How to: 4.10 install and differential overhaul
Thread Starter
Joined: Sep 2009
Posts: 41
From: TX
I edited the backlash specs. Got the info from this website under step 12: http://www.fordracingparts.com/downl...And-Pinion.pdf
4th Gear Member
Joined: Dec 2010
Posts: 1,597
From: Gallifrey
I have more traffic tickets then the years of my age.Judging from this though, he´s probably a lot more mature about it then I would have been. Or more than likely, even now.
I´d have to ask the guy´s at Swarr auto what mine was set to, as I´ve haven´t the foggiest. With 4.10´s I notice no whine, though they did say depending on how it left the factory would be more the cause to it once they were done, as I think it was the camber they mentioned being one of the deciding factors. That and how well I´d baby it for the first few cool-down/heat cycles til it was all worn in.
I did my best to lay off for the first 2-3, seems to have paid off, as I don´t notice anything besides the added power. Well, and the constant need to shift gears, which I actually consider a bonus for me personally. Had it installed now about 2 weeks and this is my only car/daily driver.
Last edited by wayne613; Dec 24, 2010 at 02:50 PM.
2nd Gear Member
Joined: Nov 2008
Posts: 199
From: texas
I was wrong on the suggested backlash. Looking at the FRPP website, they say backlash is to be between .008" and .012". I'm not sure about your gearset but I'm sure that your fine. The motive gears may be different in terms of backlash spec, but I'm saying that from a completely uninformed perspective and to be honest it doesn't really even make any sense why that would be true.
My backlash ended up at 0.011" which is in spec but it is on the loose side when I look at Ford's site. But it's worked out for me so far. As a bit of a story when I was taking everything apart, I couldn't even get a backlash reading from the factory setup because there was absolutely no pinion bearing preload so if I wiggled the ring gear at all, the pinion turned, so backlash wasn't even measurable. I don't know why I brought it up, but I thought it was interesting. If I had to guess I would say that the backlash was way too loose from the factory.
If someone knows for sure than say so, but I would think that the tighter the backlash, the more likely you are to have whine. does that seem to make sense to anyone else? Brunobluto, did you have an increase in whine after you did your install? Because I have a little bit louder coast, but the drive side is silent. I ask only to see if backlash makes a difference in whine.
My backlash ended up at 0.011" which is in spec but it is on the loose side when I look at Ford's site. But it's worked out for me so far. As a bit of a story when I was taking everything apart, I couldn't even get a backlash reading from the factory setup because there was absolutely no pinion bearing preload so if I wiggled the ring gear at all, the pinion turned, so backlash wasn't even measurable. I don't know why I brought it up, but I thought it was interesting. If I had to guess I would say that the backlash was way too loose from the factory.
If someone knows for sure than say so, but I would think that the tighter the backlash, the more likely you are to have whine. does that seem to make sense to anyone else? Brunobluto, did you have an increase in whine after you did your install? Because I have a little bit louder coast, but the drive side is silent. I ask only to see if backlash makes a difference in whine.
Thread Starter
Joined: Sep 2009
Posts: 41
From: TX
I also have a little whine on coast, but pretty quiet on drive side. From my experience, I think improper pinion depth and pinion bearing pre-load causes the majority of whine people have after installing gears. I thought my factory gearset was too loose also, but it was quiet. Getting the pinion depth and bearing preload right can be difficult and is where most gear install mistakes are made, IMO.
I found pinion depth pretty tricky from a standpoint of it's completely qualitative without the official and very expensive pinion depth tools. It's not like backlash or anything where there is a very specific specification and you have a definite measurement from a relatively inexpensive tool. I scrutinized wear pattern as best I could, but ultimately I was just hoping for the best.
I´d have to ask the guy´s at Swarr auto what mine was set to, as I´ve haven´t the foggiest. With 4.10´s I notice no whine, though they did say depending on how it left the factory would be more the cause to it once they were done, as I think it was the camber they mentioned being one of the deciding factors. That and how well I´d baby it for the first few cool-down/heat cycles til it was all worn in.
I did my best to lay off for the first 2-3, seems to have paid off, as I don´t notice anything besides the added power. Well, and the constant need to shift gears, which I actually consider a bonus for me personally. Had it installed now about 2 weeks and this is my only car/daily driver.
I did my best to lay off for the first 2-3, seems to have paid off, as I don´t notice anything besides the added power. Well, and the constant need to shift gears, which I actually consider a bonus for me personally. Had it installed now about 2 weeks and this is my only car/daily driver.
5th Gear Member
Joined: Jul 2006
Posts: 4,491
From: New Orleans
Fantastic. You have the attention to detail and work ethic that make me believe you are mature enough at your age for a car with that much power. At this point, you're the only person I've ever said that about. On a side note, that old GM video is a fantastic explanation of how a differential works for anyone out there who doesn't already know.