I installed a set of Richmond 3.90 gears in my '89 Toyota 2WD, along with a Detroit TruTrac. I used a Yukon install kit with Koyo and Timken bearings. Pinion shimmed to get proper pattern as shown on Richmond instruction sheet, backlash adjusted to .008", checked with Starrett dial indicator. Pinion bearings and carrier bearings preload set according to instructions. Running Mobil 1 75W90 gear oil.

Upon assembly, I filled the differential with oil and ran it for 10 miles up on blocks at a fast idle speed, with transmission in 5th gear. Then removed the blocks and let it cool down for 1/2 hour. Then a short drive, 5 or 6 miles, at 40 mph, parked it for the night. Drove 7 miles to work the next day at 45 mph or so, and home again, repeat for 200 miles. Initially differential case would get pretty warm, but gradually less so.

At 200 miles I changed the differential oil, it was very dark, and replaced with more Mobil 1 75W90. Now 600 miles since gear install, and 400 miles since oil change, checked oil today, nice golden color, essentially looks like new oil. I can drive to work in the morning when the air is 75 degrees or so, at 60 mph or more, and check differential case, not warm enough to cause discomfort, perhaps 120 degrees? Certainly less than hot water from the showerhead. Driving home during the heat of the afternoon, (95+ degrees), case seems significantly hotter, but in the afternoon everything under the truck is hot, the driveshaft, the frame, crossmembers, so I'm thinking that everything is picking up heat from the road as well as generating some of its own heat.

However, the gears have always made a high pitched "singing" or whine which fades in and out at different speeds, when accelerating, around 28-30, 45, and 60 mph. It isn't LOUD, and it was somewhat louder 600 miles ago than at present, but it is audible, and somewhat annoying, as the old factory gears were completely silent at any speed. The fact that the sound is louder at certain speeds makes me think it is some kind of harmonic vibration which coincides with certain speeds of rotation, i.e. the teeth meet each other at a certain frequency and generate this sound.

My question is: Is this a characteristic of aftermarket gears in general, or Richmond gears in particular? Is 600 miles not enough time to wear them in?
Did I perhaps goof up something in the installation process? Or would perhaps using thicker oil, say, 90W140, quieten these gears?

Any ideas?

 

I've heard that Richmond gears are very strong(strongest according to many), yet a bit noisy. I think your probably fine, don't know about the thicker oil though. Might be helpfull.

 

Since you used synthetic oil for the standard breakin period, they probably aren't broken in yet. Dino oil is usually preferred for breaking for this reason.

Be sure to PM "Zuk" with a link to this thread - he's the gear install master on here...

 

Hi ron521---
Got your email....what you are experiencing is "normal" for a Richmond. Just run it.
As you probably noticed when you set them up that the drive side favored the toe end pretty heavy....a typical "competition pattern" and very typical of Richmond but they tend to whistle because of that. I guess Richmond thinks everybody drives a race car!
Also, ALL Richmond want to see .010" for a backlash value....it's even scribed on all of their ring gears. .008" is close enough I bet. The whistle may go away with time. I just don't know how much time ZUK

ps----not my favorite gear for sure....I have installed numerous gear brands in the past.....only 2 sets of gears I have done had to be returned due to thread defects.....and both were Richmond. Most of them are good I bet....they just don't have enough trained folks in the threading department ZUK

 

Thanks for your replies, everyone.
Glad to learn that the sounds I'm hearing are not a sign of some problem.
ZUK, funny you should mention the threading issue as something common to Richmond. When I installed the ring gear and torqued the bolts from the Yukon install kit, two of them wouldn't tighten up, just kept turning at 55-60 ft/lbs. When I removed the bolts I found that they had peeled their threads off, although the ring gear threads appeared perfect. So I removed ALL the Yukon bolts, assuming something was wrong with either their heat treating or diameter, and installed the used OEM Toyota bolts, which all tightened up properly to 75 ft/lbs. I used blue Loctite and the factory lock tabs as double insurance (although if the threads in the ring gear DO let go, I'm not sure either would actually help). However, I tend to think that if the ring gear threads were messed up, they wouldn't have taken full torque of the factory bolts.