Diagnosis help needed - sharp intermittent pull through steering

[derekb41]

On the road home from Yellowstone last night, I noticed a slight vibration through the drivetrain while accelerating 45-55 mph for a moment. A little ways down the highway, there was a quick momentary pull on the steering (moving the steering wheel ~ 1 inch) this pull felt mechanical - not a gentle tug by a bump or pull due to misalignment. this happened intermittently over the next few miles, so I pulled into the emergency lane and proceeded at 20-30 mph, at which the intermittent condition occurred at least a few more times over a mile or two. Again, this was a strong pull that was fast and recurred intermittently.

Edit: this occurred while traveling straight down the interstate, not during a turn/curve, and not during braking. Also, it had been raining heavy for the last few hours prior to this happening.

I am probably not giving enough detail for a thorough evaluation, but any suggestions on what to look for? I can wrench but have limited tools with me. My concern beyond mechanical was the possibility of this becoming much bigger at speed and causing a loss of control.

I did a quick visual of the upper/lower control arms, axels, rotors, tie rods and steering rack and did not see anything that looked out of the ordinary.

Its a 98 with rear locker and I am towing a camper. What are the symptoms of the dreaded exploded front diff? Could an exploded front diff produce similar symptoms?

Thanks in advance.

 

[Mike6158]

When my 2000 LC did that to me the problem ended up being a bad rack and pinion as well as bushings. The first symptom was the cruise control would kick off in a curve but only if I was turning right (I think. It's been a year or two since I changed my rack). Eventually the traction control system started braking one wheel for me. It was not a gentle braking action. It felt like I had slammed on the brakes but only one wheel was working. It only lasted for a second or two at the most but damn... it was very unnerving. I still think about it every time I round the curve at Silverton coming from Ouray. That was the third or fourth time it had done it (while coming down the mountain) and I was a ball of nerves. I still remember seeing a puddle of water in the road and wondering if it was going to brake when I hit it. It did.

I was able to find a carwash in Durango, clean the snow and mud off of the undercarriage (focusing on the area of the speed sensor) and that temporarily stopped the braking but not he cruise control kicking off. I drove the LC for another year before I changed the rack.