Diff pro needed: Ford 8.8 carrier too tight with new locker?

TimboSlice

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So I decided to jump into the differential in my 8.8 swap from explorer with disc. I had a setup in there with the stock carrier i was not fond of. It was installed by a pro and with my new ox locker going in I knew I had to take some backlash measurements and such that ive never done before. All went well until I went to put new carrier back in. I used the cast shims that were in the axle and made sure they went to the proper side (only 2 shims in carrier, none inside carrier bearings.) The carrier is the same dimensions as the factory carrier I removed. It seems like it is very tight going in as I did get it started with the cast shims from ford and race together. Shims were exactly the same and labeled to proper side. I found myself hitting it in with a plastic deadblow. I kept measuring each side with every hit so i would be installing this even. Some of these were not love taps, I wasn't really smashing on it either. I had to struggle and wiggle the old carrier out by prying and turning. I understand there needs to be preload on these bearings so it needs to be snug. My gut just said it was to snug as i was hitting it in. I got it about 3/4 the way in and stopped. I wanted to get some advice and opinions before proceeding. Nothing is binding as far as the ring and pinion, but its not all the way in either. All bearings were replaced less than a year on the pinion, so pinion removal was not needed. Are these just a huge bear to get in? Im scared its not going to come out! haha. This is something i have not done before but feel capable of doing the work and checking backlash after the bearing caps are on. Thanks
 
Yes they can require some very solid blows with a mallet to get seated fully back into place.

But seldom is a new carrier's width exactly the same as the original carrier's width. Measuring their widths with a tape measure, for example, is not going to do it.
 
Yes they can require some very solid blows with a mallet to get seated fully back into place.

But seldom is a new carrier's width exactly the same as the original carrier's width. Measuring their widths with a tape measure, for example, is not going to do it.

Thanks Jerry, your input will give me the confidence I need to drive it in there the rest of the way. The pitch from OX was that the carriers are the same size but i totally understand what your saying, as they had me measure and compare certain dimensions. I never thought I was damaging anything while I was installing, just afraid of destroying or damaging something while trying to get it out if adjustments were needed. The races were somewhat angled going in at first, is this normal? Just dont want to leave a detail out before I button this up. Thanks for your input.
 
Your intuition is good, It is pretty standard to have to tap them in. That is your preload. That is why some people use a case spreader instead. I, like you, pound mine in with a plastic mallet.

But @Jerry Bransford is right on the money, no two carriers are the same even if they are stock. They are just not precision cut. While it can be close enough to use the same bearings, it is usually not. So make sure you check the backlash when you get it in there. Thousandths of an inch can throw off your backlash.

A good rule of thumb is tapping the carrier in, and being able to pry it back out fairly easily with a big screwdriver, or small prybar. You shouldn't have to lean on it or wonder if you can get it back out. You basically don't want to be able to push it in without tapping, and you don't want it to fall out.

From the sounds of it, it sounds like you might be a little too tight, so like I said if you do get it in there without breaking anything, make sure you recheck your backlash.
 
Your intuition is good, It is pretty standard to have to tap them in. That is your preload. That is why some people use a case spreader instead. I, like you, pound mine in with a plastic mallet.

But @Jerry Bransford is right on the money, no two carriers are the same even if they are stock. They are just not precision cut. While it can be close enough to use the same bearings, it is usually not. So make sure you check the backlash when you get it in there. Thousandths of an inch can throw off your backlash.

A good rule of thumb is tapping the carrier in, and being able to pry it back out fairly easily with a big screwdriver, or small prybar. You shouldn't have to lean on it or wonder if you can get it back out. You basically don't want to be able to push it in without tapping, and you don't want it to fall out.

From the sounds of it, it sounds like you might be a little too tight, so like I said if you do get it in there without breaking anything, make sure you recheck your backlash.

Ok I would say I was using many solid blows with my plastic dead blow. It could not be pushed in after starting. Its tight, I will say that. Prolly not backing it out with a big screwdriver. There was no tapping it in. Theres not a solid place to hit the carrier on the opposite side of ring gear due to its actuating mechanism. Should I avoid hitting the races with the dead blow? Seemed like it was the only way I can finish getting it in and seated. Also im assuming using the bearing caps to install when its in enough is a bad idea? I assure you none of this is covered in the provided literature.
 
Yeah, I usually set it all together with the caps and spacers lined up then I tap the shim and bearing cap at the same time being careful not to beat on it too hard because the shims are more delicate. You shouldn't have to really beat it in. You should be able to hit it in, but you shouldn't have to really beat on it. It is hard to describe because if you are not going in straight, it will sometimes get wedged.

Do you have different shims you can try? This is really one of the toughest, and time consuming parts of building a diff. Sometimes it takes a few times to get it right.

Here is what I do for the most part. I shim it where I get the backlash perfect, but I can push the carrier in where it is snug, without having to tap it. You know where I an put it in with a hammer handle. Then I make sure the backlash is where I want it, then I pull it back out, and replace the shims with new shims that are about 2 thousandths bigger each side respectively then I tap that in with a plastic hammer, and then recheck the backlash. If I have tapped it in, and the backlash is still within specs, I call it good.

