Sierra Gear Pinion Gear, Defects

[Black1990jeep]

Hi: I bought a Sierra Gear ring and pinion for my front diff, 4.1 ratio. I am concerned about the quality of the parts. I found all the splines on the pinion shaft to be heavily burred, with a big full length burr on one side of each and every spline, and the splines also appear to be too thin with this big burr rolled over the top of very spline, YIKES!

With this very poor machining of the splines, my yoke needs to be forced onto the shaft. This makes me question the entire quality of this brand, or maybe this is a rare instance? It is however pretty bad, how it passed inspection is beyond me.

I am in processes of returning this gear set. I am thinking to go with another brand. Is Sierra Gear some cheapo brand, not known for quality? what are the higher end brands?

I figure if they couldnt do a decent job of the splines, what else is wrong, poorly cut gears that wont mesh right? improper heat treatment etc.....

I dont want to risk a defective ring and pinion ruining my ARB diff, and causing me to redo all the install prematurely. I want my rebuild to last. Thus if Sierra Gear is a low end maker, I will want to upgrade to a better brand. I am new to this and learning a lot. there seems to be good quality parts and some really poor quality junk being sold as replacement parts so I have found on many other parts during my near total rebuild of major systems on my Jeep.

Any advice on gear brands to avoid, and brands that are stellar in quality?

I was hoping to have my diff finished today, but that is not happening.
Thanks!

 

[themauler]

I think I have motive gears and nitro gears in my diff. Still spinning after a lotttttt of miles.

 

[sidewaysstarion]

Even if the ring and pinion go, it's hard to damage an ARB. But either way, I'd go with a name brand like Nitro, G2 or Motive gear (All come from the same factory).

 

[Greenz]

I have Sierra Gears in mine. The shop that installed them have been building Jeeps for 40 years. So they say. They ended up replacing the front set of gears free of charge after they howled from the first they were install and got worse. The rear set is noisy too and the shop refuses to replace them. They said it was normal for 4:56 to have a little noise. I'm so pissed I cant see straight over that but it hasn't got worse. Should have bit the bullet and bought all the tooling to do it myself. Would have been cheaper and I would have no one to blame but myself if it didn't work out.


Can't say if it's Sierra Gear or the shop that is to blame. But I will say this, Sierra Gear is a 5 cut gear. Some say a 5 cut is stronger but I don't know that for fact. Gear mesh does have more surface area contact than the standard 2 cut gears most everyone else is selling. The old Yukon gears that made them known was 5 cut but they have since switched to 2 cut gears.

 

[WCD Eric]

My suggestion would be for you to contact Sierra Gear directly if you think there is an issue. Tell them what you see, send some pics.....The quality of the parts is guaranteed. (I work for West Coast Differentials, Sierra Gear and Axle is our brand) For those of you that have issues with noise, there are two reasons for it: Incorrect Setup or Improper Break-in.

 

[WCD Eric]

Update: I see that the OP has already contacted us via email. We'll get to the bottom of this for you ASAP.

 

[Greenz]

My suggestion would be for you to contact Sierra Gear directly if you think there is an issue. Tell them what you see, send some pics.....The quality of the parts is guaranteed. (I work for West Coast Differentials, Sierra Gear and Axle is our brand) For those of you that have issues with noise, there are two reasons for it: Incorrect Setup or Improper Break-in.

Thanks Eric. I downloaded SG's break in procedure and followed it to the letter. I'm leaning toward improper set up. My noise is only on acceleration. Goes quiet on decel. Shop refuses to even look at it. Can it be saved or is it ruined? Only about 1000 miles on the gears.

 

[WCD Eric]

Thanks Eric. I downloaded SG's break in procedure and followed it to the letter. I'm leaning toward improper set up. My noise is only on acceleration. Goes quiet on decel. Shop refuses to even look at it. Can it be saved or is it ruined? Only about 1000 miles on the gears.

Setup could be an issue. 9 times out of 10 it's gonna be setup or break-in that causes excessive gear noise. Once they're noisy you're pretty much gonna have to live with it or get it redone. Has the rear always been noisy? When is it noisy (accel, decel, cruising or...)?
One thing to keep in mind is that the mighty unibody XJ transmits noise like crazy. Any non-oem suspension components, especially heims amplify the noise. It's hard to get it perfect in cherokees, vans and vehicles like that....total echo chamber.
My 97 with an RE longarm kit, 33's and 4.56 gears was super noisy (got the gears in and drove straight to Moab from SoCal, no break-in.....duh!) Next set was broken in properly and was almost quiet, but not perfect......both gear sets were Midwest (Motive)

 

[Greenz]

Thanks for sharing your expertise. I did the lift before the gears and it was not noisy. Then after the gears were done it made the noise. Only noise is on accel. It's more of a sing. Coast it goes away completely. I did have an ARB installed at the same time. Also changed the oil after first 500 miles. It was black and so much metal on the magnet it was difficult to pull the drain plug. I put heavier weight lube in and that made it slightly more quiet.



Can you give any insight on the different gear cuts? like is there an advantage to one over the other?

 

[WCD Eric]

A little singing might be acceptable and sometimes goes away with mileage. Re: the gold panning (silver in this case) when you did the 500 mile oil change, a fair bit is pretty normal. If you are concerned about whether the gears are on their way to rapid failure, pop the cover and send us a pic of the gears. Most likely they're not or they would be howling like crazy.

Re: 2-Cut vs. 5-cut - 2-cut is faster/easier/cheaper to manufacture? Modern mfg. processes are moving in the 2-cut direction. Lots of speculation about strength...some claims that they should be "as strong".
Setup is a bit different. Some of the 2-cut gears we get from our source in Italy are quiet in applications that have been historically noisy.

 

[Greenz]

A little singing might be acceptable and sometimes goes away with mileage. Re: the gold panning (silver in this case) when you did the 500 mile oil change, a fair bit is pretty normal. If you are concerned about whether the gears are on their way to rapid failure, pop the cover and send us a pic of the gears. Most likely they're not or they would be howling like crazy.

Re: 2-Cut vs. 5-cut - 2-cut is faster/easier/cheaper to manufacture? Modern mfg. processes are moving in the 2-cut direction. Lots of speculation about strength...some claims that they should be "as strong".
Setup is a bit different. Some of the 2-cut gears we get from our source in Italy are quiet in applications that have been historically noisy.

Good to know. I will try to think about it more positive until proven otherwise. I hear so many folks out there say things like, it shouldn't make any noise. To me it sounds like an old farm truck so maybe its normal like the shop said.



I'll try to pop the cover off in the next few days and take a look. Out of town right now.

 

[Black1990jeep]

Update..

The gear set was exchanged with no problem, The replacement set is much improved, and is being set up in my differential now. The vendor tells me they have sold many many 100's of these brand sets and this is the first problem like this, The vendor checked all the remaining gear sets in stock and did not find any other bad splines. Stuff happens, but its good now. The vendor sent me a new set of ring gear bolts to replace the ones I had already torqued. Thumbs up to West Coast Differentials, excellent and rapid customer service!

Now the fun of reassembly.
Thanks!