snow and ice handling, is it?
First, educate me on the term "dog tracks" - do you mean tending to follow the ruts vs. driving where pointed, or are you describing something different?
I'm not a duallie, but my observations driving to work two days ago on the interstate were that when I started sliding too much or had to pass someone in the "bad" lane, I was still much better off in 4WD. I didn't feel 100% stable, but I think it was just characteristic of an extremely heavy front and almost unloaded rear, and 4WD was still far better than 2WD. I have since purchased some bags of sand, so if it gets nasty again we'll see if how much difference some extra weight makes.
On your limited slip performance: I have a question for our resident experts - can somebody explain the difference (if any) between the Chevy Limited Slip and Dodge Limited slip? What causes the limited slip to activate - does the spinning wheel have to spin fast? I rode in a Chevy the other night, and we found a ditch that you could drive over at low speed so that the truck would balance on one front and one rear wheel, with the other two wheels almost completely off the ground. If he drove slowly, he got no limited slip action and we could not climb out of the ditch. If he gassed it and spun the rear wheel rapidly, there was a solid "clunk" and the differential appeared to lock almost solid, because the truck then performed like it had a mechanical locker and drove right out. But my key point is, it was not how many times the wheel turned, but how fast it turned, that determined whether or not the limited slip mechanism activated. So it the Dodge like that, do you have to spin the tire fast, or is it more like the Auburn units which I believe build up friction for each turn of the spinning wheel, even at lower speeds? This question is important for all those who feel that their limited slips are not working - first we have to know what "normal" is!
Blue, your last question, about "jumping up and down" - mine does this on soft gravel, but locking in seems to help. I believe our rear leaf springs allow the rear to "wind up" because they allow the axle housing to rotate a bit. If you were going in a circle in 4WD, this could wind up the rear axle because the front and rear axles are travelling different distances; when it finally develops too much force to hold, it will release by spinning the rear tires and you get a hop at that time. If you search old threads on "traction bar" or "bunny hop" you will find some aftermarket devices that help control this tendency, but I have decided it is not bad enough to spend money on. I may change my mind later, but there are other toys I want worse than traction bars! In other words, I do think this hop is normal.


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2001 ETH, QC, LWB, 4WD, 3. 54, SPA Pyro & Boost, K&N RE-880 w/foam pre-cleaner, ARE Z-series Cab-high shell, Rear ARB locker, and all kinds of synthetic fluids...

 

[Scooby]

In other 4X4's I have experienced this hopping and it's usually due to not enough tire slippage when turning - esp. noticable in 4WLow. I beleive it's caused by too much grip and the final drives of the front and rear not being exactly the same. You haven't had just one of the pumpkin's restuffed, have you? (you haven't changed gear ratios, right?)... .

 

[Bad340fish]

The hopping up and down on turns is from gear bind. What happens is in a tight corner your front and rear wheels spin at different speeds. since there is no center differential it tries to twist hop or bounce the truck around. Gear bind is VERY hard on transfer cases and differentials. If you need to turn sharp on a tacky surface take it out of 4wd. Of coure if your on a tacky surface why are you in 4wd? #ad
If your on snow ice mud sand ETC turning sharp in 4wd is ok becuase the tires can easily slip to comensate for it.

Clark

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Clark
1999 2500 QC SB 5spd all stock for now
1968 Barracuda Formula S Viper Blue 11. 98@112

 

[Ole Blue]

In answer to the question dog tracking:When on ice or snow packed roads,here they don't plow the snow off all the way to the pavement they leave about 2 inches of hard packe snow or ice,my truck will run about a half of a tire width to the right in 4wd. It is not following other ruts,it will do this uphill,downhill,around corners. Put it in 2wd it drives fine. To being wreaked :no To having differant tires:no still factory Goodyears To differant gears:what it came from DC with,but it acts like the rear is faster than the front to me. As to the jumping up and down in 4wd turning,it acts like you have it turned all the way to the stop on a hard surface in 4wd. Only this truck does this at 1/4 turn of the sterring wheel. My dealer says my truck is normal but would let me know what DC says monday. Thanks for the input... ... Blue

 

[HC]

To differant gears:what it came from DC with,but it acts like the rear is faster than the front to me...

B. G. - I knew that was one I should know, but I figured better to show my ignorance now than to live with it forever... #ad


Blue - Check tire pressure and wear - sounds like your front might be low, makes it act like a smaller diameter tire, which would make the rear faster. Raise the pressure in the front, drop the pressure in the rear, see if this evens things out. Also, measure tread depth - if front is worn more, that could be a factor.

 

[NVR FNSH]

Also on a dually, you have four tires pushing the front end, and two pulling, which makes the rear attempt to pass the front. Throttle pressure reduces this action by applying equal power to both ends, overcoming the difference in wheel speed, and driving all four (actually two) at the same speed. The inside front then spins, pulling you to the direction you want, and the rear pushes it.
...

Ol Ron,
Can you explain what you mean by this? I don't follow... .....

