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I have been having a hard time getting my truck back on the road. I have a 91 f150 4x4 with a 4.9. It is an 8.8 rear with 3.08 gears. I had a leak from the right rear axle seal that I didn't know about which starved the diff for oil and caused all sorts of havoc. The ring gear and pinion gear were both razor sharp. The biggest issue I discovered is that the left side carrier bearing had spun on the carrier. I went to the junkyard and got a new carrier with the gears and bearings. I swapped everything into my housing and everything seems good until I snug the left side cap. As soon as I snug up the cap on the left side the diff locks up and will not turn. If I loosen the cap, it turns free as can be. I really need to get my truck back on the road. Any ideas would be greatly appreciated.
I'm guessing you replace the r&p and just slapped it in there? If you did or didn't doesn't matter at this point as you changed the carrier, whenever you go digging into a diff you need to set the gears back up, if you changed the r&p you need to set the pinion depth to ring gear and ring gear engagement to pinion, if you just changed the carrier you need to reshim the carrier as right now it's too close to the pinion. Your best bet as you need special tools and bearing pullers is go to a junkyard and buy a complete diff and put it into your truck, u bolts are cheap and an improperly setup diff will eat itself with in minutes or grenade and setting up gears for the first time will take you hours to do it right.
You're in way over your head. You need to get someone who knows what they're doing to help you. Axle work is very complicated, precise, and intolerant of mistakes, and you are making quite a few of them.
I've been using these instructions as a guideline to get this this thing back together. I also got a Yukon gear master install kit. I have a few torque wrenches and I borrowed a dial indicator from work. As it turns out, the shims were all wrong and I also had the bearing caps installed on the wrong sides. I have the shims sorted out and I have the backlash set to .010. I am having some problems decoding the paint on the gears. If there are any gurus who can decode the marks for me, that would be amazing.
Looking at where you are now, I would say you need to make a pinion depth adjustment. The paint marks on the drive side ( convex side) are out toward the toe of the teeth. That tells me you need to take some shim out of the pinion. I wouldn't go much more than .002" or .003". It takes very little adjustment to make a difference. Your backlash will increase as you move the pinion away from the centerline of the ring gear; so you will need to make adjustments there as well. The most desirable pattern, you will have an equal sweep on the drive and coast side of the tooth. When you achieve the proper backlash, there should be a thin stripe of paint at the peak and valley of the tooth also. Setting up a gearset is kind of a trial and error situation. I have built more axles than I care to remember. I've had some that only take one or two adjustments, and bam they fall right in perfect. I've had others that fought me tooth and nail, put it together and take it apart a dozen or more times. It takes patience and knowledge to get it done right. You are running a used ring and pinion, it's possible it may sing a little bit. I've had it go both ways, it's a crap shoot. Hope this helps, good luck.
Dober83 go over to classic trucks 48 56 and post your picture. A while back they were talking about this same thing and have a pic of what the pattern should look like. Good Luck.
Dober83 go over to classic trucks 48 56 and post your picture. A while back they were talking about this same thing and have a pic of what the pattern should look like. Good Luck.
04-13-2015, 07:45 PM
