Wondering blazer needs help.. SOLUTION FOUND! THANX

[sandSStorm]

This is my first post.

I own a 79 blazer that Ive been moding. The last mods were the front and rear diff from an older unit along w some old used 35's. I swaped the diff because the ones from the donor truck had 3.73's and a locker in the rear.

After all that was done I noticed that the truck will pull to the left while taking off. I have to correct by turning the steering wheel the oposite way. And then I have to return to when stopping. Its very anoying. Ive never had this problem before the swap. My friends and I have checked it all over for everything we can think of and nothing. All the joints seem tight, nothing feels loose. I even took it to an alignment shop and they could not come up with anything.

One thing that I have to try is re-installing the sway bar since I took it off a while ago. I only use this truck for offroading so I removed the swaybar for better articulation. Even after I removed it (when i had the other diferentials) I had no problem w it.

If anyone has any imput on this please post it. Its driving me nuking futz!!

PS- the problem is not there all the time, some times it wonders and if i try to duplicate the problem it doesnt do it. It only does it while going from 1 to 2nd gear.

The truck now has an np205 and a diferential without lock-outs.

Thanks

 

[blazinzuk]

what kind of rear diff do you have I assume a 12b is it like a lock right or a detriot or a gov loc or an auburn or what need more info

 

[1-ton]

The old tires are not doing you any good. It sounds to me like your rear thrust angle may be bad. By "thrust", I mean the alignment of your rear differential. Try having somebody follow you down the road behind you, and see if they can see the truck tracking down the road almost sideways. This is most commenly refered to as "dog legging" by most alignment techs. A bad thrust angle can be caused by a few things...loose or broaken U-bolt, Broaken/worn out/incorrect size leaf spring centering pin, worn out spring bushings, or a bent spring perch or weld that is cracked.

 

[goldwing2000]

It's actually called "dog tracking".

He said the alignment shop checked it out and didn't find anything, though. They definitely would have noticed a bad thrust angle.

I know it seems like an obvious solution but mine does that when I have it in 4WD on dry pavement.
Since you're not running lockouts, is it possible that you're stuck in 4wd?

Just a thought.

 

[sandSStorm]

what kind of rear diff do you have I assume a 12b is it like a lock right or a detriot or a gov loc or an auburn or what need more info

Its a 12 bolt diff w a detroit locker. Someone did mention that the locker may be bad soI tookit all apart and found nothing, the locker looks like new.

 

[sandSStorm]

It's actually called "dog tracking".


Since you're not running lockouts, is it possible that you're stuck in 4wd?

Just a thought.

I discarded that possibility since I never had that problem before. I already had the transfercase in for over a year. It all started after I installed this new diffs.

 

[sandSStorm]

A bad thrust angle can be caused by a few things...loose or broaken U-bolt, Broaken/worn out/incorrect size leaf spring centering pin, worn out spring bushings, or a bent spring perch or weld that is cracked.

We did lookinto those. We actually checked the suspension while power braking it and also by chokin the tires and switching between drive and reverse. We have rocked the blazer from side to side and had someone check for any source of play underneath and found nothing..

Ive almost given up on the project just because of that. And I know it shouldnt bother me since Its not my daily driver. Its just my beater. But it is driving me krazy. My friends and I are very good mechanics, one of them is a certified mechanic too and were baffled...

 

[1-ton]

It's actually called "dog tracking".

WRONG, It is called "dog legging" because of the way a vehicle tracks down the road like a dog with three legs...sideways. But WTF does it matter in the first place anyway?

 

[1-ton]

We did lookinto those. We actually checked the suspension while power braking it and also by chokin the tires and switching between drive and reverse. We have rocked the blazer from side to side and had someone check for any source of play underneath and found nothing..

Ive almost given up on the project just because of that. And I know it shouldnt bother me since Its not my daily driver. Its just my beater. But it is driving me krazy. My friends and I are very good mechanics, one of them is a certified mechanic too and were baffled...

Well, all I can say is the symptoms you described are very common to a thrust angle problem. If your rear diff is locked into a bad position, loading the suspension will not show up by power braking it. All I can say is...try having somebody follow behind you down the road "just for sh!ts and grins". The previously mentioned broken ring pinion, locker, axles, locked in 4X4...also can cause the symptoms you are describing.

