Need Automotive Help? Ask away... - Buy & Sell Car Audio Equipment

Piston · 04-13-2007, 02:29 AM

I'd like to offer my services (online Q&A of course) to anyone here that needs help. I've been in Auto repair for just over 17yrs and do repair/diagnostics on any make/model.

So whether its a mechanical problem your not sure about, general repair questions, need a Service engine Light code definition or Wiring schematic help for whatever... just ask away and I'll do my best to help you.

Keep in mind this is black/white text and very hard to diagnose over the internet

So if your having a drivability problem, pleast be as detailed as you can be when describing the problem.

Piston · 04-13-2007, 03:11 AM

Haven't seen much of that. 2wd or 4wd? Should be a torsion bar adjustment that can level out your ride height in the front. Some 2wd's (depending on what year) went back to a coil spring.

Shoot me some specifics on year/model/engine size and I'll do a TSB search in the morning.

Piston · 04-13-2007, 03:19 AM

Trouble with spacers is they change the spring compression rate, doubtful it would ever be noticed on daily driving but its a sign that the spring is slowly collapsing.

Piston · 04-13-2007, 03:30 AM

Have them run a search for TSB's and recalls for your vin and go from there.
With it being someone new (within the last 2-3 years) I haven't had any customers complaining of that "yet". I did a search on IATN but nothing came back about the problem. I'd bet its just weak metal used.
I highly doubt its another componant, unless you have a binding rear leaf shackle causing it to push down on the left front but I've only seen that on one vehicle years ago.

Best bet is to do what your doing... replace those springs.

1loudsuv · 04-13-2007, 03:34 AM

wow 17 years and i thought i had experience i worked for a mechanic shop for 6 years and still work for them on and off when they are needing help especially in diagnostic's with obd 2 and anti lock systems, or when they want something high performance. so if anyone wants any help you can pm me to im sure the op knows more then i do but having two sources is better then 1

Piston · 04-13-2007, 04:00 AM

Thanks for the help

It definatly helps having more than one source!

dyabolical · 04-13-2007, 04:32 AM

I have a 1997 Z71 extended cab chevy. 220k miles.

I purchased the truck, drove it for a few weeks and noticed that i had a persistant whining noise. I was driving down the road when all of a sudden my truck makes this huge crack sound and my truck will no longer roll. We decide the rear end blew up so we haul it back to the shop. Me and my dad replace the rear end gearing...pinion and such. We notice it leaks fluid out of the yoke where it connects to the drive shaft...i tighten the big nut down and the leak stops.

But now i have a really obnoxious whine noise while i drive...we have actually never been able to get it to go away.

When i am driving, if i let my foot of the gas and coast, the whine will go away, but as soon as i put my foot back on the gas it comes back.

Also, while i am driving...if i am on the gas and drop into neautral...the whine goes away...i am still on the gas by the way. When i go back into drive while on the gas the whine comes back.

I am having a horrible time figuring out if it is the trans or the rear end....i am thinking the rear end might not be shimmed right?

Any help would be awesome.

oxsign · 04-13-2007, 05:07 AM

This seems to be a "normal" occurance with chevy trucks in general. It's known as "the chevy lean", LOL. All of my s10/blazers did it, and well as my boss' silverado. They sell a "shim" if you plan on keeping the front coils. It's about 1/2" to raise the driver side, and it sites under the coil itself. Or you can use spacers in between the coils that can be bought at any auto place (autozone, pepboys, etc). The last fix if a 1/2" space plate put between the axle & leaf spring. Heres a good read about it on a full size.
http://www.fullsizechevy.com/forums/...d.php?t=209149

dyabolical · 04-13-2007, 05:08 AM

Piston · 04-13-2007, 05:10 AM

When the rear end was built, did he use all new bearings? or just replace the gears?
You need to double check the backlash adjustment. If the gears are setup too tight or too loose you will have a whine or hum from the differential on accel and decel while being quiet on coast, meaning the bearings are most likely good, you just have a mesh problem.

You mentioned tighting the pinion nut down, be careful there... thats a precise adjustment for bearing preload and could damage the pinion bearing if tightened too tight. For instance, it takes an average of 140ft/lb's to turn the nut but you only want 18-25in/lb's of resistance on the pinion rotation (a bit over technical I know).

The things that should have been checked when building the differential are:
Pinion bearing preload, Pinion depth, Carrier bearing preload, gear mess or contact area and backlash. If all of these were not done, that will explain the noise and you'll need to go back in, replace the crush sleeve and adjust everything out again.

Hope that helps and is not too technical, if it is don't hesitate to ask for a better explaination lol.