Front Differential Cyclical Groaning/Grinding Noise

I've done some research and according to the first TSB, TSB 0026-15 they deemed the needle bearing at fault, which is understandable as the bushing upgrade is available as an aftermarket fix. They later introduced TSB 0011-18 which basically says to replace the front pumpkin all together. Does anyone know what gives? Obviously this is a much more expensive repair if it's just the needle bearing, so I'm wondering if theres more to this than we might think.

The reason I'm asking is because I have this issue, and it's been getting louder and worst. Initially I thought it was just me, and that I was going crazy, now my passengers ask me about what "that noise" is. I'm regeared to 4.88 on the factory components, minus fresh bearings, and I did the bushing upgrade at the time. I'm not finding any extra metal or anything unusual in the front diff gear oil so I have no reason to believe something is wearing out persay, but this noise is getting worst. I can actually feel it in the gas pedal and in my seat. The gearing and bushing were done 50k miles ago so I dont think it's related to the gearing. I'm wondering if this is related to the design of the pumpkin or maybe the machining or something like that. Anyways if anyone has any insight I'd appreciate it.

Edit: I forgot to mention, according to the new TSB the new front pumpkin they are replacing the old with has a different part number, hence I'm assuming some sort of change was made.

 

What oil are you using and did you do the proper break-in period?

 

I did do a proper break in. As far as oil is concerned, I cant remember precisely, but it's 75w90 weight of sorts.

 

Try 85W-140 (get synthetic). The oil will be a little more expensive, but manufacturers of aftermarket gears recommend thicker gear oil. Also, it's about that time to replace it anyway.

 

I personally had issues with 140 weight gear oil not breaking in my rear end properly. After 500 miles I still had machining marks on the gears. It wasnt until I switched to 75w90 that they actually broke in. Anyways, I'll try it. 2 bottles of gear oil is no where as bad as buying the new part number pumpkin that replaces the old part number according to the TSB.

 

Well, the reason why you still had machining marks is cause it's doing its job. 85W-140 protects the gears better and provides a "cushion" compared to the thinner gear. The reason why gear manufacturers recommend it since you are playing with non-OEM parts. Your machining marks doesn't have go away completely in 500 miles. You are just looking at the mark to see if it is even. Similar to the chalk test on tire. The chalk doesn't completely go away, you are just using it as a reference to see if the wear is even.

 

Good point. I didnt think about that. I made the assumption that after 500miles or so they should be mirror finish and fully broken in more or less.

 

I use Royal Purple 85w-140 on my gears. A couple of people in this forum said that ECGS told them to use Lucas 85W-140 since that's what they put in when they regear. Just make sure it's synthetic.

I would also do a quick check of the gears. If it's grinding and it didn't do that before, it might be because the oil is not doing its job anymore. At least that is what I would assume.
Post back on here if that fixes it or not so people can refer to it.

 

Does it stop in 4wd? At all speeds? Brakes look good? Constant like a bearing or more clicking/pulsing? Toss a GoPro under where you think the noise is coming from then switch sides. Also try it by the wheel bearings. Wheel bearings, front propeller shaft U-joint, pinion bearing, CVs, and brakes are all things that come to mind to check on the front past the transfer case. I would think carrier bearings in the diff would be my last thought unless they really messed up the preload or it was low on oil. Hopefully the ring gear and bearing cap bolts were all torqued and thread locked and one isn't backing out, but that would way down my list.

I think the needle bearing was being replaced with another (same) needle bearing previously, so hopefully the new diff has a different bearing type or at least a new manufacturer, but I thought that was the extent of it.

 

I've found that when installing the ECGS bushing in 2 3rd Tacomas, the carrier is loose inside the diff. How I can tell it was loose is when I was done installing the bushing, the driver side carrier bearing shim can move indicating improper carrier bearing preload. This leaves the carrier able move, or simpler term, rattle around. You can pretty much grenade a diff this way. This could be why the TSB had the dealer replacing the entire diff instead of the needle bearing.

 

Damn, that's a big no-no and would ruin carrier bearings then probably gears. he was regeared though, so they should have checked pre-load when the put the carrier back in and adjusted if needed. I wish all diffs used the screw in style tension caps like the Ford 9. It's easy to get lazy with shims and stop adjusting before you are done because you are tired of refitting and call it close enough. But a pro shop should have it right and set up with used bearing tolerances.

 

Yeah, these diffs were factory set. One of em had about 10k miles on the truck. The other may have had 30k miles on it.

 

That's pretty bad. Sounds like they either worked with the used bearing values and they loosened as the bearings broke in or, more likely, they just used a standard shim set and didn't check each one. I didn't feel anything loose, but honestly I didn't intentionally check mine as I didn't expect any issues from the factory.

 

It's a standard shim set. Of all the regears I've done, I haven't seen many variations on shim size.

 

That's crazy. That works for set up speed but not great for longevity. Need those thread in type adjusters. No case spreader or set up bearings needed, no shims to adjust, just quicker and easier.

 

I thought about that, but he regeared and did the bushing at the same time. I would expect the shop that did it to find that discrepancy as it's obvious that something isn't right. He also said that it just recently started and he has been driving 50k+ miles without issue after install.
I figured if it was a loose bushing, he would have had the problem much earlier wouldn't he? Or does it get loose overtime?

 

Theyll get looser over time. Then eventually total failure.

 

Is it only certain years?
Had ECGS bushing on for 35k miles now and had it regeared recently. I had the shop look at everything and told them about the bushing, and they said everything was fine. They removed everything even CV axles and inspected the whole front end when they took the reverse clamshell out. Literally been in the shop for about 3 weeks now since I had them essentially tear the truck apart lol. What do you think the reason it gets loose?

 

So far only been on 3rd gen. One was a 2017 and the other a 19. Its loose because when they are built, they aren't putting enough carrier pre load.

 

Agreed, but the shop should have adjusted the shims for correct preload on used bearings at the time of regear. Once the new bearings set, they shouldn't have much more wear in. Hopefully the shop didn't just pop the original shims back in and call it a day especially if the factory isn't doing it right. I personally haven't ever done a diff replacement or regear and not replaced all bearings and set it back up as new. I always figure that I'm in there and it's worth another $100 for a master kit. You already need a pinion bearing and seal unless you are comfortable pressing them off and reusing, and a new crush sleeve or eliminator. May as well replace the rest of them. I've reused outside axle bearings unless the diff uses C clips as I can always pull retainer plates and change those out pretty easily, but internal stuff is just easier to do while it is on the bench the first time and you can use the old bearings as set up bearings if needed. Curious to see what he finds.