 

[sandSStorm]

Thanx 1 TON, Well try that. As soon as the snow stops flying..

Anyone else have any more imput?

 

[pumpkin]

Sounds like a locker. If bothe rear tires are nt the same radius from the center of the axle to the ground, when you are on the gas the truck will go one way, then when you off the gas it will go the other way. Thats just one of the vices of a locker. This can be caused by uneven tir wear, or uneven tire preasure. I get the same in my Blazer. I'm used to it, and it lets me know when I am low on air on one of the rear tires.

 

[sandSStorm]

Sounds like a locker. If bothe rear tires are nt the same radius from the center of the axle to the ground, when you are on the gas the truck will go one way, then when you off the gas it will go the other way. Thats just one of the vices of a locker. This can be caused by uneven tir wear, or uneven tire preasure. I get the same in my Blazer. I'm used to it, and it lets me know when I am low on air on one of the rear tires.

Thats exactly what a friend of mine told me but I didnt believe it. I had a 94GMC full size with an EZ locker in it and it never did anything like that. The 94 was auto and the blazer is manual, would that be the differience?

 

[sandSStorm]

UPDATE!!

I just installed some 40" TSL swampers and the truck still pulls to the left...

I swear, Im gonna kill someone...

AAARRRGGGG!!!!

 

[goldwing2000]

WRONG, It is called "dog legging" because of the way a vehicle tracks down the road like a dog with three legs...sideways. But WTF does it matter in the first place anyway?

WRONG. It is called "dog tracking" because of the way ANY dog runs. They run diagonally, so their hind legs are between their front legs for clearance.

See Autozone's description here: http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/11/fa/b8/0900823d8011fab8.jsp

And check out pages 3 & 7 of this pdf from Hunter (you know... the people who make alignment machines):

http://www.hunter.com/pub/product/AlignmentSystems/4883T/software/training/4744T.pdf

Dog legging is what the lowrider/hydraulic crowd calls pulling up one of your rear wheels similar to a dog pissing on a fire hydrant.

The only references to "dog-legging" with regard to faulty suspension are right here on CK5.

And it matters because somebody who goes to an alignment shop and says "my car is dog-legging" is going to be looked at like they're a moron.

But anyway...

With regard to the issue at hand, maybe try pulling the front driveshaft to make sure you're not getting any bad juju through the drivetrain.

Have you tried lifting the rear end off the ground and putting it in gear to make sure both tires are turning?

One of the axles you swapped in might be bent or something crazy like that.

 

[1-ton]

WRONG. It is called "dog tracking" because of the way ANY dog runs. They run diagonally, so their hind legs are between their front legs for clearance

I do not care what you say. The whole idea of using the metaphor of a dog to describe a bad thrust angle was originaly because how a three legged dog runs down the road, and not how a dog normaly runs down a road. I don't think you have ever seen a three legged dog, which managed to survive being hit by a car and loosing their leg, run down a road. The term "dog legging" has been around since well before Autozone, and even Hunter Enginering existed. The term "dog legging" was an original term used by good-ol-boys. It was later altered to "dog tracking" by by engineer types, in order to use the metaphor for factory training, without sounding like some type of "local yokal".

 

[sandSStorm]

UPDATE!!!


Problem has been solved.


I scavanged a sway bar from another blazer i own and it fixed my problem. Its kinda weird tho, last year I removed the original sway bar and the truck ran fine. I wheeled w it all summer without any problems. When I swaped axles the problem started.

Thats all!

Thanx for your imput gentleman.

 

[chevyguybc]

was afraid i might have this problem too, im going to attach my swaybar after im done my 52s swap... gunna need to drop it down though

 

[BranndonC]

sounds like a locker to me too. My locker pulls a bit to the passanger side when i get on it say on the freeway, and when i let off it pulls right back to the drivers side (well this was in my old blazer, not my current jimmy)

 

[sandSStorm]

sounds like a locker to me too. My locker pulls a bit to the passanger side when i get on it say on the freeway, and when i let off it pulls right back to the drivers side (well this was in my old blazer, not my current jimmy)

I still feel some pull, but not as severe as before. I can actually live with it now...

 

[goldwing2000]

I do not care what you say.

"My mind is made up, don't confuse me with facts."


SandSStorm, glad you fixed it enough to live with it.