Let me see if I can explain this right.

By back tires appear to be pointing to the left but the front tires are driving straight and it feels like I am driving straight.

A buddy of mine was behind me and told me that it looked my bed was shifted to the right compared to the rest of the truck as if the frame is bent but it’s not and has never been wrecked.

Also, the gap between the tread of my rear tire and the forward part of the rear wheel well on the passenger side is tighter than the gap between the tire tread and the forward part of the rear wheel well on the driver’s side.

I just recently had the front end aligned after my new tires and I have had 2” rear blocks for the past 2+ years. Now I do have some wimpy u-bolts holding my 2” blocks in place but the leaf springs don’t appear to be shifted.

Does anyone know what the deal is?

If you don't have a broken main leaf on one side then the likely culprit is the centering pin in the sprig pack is not properly indexed into the lift block or the center pin in the block is not indexed into the spring perch on the axle.

Poeple tell me my truck does the same thing when they are behind me. ???? Wonder what it is?

I see LOTS of cars and trucks on the road doing this. Cant say I know what it is, but its very common.

I think it is perception......most of em anyway. If you were to look down the other side of the truck while going down the road it would probably look the same. The track width on the front of GM's trucks have always been wider and give the illusion that it is dog tracking.....from the rear anyway.

I am not saying it is not possible that someone may not have a genuine problem....just that this is how it ends up being most of the time. Drive the truck through a puddle of water and check the tracks.....

Also, my block does not have a hole for a pin, just the leafs do.

http://memimage.cardomain.net/member_images/5/web/461000-461999/461257_30_full.jpg

Also, my block does not have a hole for a pin, just the leafs do.

ChevyHDGert...if you do not have a centering pin on the axle side of the block and a centering hole for the leaf spring to sit in and that is just a steel block, the simple answer is that your axle is not properly centered.

Why does GM use a wider front track than rear track. 4" on older HD's and 2.5" on newer?

I'm not sure what the actual measurements are Rich, but I believe the reasoning behind it is handling.

Why does GM use a wider front track than rear track. 4" on older HD's and 2.5" on newer?

MMM I don't see what you folks are talking about. OOOH :eek: I have four tires on the rear axel :cool:

You get a 4 wheel alignment? That'll tell you better than anything else. Most vehicles no matter what you do will dogtrack a little bit. Easy way to check if you really are is to find a dry spot of pavement, spray your tires down with some water or something in a spray bottle, and drive straight forward for a bit while your wife or someone keeps hosing the tires down so you can see exactly where your tire tracks are. That'll tell if your rear end is out of wack real cheap and easy.

Fixing it, these guys know more than me about that.

I've been doing bodywork for over 20yrs., so would like to share my experience with you. When a truck is dogtracking the first thing to measure is the center section of the frame. the center section is where people sit[the cab]. What you do is take an X-measurement from a location on the frame that is A-symetrical. Take the 2 measurements and see if there is a different. Very few full framed vehicles are perfect. When the measurment is way off that is call a dimond in the center section. A half an inch is ok, but 1 inch is too much, it would have to be pulled a half an inch. Here is a quick test, water down a section of the road good enough to get all 4 wheels wet when driving though it and see how it tracks on the dry pavement. What has me concerned is that you installed 2 inch blocks, that might be your problem. Aonther result of dimond is the a different in the gap between the rear bumber and the bed, must be noticable. Hope this helps.

I had a similar problem with this too. I made a u-turn and I heard something. Did not bother to check. As I was getting home every time I braked the rear end was sliding. Once I pulled in to my driveway I got off and checked the rear and sure enough the center pin was broken off the right rear. Took it back to the lift shop and they had to replace the shim and center pin. Lift shop told me that it is a good idea to tighten up the U-bolts once a month. Since I don’t have any traction bars he said he strongly recommends me getting them to stop the rear end from hopping.

I think it is perception......most of em anyway. If you were to look down the other side of the truck while going down the road it would probably look the same. The track width on the front of GM's trucks have always been wider and give the illusion that it is dog tracking.....from the rear anyway.

I am not saying it is not possible that someone may not have a genuine problem....just that this is how it ends up being most of the time. Drive the truck through a puddle of water and check the tracks.....

Exactly...

I would definitely NOT recommend blocks under any springs. Leave that to Ford and Dodge. I'd sugest adding a leaf and arching the springs over blocks. Unless the blocks were old and rotten in the pilot bore, they are not likely the cause, but nevertheless, you could pull them and check that they are good and that the hole/pin are directly across from each other...

I see this often. I don't know what causes it - prob uncentered rear axle but it looks strange. It's the first thing I checked before I bought mine. It's not a perception.

Poeple tell me my truck does the same thing when they are behind me. ???? Wonder what it is?

It is because your track width is wider with the RCD lift, It appears your truck is dog-tracking when seen from behind.

My suburban did that after an accident, it was a broken eye on the leaf spring. The front end is wider than the rear axle so GM could save money and use a standard rear axle and not have to make one 4 inches wider:mad: