AlphaCrow

Hi again. I posted about my '00 blazer running rough:
http://www.automotiveforums.com/vbul...01#post5737901

but I've figured out its the transmission after all. I caught it idling rough and put it in neutral and it cleared up the idle issue. A day later, the sun gear shell apparently sheared again as I accelerated, taking out 2nd, 4th and reverse.

I had this exact same issue before. I found out there was a TSB about a faulty sun gear shell (thanks chevy). I had the shell replaced and tranny rebuilt.

Now, its still under warranty, but why would it possibly go out again? I am far from throwing it in reverse to drive or vice versa. Very careful about stopping before switching gears. I don't drive my blazer hard at all.
Any ideas why it would possibly go out again? The first was a poorly heat treated metal (iirc), but a stronger one broke also in under 2 years?

blazes9395

This, as I am sure you already know, was a big problem for GM. What type of sunshell was used for the rebuild? The GM revised sunshells are not that much better than the previous ones they were using. The aftermarket did solve this problem, with ones such as "the Beast", stronger and more durable, but now I notice all of it is now being made overseas(China/Taiwan) and I am questioning the quality again.

I still though use "the beast" sunshells in any rebuild I happen to do. At least your under warrenty, so it won't be as bad....

ken_man_1

YES YES YES YES YES!! The Beast. They put that thing in dragsters. Do yourself a favor - BUY IT and have the rebuild techs use it. I put over 50K on my trand since I rebuilt it and no issues. It only makes sense - if you're planning on keeping the vehicle for years to come - to use the BEAST.

AlphaCrow

Thanks for the beast advice. My first tranny rebuild was luckily done at a good quality father/son shop. They gave a 2 year warranty and when I brought it in, were more than willing to honor their word.

The mechanic says the china one is actually pretty good, but when I asked about upgrade, he knew about the beast and I paid the $50 difference for it to be installed this time.

BTW, both of them are amatuer drag racers, I wonder if that's why they do transmissions on the side.

AlphaCrow

I had the beast shell installed, runs smoother than before, but I hear more road noise, perhaps coming from the tranny. Does that sound like a possibility for the sun gear shell causing this?

MT-2500

No.
The new sun shell should be quieter,
Tires and wheel bearings or rear ends are the main road noise makers.
Or you may be listing more since the transmission repair.
Can you describe the noise?
Does it change with MPH or more in any one gear?

__________________
Remember proper testing gives us the answer to many problems.
MT

AlphaCrow

Along the lines of a humming noise, associated with MPH. The car shifts smoother.

MT-2500

The same noise in all gears?
Does the noise change going down the road 35-45 MPH when you turn the steering wheel a little to the left or right.

Some tires have road noise.
Check for smoth tread or cupped thread.
MT

__________________
Remember proper testing gives us the answer to many problems.
MT

AlphaCrow

Seems to become slightly higher frequency as I speed up, but fairly stable noise. Could be the tires, but they are fairly new and quiet. I only noticed it after the tranny fix.

I check the tires and listen carefully at that speed when I turn and report back.

Thanks

MT-2500

You are welcome .
You might get the transmission repair place to listen tio it.
Good luck and let us know how it goes.
MT

__________________
Remember proper testing gives us the answer to many problems.
MT

AlphaCrow

No change at 35-45 with steering wheel movement. It may be that it is the tires, but they're new and have been quiet before tranny fix. Passengers have noticed the noise also. Starts at about 20mph and gets loudest 45-60mph, then will become quieter if going any faster than 60.

If someone told me about this, I would guess tire road noise. Just seems unlikely in this case, but all fingers seem to point to it.

MT-2500

Does he noise change in different gears?

Here is a link to rear end noise .
http://www.differentials.com/install.html

Good luck and let us know how it goes.
MT

__________________
Remember proper testing gives us the answer to many problems.
MT

AlphaCrow

Doesn't change in different gears. Whatever is causing it, its linked to MPH, it appears. I can hear the tire noise as a separate sound.

This is a heavier hum, vibration. Sounds crazy, but I can feel a slight vibration that matches the sound.

Doesn't sound like too many of those issues on that website. Its not just in a set gear range. Could it be something in the differential or U-joint? Would they have adjusted any of those other than flush to change out a sun shell?

MT-2500

I would go over all wheel bearings and transmission and engine mounts good.

Also check for fan blade-fan clutch,water pump,alternator or even ps steering noise.

Transmission sun gear or planatary gear noise should change with different gear.
But I would have the transmission man look at it and see what he thinks.
Good luck
And let us know how it goes.
MT

__________________
Remember proper testing gives us the answer to many problems.
MT

wafrederick

"The Beast" sunshells do break too and I know of one transmission shop that finds this.The teeth also strip out once a while and I have seen this.