Sun gear shell broken... again

Hi again. I posted about my '00 blazer running rough:
http://www.automotiveforums.com/vbulletin/showthread.php?p=5737901#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?

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....

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....

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.

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.

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?

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?

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

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

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

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

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

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.

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

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?

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

"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.

"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.

I haven't seen them split/torn at the hub, but I've seen them stripped. The China "Beast" will strip. The TranStar (Cleveland, Ohio) sun shells do not, and the thicker end of the shell should not twist out. You'll pay about $40 for a stock replacement, about $50 for a "Beast" forged of the finest Chinesium, and about $85 for the TranStar sun shell. However, after doing the math, the TranStar shell is a lot cheaper. The original shell in my Astro lasted 61K. The second shell (imported "Beast") in my Astro lasted 40,000 miles and two years. The one I installed two months ago is the TranStar A74624A. I've installed those in 700-R4s and 4L60s behind some fairly stout engines and they've lasted for hundreds of runs at the track, plus daily driving.

I have one more Asian "Beast" in my parts stock, and that will be the LAST one. I'd give it to you, but I don't want anyone upset. Really, you don't want it unless you're desperate and don't plan on keeping the truck for more than 30K miles.

As for the noise, make sure the drive shafts are installed correctly. The front one is flanged and should have been matchmarked for balance upon disassembly so it could be assembled in the same orientation. Verify the transfer case is filled, mounted squarely to the trans tail housing adapter, and is mounted on the crossmember. As previously advised, torque converter, pump, and everything in the transmission ahead of the 3-4 (input end) clutch should vary depending upon engine RPM, not road speed. If the noise doesn't vary between 1st or 2nd and the rest of the ranges, there shouldn't be a real problem. The front (input) planetary will vary between D and OD, so that really only leaves the low-reverse (rear) clutch stack and output bushing. I'm guessing the noise is external to the trans.

I just figured out it goes away momentarily when I make a left hand turn or curve going 30mph+. And when I hit a bump that lifts the blazer up a bit.

Someone mentioned about the turning and 30-40 mph. What causes that?

Thanks

I just figured out it goes away momentarily when I make a left hand turn or curve going 30mph+. And when I hit a bump that lifts the blazer up a bit.

Someone mentioned about the turning and 30-40 mph. What causes that?

Thanks

Read post no 8.

Thanks. Sorry about the extra posts. Just so dang odd that prior to tranny work, no noise. Instantly on pick up, loud noise. Even passengers notice it that ride with me often.

You are welcome.
Have you found it for sure yet?
Or got it fixed?
MT

Sigh, same thing

Hi again. Had tires criss-crossed rotated (they're marked, know they were done) a few days ago.

Noise is exactly the same. Goes away when turning left or when hitting bump that car is light on the wheels.

Noise starts as loud, deep hum and gets louder with MPH. Goes through all speeds, does not change with gears.

I suppose it could still be the tires, though I see no cupping and they're still very, very new. Plus they were dead quiet before.

Asked tranny shop about it, they have no clue what is causing it, off hand.

Could it be a bearing issue? Just seems unlikely to be a tire wear.

Hi again. Had tires criss-crossed rotated (they're marked, know they were done) a few days ago.

Noise is exactly the same. Goes away when turning left or when hitting bump that car is light on the wheels.

Noise starts as loud, deep hum and gets louder with MPH. Goes through all speeds, does not change with gears.

I suppose it could still be the tires, though I see no cupping and they're still very, very new. Plus they were dead quiet before.

Asked tranny shop about it, they have no clue what is causing it, off hand.

Could it be a bearing issue? Just seems unlikely to be a tire wear.


If noise changes on turning check wheel bearings.