Expert: Dan Liddy - 2/29/2008

Question
Mr. Liddy
I recently purchased a used ACT Late Model race car for my son to race at our local track. I noticed when pushing the car backwards into the garage car in neutral that the rear end makes a clanking noise upon backing the rear end is locked my question is this normal or should I be concerned that the rear end is blown? If it is where or what do I check? Thank you for your time and expertise.

Answer
Hi there !  

Wow !!  MR. Liddy !?! - - - That's what they called my grandfather !!  

The clunking rear end is normal for a locked rear and some posi-traction units.

I have one called a Detroit Locker, that is a ratcheting type and in a corner it makes the most un godly noise you can imagine. First time I nearly jumped out of the car !!  (I'm a road racer so we turn in both directions and sometimes the corners are seperated by long straightaways).  

If you have a real welded locker, when you push it forward and turn a little at the same time, one of the rear tires will chirp ocasionally too- - - they're weird !

To check it for sure, jack it up so both rear tires are off the ground, then turn one wheel with your hands (or his !!) .  Both rear wheels should turn at the same time, and with very little noise.

Then set it down, and re-jack it so only one wheel is off the ground.  It should be impossible to turn the free wheel at this point .

Change the oil in it to one of the synthetic gear oils. Valvoline makes a good one that's reasonable in cost.  Be sure you get it full.


I hope this is a help - - - let me know if you need other info !!

Thanks for writing

Dan Liddy
Sarasota, Fla.