Hi,
I tackled the timing belt on my 98 4Runner 3.4 with 130K today. It's not too bad with the right tools and all the writeups here
But I do have a major concern;

1)what caused the key hole to wear funny?
the key appears to be fine and the crankshaft isn't scored.
2)is that crack a major problem (I think it is) That crack goes all the way
along the top to the belt guide. I used a puller to remove it and it did not
come off easily. Nor does it slide back on easily.

I'd like to fix whatever is wrong while I have it apart.
As always, THANKS!!

 

yes, that is very bad.

It comes from an improperly tightened bolt, which allows the pulley to rock back and forth. Very common on the 3.4's

Replace that balancer ASAP, anything that is cracked is a MAJOR problem

 

Thanks for the info! I've been online looking, so far I've found an OEM one for $294.

 

What DC said. It cracked that way because very little of the key on the crank goes into the pulley--just that little square that is widened out. It is the bolt torque that fixes the pulley. It is spec'ed at 218 ft-lbs on later 4Runners, a little less on earlier ones. You are lucky you caught it early, this could have gotten much worse and ruined your crankshaft. Swap the balancer and torque to spec and you should be fine.

 

I went through 2 of these myself. The first repair, the DEALER even failed to replace it properly, and the second pulley was destroyed, and I mean, not even a key slot left destoryed, before 5k miles... With the price of a new pulley, I would either find a junk yard pulley in good condition or try to find a URD pulley.... There are still a few of those floating around that are in new condition.

I would also recommend replacing the woodruff key - mine was sheared in two, and I could not tell until I took it out to inspect it.

And yes - make sure the bolt is torque'd properly. Some shops tend to just hit it with a big air impact driver and 'call it good'. That's not good...

 

Good point on the woodruff key. I'll grab one of those as well. I'm guessing that just slides out. I'm glad to find this out at home vs on the road somewhere.
Thanks!