Brian

 

[jjohnson1177]

This may be a stupid question but has your truck ever been wreaked or taken a hard hit of some sort the the differentials? If the frame is bent or the axals aren't square with the frame a vehcile will go down the road side ways. With yours doing it in 4x4 only I think I would check the alignment of everything, good luck!

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2001 3500 ETH/DEE, Black and loaded, chief transportation for three hayburners.

 

[B.G. Smith]

HC, I find it hard to believe that you live in Conway Arkansas and don,t know what dog tracking is. Ain't you ever seen an old hound trot down the road with his hind end trying to get in fron of his front end? Just kidding, I have relatives who are from Conway. On the 3500 dog tracking, are any of your tires different brands or diameter?

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White 99 3500, QC, 3:55, auto. most options except leather, Line-X bed liner, fiberglass running boards Rancho 9000s, bug shield and window vents, black vented 5th wheel tailgate, 100 gal. aux. fuel tank.

 

[Mike Sisk]

Hmm, I've had two 4x4 3500 and I find they don't drive that much differently than a non-training wheel equiped truck in snow, ice and other slushy stuff. Heck, this past week has been pretty much like that here in New Hampshire and mine's been fine. You do get more floatation in the rear and it might dogtrack from time to time but not all the time.

It sounds to me that 'Ole Blue's problem is that he has different gear ratios in the front and back. He did mention he had the rear differential replaced at one time. I would not be surprised if the dealer replaced the gears at the same time with the wrong ratio.

You shouldn't get driveline binding at 1/4 turn of the wheel on such a long wheel base truck--I know I don't even on dry pavement.

 

[HC]

It sounds to me that 'Ole Blue's problem is that he has different gear ratios in the front and back. He did mention he had the rear differential replaced at one time. I would not be surprised if the dealer replaced the gears at the same time with the wrong ratio.

Warning: LONG! This one has tickled the "solve the mystery" bug in me.

Mike, you might be on to something! Blue, did your truck come with 4. 10's? If they somehow stuck 3. 54 in your rear, your rear would be about 15. 8% faster. Or if you started with 3. 54's, then maybe they found something around 3. 23 that fit? That seems like a lot to me; I would expect binding and hopping even with the steering wheel not turned at all, But maybe it loads up different going in a straight line? Also, you should have noticed a drop in rpm right after the axle work at your normal cruise speed.

Anyway, I think we can easily test these theories: Put it in 4WD on grass, drive forward to take slack out of the gear train, stop, put a piece of tape on each tire (let's say at the bottom sidewall) and drive forward again 1 turn. If the gears and tires are the same, both pieces of tape should end up exactly the same, on the bottom. If the front outruns the rear by about 15", then I would say you have 3. 54 rear, 4. 10 front, because that would mean your front is turning faster. (Worded differently, your rear is going further per turn, so it tries to "outrun" the front. Anyway, if you come up with some other number (but not 0"), and tires are identical, then I would start reseaching what other Dana axle ratios might exist that could have fit in the same housing as whatever you started out with. Even 245/75R16 rear with 225/75R16 front could cause a 3" difference in our "rolling on grass" test, would be visually difficult to spot, would only drop your rpm by 70 rpm at 70 mph, but would show up as a major difference in handling when in 4WD...
I also see from coopertire.com that even changing from Load Range E to Load Range D in the exact same model and size can cause a 0. 3" difference in our test - this would be almost impossible to measure, but might be enough to cause the hop you describe. This means even if you have the same size on both ends, but different brands, then there could be a minor diameter difference. Also, is one set of tires newer than the other? That would cause this too.
The weather is going to get nasty again; maybe all you really need is a set of 6 new, same size, same brand tires!
Good luck in finding your "gremlin", and keep us posted!

[This message has been edited by HC (edited 12-17-2000). ]

 

[Fireman Dave]

Okay, HC, you've got me scratching my head. Wouldn't the wheels need to be off the ground to give the result you're looking for? It seems to me that if the front tires turn exactly one revolution, the rear tires will also turn exactly one revolution - provided the front and rear are attached to the same truck and that the tires are the same size, the truck is going straight, and the traction conditions are identical. If the front and rear gears ratios are different, there would be a difference inside the carriers, but I think if the front tires go one revolution, the rear tires have to also. Two different trucks side by side with the same size tires and different gear ratios would show us the difference in the rolling in grass test. I'm only questioning the test. I think the theory that there may be two different ratios in Blue's truck is very plausable.

Having said that, please forgive my ignorance if I'm all wet on the subject. #ad
It is a brain tickler, isn't it! #ad


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2001 2500; SLT; 4x4; QC; LWB; Auto; 3. 54 LS; 265s; Camper; Tow; Sliding Rear Window; Travel Convenience Group; Cab Clearance Lamps; Forest Green

 

[C1B1DIESEL]

Here is another test.
put truck in 4wd. mark drive line and tire. turn wheel on rev. count how many times drive line turns. 3. 54 will turn 3. 54 times and 4. 10 will turn 4. 10 times.
front axle has to be ingaged to do the front.
hope this helps

 

[HC]

Wouldn't the wheels need to be off the ground to give the result you're looking for? ... . I'm only questioning the test... . I think the theory that there may be two different ratios in Blue's truck is very plausable.

