I just finished rebuilding the rear-end of my Dakota and I'm getting a howling during deceleration. I know that it's probably the front pinion gear since I know for sure that my backlash is .005/.006, but I'm thinking that my torque wrench must be out of calibration and I'm not pre-loaded enough. The pinion doesn't spin freely, it has pre-load on it, but is doesn't need a lot of muscle to spin. Should it feel tight, to the point you need some muscle? Good engineering terms, right...lol. Also, I have a new in.lbs torque wrench on order...... Thanks for any feedback.


Scooter_SLT

 

What gear set did you buy I know the cheap set can give you just what you are talking about.

I looked into changing my rear-end with a new set and noticed many were stating they are quiet and others didn’t say that at all.

The cheap gear sets can cause noise.

 

I bought a motive gear set from Summit Racing. The set looked a lot better than the stock one. All the bearings and races were National brand. I'm not getting any noise gasing it, just when I let off. I gave the pinion nut a little tweak tonight and the noise changed a little. I might just have a bad outside pinion bearing.

 

Well my understanding is that national is the cheap noisy set you want Yukon or Nitro for the quiet set they are way more expensive but that’s why.

The noise could just be it needs time to wear in that’s a possibility the gear sets being noisy is just what I have read not from experience so I may be wrong.

But any time you buy cheap there is always a reason they are cheap.

Summit is not a cheap place from what I see.

 

Loose pinion nut will cause what you are describing. What all did you replace and what is original?

 

New bearings, races, ring and pinion set, wheel bearings, crush sleeve, and pinion nut. Original yoke mount, carrier, and axles. I broke it down, sandblasted and powder coated (outside only), cleaned inside throughly like it was going on the space shuttle. Installed everything using a little lithium grease. Had a little trouble getting the crush sleeve to compress, didn't have enough leverage to muscle, but got it. Should I give the pinion nut a little more to compress the bearings to be tighter? Or should I give it a chance to break in since i'm only 50 miles into breaking it in? I was thinking of taking out the outside pinion bearing and inspecting, but not sure I have the tools to remove without tearing everything down again. Have to check and see if my slide hammer can grab that bearing.

The Motive gears, in my opinion, were quality gears, especially the pinion. The stock bearings were Timken and I did side-by-side measurements with the Nationals to check for any differences "with calipers" and didn't find any issues. I couldn't tell you what the material hardnesses between the two would be since I didn't throw them the rockwell to findout. I didn't like Nationals wheel bearing seals. They don't have a lip to stop at the edge of the housing.

Thanks again for any suggestions.

 

I've always heard mixed reviews on break in time for gears. Some say its not needed others say you should. One thing I do know though if you have a noise after install you will always have a noise. Im thinking they are not mashing right. Im assuming you have done gears before to know what you are doing.

 

Thanks, I was thinking the same thing, but it's so quiet when on the gas. Looks like I'm tearing it down this weekend.

Week Later, well, I rebuilt the rebuild and I still have the howling. I could see that I had to much pre-load on the bearings and races. I used the same brand of bearings again. If I ever get a chance to go at it again, I'll probably try a diffrerent bearing brand to see if there will be a difference. I have read in my research that this style of differential is prone to this and my experience to putting in the races would agree that it does resinate sounds through the entire housing very well. I thought I was ringing the liberty bell or something. Anyway, I would suggest not using national bearings on the pinion gear if possible.

Please don't hesitate to ask me any questions about my experience or advise with the rebuild. I'll post pic's soon. Thanks for the advise and I hope this helps someone else.

 

Scooter, Can you post a picture of you pattern after the gear was setup? I can tell a lot about the setup from seeing where the pattern is centered. If the depth is off, or the B/L is incorrect it will be noisy. What was your pinion preload and carrier preload? The carrier needs to have 150-200ft lbs. of preload on the threaded adjusters. When you took it back apart had anything changed? Preload, Backlash, or pattern? Did the gear have any runout, ( check the backlash in 4 places around the ring gear to ensure there isn't runout or material trapped between the case and the gear.) Let me know if I can help in any way.

 

I don't have a picture of the pattern, but it was ok. I made sure of that and the backlash measurement was .006 and that was checked in 4 areas. I put a pre-load on the pinion of 15 in lbs. It was recommended to be between 10-20 in lbs. as for the carrier adjusters, I didn't find that specification, but I used 20 in lbs like the pinion. 150-200 ft lbs seems extreme. You are talking about the threaded rings with the slots around it face?