Just to reiterate, once you get your backlash set you want to add the same amount to the shim on each side for preload, and always double check the backlash just to make sure nothing changed. (I hope that makes sense.)

Since you are replacing the carrier, you should not only check your backlash you should also check the pattern when you are done, just to make sure your aren't too deep or not deep enough with the pinion. Chances are you are fine, but check the pattern, so you can feel good when you are done. If your pattern is on, and your backlash is on, then you should have little to worry about.
 
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Thanks for the input. I also searched for videos for this rear axle carrier install. Hard to find a video with similar scenario as mine but watching a few it looks like im having a hell of a time compared to what ive seen. Looks like my next step is try and get it out. I really smacked it in compared to how you are explaining it and how ive seen a few installed. Looks like I made more work for myself. Its going to be a pain getting this out im thinking.
 
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Thanks for the input. I also searched for videos for this rear axle carrier install. Hard to find a video with similar scenario as mine but watching a few it looks like im having a hell of a time compared to what ive seen. Looks like my next step is try and get it out. I really smacked it in compared to how you are explaining it and how ive seen a few installed. Looks like I made more work for myself. Its going to be a pain getting this out im thinking.

Yep, then it is too tight!
 
Make sure your case bearings are fully seated.

The case “deck” height should be the same as factory.

You should use factory shim deck height even building a new shim stack.

Are the gears tight while going in or is the case tight right away in the housing?

Don’t hit shims if you can avoid it. Easily break, can hit the raceswith a brass punch to help guide it as well.


Case spreaders also exist and for reason some of the suckers are tight.
 
They are fairly tight but they should not stop when being hit with a dead blow hammer. The cast shims are brittle and will break if hitting them directly. Best to use a shim driver tool which is circular which spreads the impact load to more surface area.

The better option is to place the shims in the housing, slightly tilt both races, start the carrier in place, lightly tap the races flat, then use a dead blow to seat the carrier.

Carriers are not the same width, even from the same manufacturer. If they were, there would be no reason to have different thickness shims. Once you get it all together you need to check backlash. You want .008-.012 on the 8.8.
 
Make sure your case bearings are fully seated.

You should use factory shim deck height even building a new shim stack.

Are the gears tight while going in or is the case tight right away in the housing?

Don’t hit shims if you can avoid it. Easily break, can hit the raceswith a brass punch to help guide it as well.

The gears are not tight when I put it in. The case is tight right away. Again its not fully set. There are 2 cast shims that I am reusing, on for each side. I ordered other shims but I am trying to install using the stock shims. Again I stopped about 3/4 way in due to my gut feeling I should reach out to the forum.

The better option is to place the shims in the housing, slightly tilt both races, start the carrier in place, lightly tap the races flat, then use a dead blow to seat the carrier.

This is what I did, both cast spacers are in before races set in on angle.
 
Yes they can require some very solid blows with a mallet to get seated fully back into place.

But seldom is a new carrier's width exactly the same as the original carrier's width. Measuring their widths with a tape measure, for example, is not going to do it.

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The gears are not tight when I put it in. The case is tight right away. Again its not fully set. There are 2 cast shims that I am reusing, on for each side. I ordered other shims but I am trying to install using the stock shims. Again I stopped about 3/4 way in due to my gut feeling I should reach out to the forum.



This is what I did, both cast spacers are in before races set in on angle.

It is really hard to say for certain if you are having an issue or not over the internet. It is also hard to say whether or not you are hitting them hard enough since "smack it with a hammer" is hard to quantify.

If I had to guess, I would say the shims are probably just a bit too thick for the new carrier.
 
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Little update. So I had some time this evening to head out to the shop with a fresh mind and more knowledge from the help of all of you. It was to tight. I removed the carrier and just kept at it. Its tedious, but at my last attempt for the evening, I am very close. I am at .002 and I know I am going to need .008-.012. I ran out of time for the night and walked away much happier and with alot more knowledge than I started out with. I found that I was hitting this much much harder than what was needed to get to .002 with the gears spinning smooth and bearing caps torqued. All shims are outside the bearing race on the 8.8 rear end. I knew this but wanted to make it clear if anyone does a search in the future. If there are more suggestions, im all ears. Best tool for learning this is patience. I feel most of us can do this task as long as your not a hammer thrower or feel you can scream at things to make them work. Will a shim of .006 on the right get me into spec?
 
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So you have a couple choices really. If your really had to pound it in there you could probably just put a little bit smaller shim on the left side and tap it back in, but if you are happy with the force it took to get it in there then remove .006 from the left and replace .006 to the right. That way it will give you the backlash you need and will pound in the same. Make sense?
 
So you have a couple choices really. If your really had to pound it in there you could probably just put a little bit smaller shim on the left side and tap it back in, but if you are happy with the force it took to get it in there then remove .006 from the left and replace .006 to the right. That way it will give you the backlash you need and will pound in the same. Make sense?

This totally makes sense. Except the shim on the left is the one piece cast shim. I would have to make a new one with multiple shims. I think my last post was misleading. I did not have to beat it in to get my .002 like my very first post showed as my concern. This went in nice.
 
If your backlash is .002, you need to subtract shim from the left and add shim to the right. If you are using the solid cast shims you either need to find others of the correct thickness or use a different style of shim that sandwiches thinner shims between two thicker shims.