Awwwk! Dave, you've got a point; I'm rethinking... on second thought, my grass test will show different axle ratios as I described, but, it needs to be modified to show the effects of different tire sizes on axles that have the same ratios. Check my (revised) logic:
If the gear ratios and tire sizes are the same, then in 4WD a given number of engine revolutions will turn both driveshafts and both sets of wheels exactly the same number of turns, and both wheel sets will travel exactly the same distance with no slippage required on the grass. Both marks (front tire, rear tire) will end up dead bottom center after one revolution. Now, change only the gear ratios in one differential. Because of the transfer case, the front and rear drive shafts still turn exactly the same number of turns. But the 3. 54 differential will try to rotate it's wheel set more rotations. Because the truck is on grass, the wheels will in fact rotate more on the 3. 54 end of the truck, the tires will slip in the grass (because the gears won't give) and the tape will not end up bottom dead center on both front and rear.

Now, do this experiment again - assume all gearing is the same, front and rear, and the only change is in tire diameter. Because the gears are all locked together, both front and rear hubs will turn exactly the same number of revolutions. Because the wheels have different diameters, one set will "try" to travel further, but it won't, it will just slip. But in this case, the tape will still be bottom dead center on both ends of the truck. So for checking tire size, my "grass" experiment needs to be modified - put the truck in 2WD, and roll forward 5 or 10 turns of the wheel. If the tires are exactly the same size, the tape on both wheels should still be bottom dead center even after several revolutions (if going in a straight line). Or, Blue could do this part the old fashioned way and just read the sidewall, verify all tires are exactly the same brand, same model, same size, same load rating, etc, and measure tread depth if they are of different ages.

Thanks for making me think this through again! #ad
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[This message has been edited by HC (edited 12-17-2000). ]

 

[Ole Blue]

I went to my dealer this morning for DC's answer to my dog tracking problem. They told me they had been too busy to call,come back this afternoon. Well,guess what?When I went back at 3pm they still hadn't called. But would let me know by going home time. At 5pm still no word. Tomorrow I think I will find the owner of the dealership and sit on his desk untill I get an answer... ..... Blue

 

[Fireman Dave]

HC:
You just blew my mind! #ad
#ad

 

[Ole Blue]

Went back to my dealer yesterday. They still hadn't called DC. I got mad and called the 800 number in my owners manual. The lady there told me she would find out why my dealer wouldn't call. Went back to dealer this morning,they told me DC says its the nature of the beast to jump and buck in turns when in 4wd. I said BULLS**T I have had to many 4wd trucks to know better. I told the service manager lets go drive a new dualie and see what it does. It did the same thing . Maybe I am wrong but none of my other trucks ,Chevy and Ford,have done this. My dads '00 doesn't. I'm stumped. I did take HC's advice. I put a piece of tape on both front and rear tires at the bottom. I move the truck one front tire revolution. The rear tire was a half an inch off. The tire size is the same,but with all the weight on the front the roll out is less. I aired my front tires to 85psi with 60psi in rear,now the roll out is the same. Maybe this will cure the dog tracking but may increase tire wear. By the way DC said if you are on ice and snow how the truck tracks doesn't matter as long it drives normal in 2wd on good roads. So much for having a 4wd for bad weather..... Blue

 

[Cooker]

Didn't read the entire thread, but to comment on the truck "bucking" in turns in 4wd on dry pavement, I believe this is totally normal. My Cummins is my 5th 4wd (2 Dodge, 3 Chevys) and all have done this. In fact, when I test drive them before I buy I do a turn test on dry pavement in 4wd to make sure the 4wd works.

Driving in 4wd on dry pavement is very hard on the drivetrain, especially turning. For daily driving, I don't use the 4wd on my truck unless I'm sure the road is completely snow covered.

Just my thoghts,
Ryan

[This message has been edited by Cooker (edited 12-21-2000). ]

 

[HC]

I aired my front tires to 85psi with 60psi in rear,now the roll out is the same. Maybe this will cure the dog tracking but may increase tire wear... Blue

If you decide to "air up" the front during the next snow and ice storm (or "air down" the rear), be sure to let us know how she handles! I know I'm going to readjust pressures to better match my usual "light load" condition. Seems like if we do it just right, tires should still wear evenly...

 

[HC]

OK, I know I've flapped my lips too much, so I'll try to make this my last post on this topic. But I "did the math", and wanted to share the results:
Blue reported a 1/2" difference in roll-out before adjusting tire air pressure.
At 30 mph, the wheels are turning 5. 5 revolutions per second on this truck, or about 10. 0 revs per second if you make it up to 55 mph. Putting it another way, if Blue cruises at 30 mph on the slippery stuff, every 4. 5 seconds one end of his truck is going to try to travel about 1 foot further than the other end. This is probably especially noticable for a light-load on a dually, because each of the four rear tires is carrying only 1/2 of the load seen by a 2500 series truck carrying the same payload.
I don't know about the rest of you, but I will be adjusting my tire pressures before driving on snow and ice again! #ad