I was just wondering if its ok to run thicker gear oil in my 7.5 ten bolt. I just had 373 gears installed maybe two months ago, maybe you remember, i put used gears in and they whinned like a S.O.B. so i took in to a shop and put new summit gears, they replaced the bearings and seals and said everything was very good, but they still have a slight whine to them, they said it could be the new gears the way the teeth are cut they whine during the "break in period" after 500 miles to change the oil and metal shavings should come out and it should be fine... But idk maybe they just told me that to shut me up. lol. So question is would running 75-140 royal purple be ok??? I know it call for 80-90 weight, but since i live in south texas where its hot as purgatory most the year thought of running a lil thicker gear oil. Thank you

 

75-140 includes 80-90 weight so it should cause no problems, but I doubt it is going to quiet down the gears. I am not saying that this is the cause of the noise, but gears designed for racing are sometimes made of harder steel than factory gears, and sometimes cut at different angles to improve strength. All which can make them noisier even if accurately set.

 

Oh ok, yeah the guy kept damming the gears that i should have bought they're gears they sell and stuff. Have you heard anything bad about Summit racing products???? I bought them cuz it was a good deal lol.

 

Nothing is wrong with Summit...what is wrong is that gears are difficult to put in and get right. When I have replaced gears in the past, they have had a slight whine. That seems to be the nature of the beast. You have to set bearing preload and you have to put the appropriate pressure on the crush sleeve and you have to shim the carrier and pinion in just right so that they meet at the proper angle. The carrier can be shimmed right or left and the pinion in and out. It is a balancing act that takes me sometimes 6 hours to get right. The gear doesnt really matter, just make sure that if you have have a limited slip diff-you run the additive for it, for the clutches.

 

I didnt think so, just stating what they told me. Yeah they had my car for a whole week, dropped it off monday didnt get it back till the following monday. The mechanic told me he kept having to re shim it and stuff. Idk if he even used the additive, i had all the parts oil and all, and when i got the car back it was still in the back. So yeah, still gotta change the oil maybe i'll do that tomorrow if i have time. But it drives fine just has a slight whine to it.

 

How's the condition now? Did you change it?

 

let us know how shes running and if it worked good.

 

She's running fine still nothing out of the ordinary, I still have not made the time to change the gear oil the wife has been keeping me pretty busy just found out we're having a little girl so as soon as im home she's got me doing something if not shopping. I have to work late today i think its the perfect opportunity to put her on the lift and do that today... Hopefully its dead later this evening. Thanx for all the replies fellas.