I'm not sure what is wrong but it suddenly felt like it was under braking when I was on the highway, then started smoking from somewhere, so I pulled off the highway to look at it and it is idling fine and not smoking...If I rev it only the normal amount of smoke comes out the tail pipe. It dose smell a little bit strange...Also the po cut the cats out for some reason.....and did the worst job of rewelding I have ever seen....so now I'm stuck on the side of the road.

 

Brake(s) hot?

 

I didn't see any bluing on the rears and can't tell on the fronts

 

Are you saying that your car won't move in drive? Or it will move but you have no brakes? The previous owner probably took the cats out to run a straight pipe setup which some ppl do when the modify the exhaust system but i don't see why that would affect your brakes. What year LS do you have/

 

The car drives, but I'm about 30mith from my house and if it is the brakes I don't want to drive it that far and I don't have aaa, I'm sorry I wasn't clear about the year it's a 1990. I did the rear brakes last week, so the pads and rotors plus the drivers caliper are brand new. Also I think the po put the wrong size rotors on the fronts since they are smaller than the rears...which dosent make any sense to me....I work at a car ship and ordered the proper rear rotors and I can see more of them through the cutouts in the rim compared to the fronts...

 

Do the brakes work at all? Your only option is to call a tow truck if your not willing to put your hazards on and stay in the right lane. Is your brake light on in the dash?

 

Brakes do work and no dash light

 

Sorry for the delayed responses but I'm looking up other info while responding to you. If the brakes are working then take your time in the slow lane with your hazards on for the 30 miles if your worried.

 

No problem on the delayed response, I called aaa and they should be here soon, I'm going to take a look at the brakes when I get home, the worst part of the is I have had to pee for about 3 hours now and there is not a place for me to do so

 

Ok so I think I found the issue, the front diff seal is leaking fluid, a 6 or 7in wide puddle In a matter of 30min or so, is this a common problem for the ucf10?

 

Is the funny smell 90w gear oil?
Do you suspect the differential is failing and causing the drag?
I have not heard of troubles with the UFC10 rear end. I do beieve that Toyota reccomends chaning that oil more frequently than other MFGs.
I do hope you were able to pee.

 

front diff seal can go on LS400, but usually only on cars with really high mileage or else salt roads in winter, are either of those you?

if rear end oil were to get on the tailpipe or muffler or resonator, it would definitely make lots of smoke!

 

If you emptied the diff of fluid, you could have begun to seize the diff... This would explain the dragging sensation you felt, and could also explain the smoke either from the diff itself or from the fluid splashing onto a hot exhaust.

 

^^^ This sounds like a plausible explanation.