front axel crack

I have a 2013 taco Sr5 V6 4.0. Owned it since day 1, and has been the best vehicle I have ever owned. I use the truck everyday as a work vehicle it hauls heavy loads and trailers constantly. everything underneath has been upgraded to old man emu and rough country components.
Recently i did a full front end rebuild including
both new C.V. axels pass and drivers side oem replacements
inner and outer tie rods MOOG
all new ball joints Oem lower and rough country upper
upper and lower control arms
camber adjusters Moog greaseable
coilovers and shocks rough country
brake calipers routers and pads Oem and EBC
diff drop kit after market alum pucks
steering rack was perfect so its is stock

Now hear is the problem I was chasing what I though was a bad C.V axel. but after replacing all these parts it didn't solve the problem. I have replaced the C.V 2 times so I don't think I just had a defective axel

when the truck is moving forward everything is fine when the truck moves in reverse usually everything is fine if your moving strait backward. but when you reverse and turn the wheels you will hear 1 loud crack noise come from the front diff and it is always the driver's side axel. if you continue to back up it will only crack once not any more if you drive forward everything is ok never a crack sound.
it will only ever crack 1 time its quite loud and you can feel the resonance threw the entire truck.

I don't think its the gears reason why 2 and 4wheel drive works fine in both forward and reverse
when it cracks it never is the same distance backwards one day might be within the first 10 feet the next day it is 100+ feet before it cracks its totally random usually happens faster the more aggressively the wheels are turned.

Could this problem lie in the neddle bearings or deeper in the carrier possibly a bearing what dose everyone else think this could be.

side note when i replaced the axels 2 weeks ago now the drivers axel was struck in the diff so bad so that to remove it I had to weld on 2 home made threaded rod pushers that pressed up against the housing to evenly put pressure on the axel to remove it. when I got the old one out I didn't see any obvious damage to it I just couldn't pry it out like I have done previously.

any ideas would be greatly appreciated.

 

anyone have any ideas?

 

Stock tire size??

 

no larger summer is 265 75 R 16 and winter is a 265 70 R 17 but i have had these tires on the truck for many many years now and the truck has had a lift kit for a few years now. only recently has this problem arose. I understand the over size problem more stress were and tear ect.. but what is it now that I have to replace is the question.

 

I would sooner think bushings of some sort. LCA, maybe UCA, or maybe even lower shock bushings where it bolts to the LCA

Sounds like a lot of that is new(er)? probably worth double checking

 

U joints?? diff drop might actually be doing more harm than good

 

brainstorming ... wondering if you could get a camera / video down there and have it record to try to isolate this.
- Could the alignment cams be loose and/or mounts be cracked in/around those cams - where reversing shifts the alignment and ... crack? then goes back into place?
- If not the cams, check for cracks around the UCAs / LCAs, shock mounts, tie rods, sway bar -- it's like reverse stresses some area that gives while turned
- When reversing it happens in 2WD right? versus reversing while turning 4wd?
- Is there any chance the sway bar is getting in contact with the shock, tie rod or other components up front? ... something is moving down there ...
- front diff mounts, skids, all other bolts up front torqued / tight?

I was having a strange 'pop' last year that resonated through the truck and I couldn't pinpoint it from the cab. I was able to lay under the truck while my son went forward / back many times to isolate the location. This was joint related. You's is on the front drive side so that doesn't seem likely, but who knows. A camera or something would be great unless you try this but you'd have to get lucky.

 

I don't have a video of it happening but I did do the same thing and have some drive backwards while I am on the ground watching it. To describe it best its like the drivers C.V. gets to a certain point where the stress angle while turning makes it pop in and out and its quite violent on the front end. imagine the c.v being pulled out from the front diff and then popped back in under stress. also it typically happens more when you are backing up turning right.
I don't think the aliment cams are loose I had a professional alignment done and everything goes done the road straight. plus I undercoat the truck 2 times a year with a heavy rubberized undercoating( joys of liveing in northern Ontario in the salt and not wanting a rust bucket of a vehicle) and if the bolts were moving you would see the witness marks in the paint
the problem occurs in both 2 and 4 wheel drive
everything seems tight I don't see any contact of sway bars or anything like that I could be wrong its hard it see with the amount of rubber on everything.

also the other reason why I think its in the front axel today I jacked it up and turned the front wheels. Passenger spun fine no problems what so ever but the drivers side went click click click click as I spun the wheel by hand.
so I put another jack under only the drivers control arm to compress that side more to like ride height and the clicking sound got less.

what inside the front diff grabs onto that c.v axel little locking spring clip. my current theory is that when i back up and turn the wheels this puts a load on the axel to want to come out of the front diff due to lift kit geometry and what not. But what ever that is inside the diff is not properly holding that spring retainer ring on the end of the axel and its popping in and out briefly under high stress low speed conditions. this might also explain why i had such a hard time removing the old C.V axel 2 weeks ago.

 

any other ideas