Toyota 8" IFS, 53mm BRNG-RD121- ARB Front Differential Question?

[MeBe4running]

I was wondering if anyone could explain why I might be experiencing this thump since the install of my front ARB air locker differential.

It doesn't happen all the time and when it does its typically at a stand still like, at a traffic light. I will be stationary at the light lets say for a minute. Within 45 seconds of that minute I will sometimes experience this thump. To describe how the thump feels imagine rolling in Neutral (N) at a speed less than < 3mph and then placing it into drive (D). You get this slight jerk from going into gear. Thats what I feel though whilst in drive and my foot on the brake.

I haven't experienced this ONCE prior to the install of the front differentials. This may be a normal thing however trucks that I have driven in the past with air locking differentials never seemed to have this issue? Anyone like to collaborate and explain maybe why? Thank you in advance!

I read a few posts like: http://www.toyota-4runner.org/5th-gen-t4rs/101540-transmission-tranfer-case-issues-2010-sr5.html

and saw 1engineer's post:

I have, on occasion, had a muffled "clunk" when transitioning from the brake to accelerator pedal, usually at a stoplight. It does not happen all the time just on occasion. I am thinking it is the brake release because of where the sound is coming from and I am not worried at all. Just my opinion

 

[phillyd2]

May be wrong but I don't think it would have anything to do with the front lockers - which when not engaged is just a diff. And you would know if it was engaged / locked.

 

[1engineer]

May be wrong but I don't think it would have anything to do with the front lockers - which when not engaged is just a diff. And you would know if it was engaged / locked.

I would tend to agree. I havehad a few vehicles in the past with front air lockers and do not recall anything that would give you that thump. Could be the driveshaft issue and just coincidence.

 

[MeBe4running]

I would tend to agree. I havehad a few vehicles in the past with front air lockers and do not recall anything that would give you that thump. Could be the driveshaft issue and just coincidence.

Me to, I just find it weird that it would happen right after the install. I will see how it pans out and keep this thread posted. Thanks for your response

 

[MeBe4running]

May be wrong but I don't think it would have anything to do with the front lockers - which when not engaged is just a diff. And you would know if it was engaged / locked.

Totally agree and thats why I'm curious as its the FIRST time its ever happened and it happened straight after the install of the front diff. Though like 1engineer said it could be a pure coincidence. :spider:

 

[phillyd2]

Assuming that you did not install yourself it may be worth to have the install shop take a look at all. If you take it to a Toy Dealer can you guess what they will blame it on? :boink:

 

[Narkhelek]

Maybe it's related to the thump drive shaft issues other people have been experiencing such as in this thread http://www.toyota-4runner.org/5th-gen-t4rs/114053-toyota-issues-fix-axle-wrap-driveshaft-clunky-thumpy.html.

Might be worth greasing your drive shaft to see if it has any effect.

 

[Okki]

Do you only have the issue at idle? what if you're coasting under no power? do you have the same clunk at 45 seconds in?

The delay is what has me puzzled. Its almost if the shaft remains rotation and then stops (like stop-start technology). The change in rotational force causing the "clunk".

Okki

 

[MeBe4running]

Do you only have the issue at idle? what if you're coasting under no power? do you have the same clunk at 45 seconds in?

The delay is what has me puzzled. Its almost if the shaft remains rotation and then stops (like stop-start technology). The change in rotational force causing the "clunk".

Okki

Do you only have the issue at idle?

That I have noticed, yes.

what if you're coasting under no power?

Yes, I still get the clunk then as well.

(like stop-start technology).

You mean Toyota might have sneaked in some prototype hybrid system in my 4runner without my knowledge, those sneaky slim balls :lol:

But seriously your correct, I might play with it in 4hi etc... and see if that changes anything. It is as if it stops, find its place and continues, its certainly disturbing enough for me to be concerned.

 

[Okki]

That I have noticed, yes.

Yes, I still get the clunk then as well.

You mean Toyota might have sneaked in some prototype hybrid system in my 4runner without my knowledge, those sneaky slim balls :lol:

But seriously your correct, I might play with it in 4hi etc... and see if that changes anything. It is as if it stops, find its place and continues, its certainly disturbing enough for me to be concerned.

uhmm... if you have it while coasting then you're having it with drive shaft rotation, so much for the idea that it might be our of balance/badly reinstalled.

I'm curious about other thoughts because I'm out of them

Okki

 

[harper7]

I'm not having any noise with my RD121 front locker but then again I'm full time so my front diff is always under power.

Who did your install and were they experienced? Try it locked in 4x4 with and without the front locker and see if you still get it.
The front 8" clamshell(diff) in our 5ths is the same one used on the majority of Toyota trucks like all Taco's ,4Runners, FJ's and Prados since 2003.That being said they are tried and true and so are the ARB RD121 lockers so nothing new there.

The rear 8.2" 12 bolt diff however is a complete new design as of 2010 so people may have problems building them up. When I drained my rear diff fluid for the 3rd member swap my gear oil was still almost clear at 41k miles so it was wearing perfect with a perfect pattern on the teeth.

 

[MeBe4running]

I'm not having any noise with my RD121 front locker but then again I'm full time so my front diff is always under power.

Who did your install and were they experienced? Try it locked in 4x4 with and without the front locker and see if you still get it.
The front 8" clamshell(diff) in our 5ths is the same one used on the majority of Toyota trucks like all Taco's ,4Runners, FJ's and Prados since 2003.That being said they are tried and true and so are the ARB RD121 lockers so nothing new there.

The rear 8.2" 12 bolt diff however is a complete new design as of 2010 so people may have problems building them up. When I drained my rear diff fluid for the 3rd member swap my gear oil was still almost clear at 41k miles so it was wearing perfect with a perfect pattern on the teeth.

It was Safari LTD, in Grand Junction. I'm personally not going back for other reasons as well. I will try it locked and let you know, that was next on my "to do list".

I heard that they had to change a few things in the RD121 especially for the 5th Gen 4runner? I also heard the biggest damage done whilst installing these differentials is the "O" rings which are in the seal housing. Typically if there not lubricated enough or oscillating when "pushed" onto the cylinder cap, damage can be caused almost instantaneously. You would know more though, is that true?

I have actually yet to test the front diff, though the tech did and he said it was working great. With the diff open (like factory) when not engaged it shouldn't have any reason to cause this thump. I find it to hard to believe that is was a pure coincidence that the thump started after the install, I think I need to take it for a second opinion for the work done. What are your thoughts? Thanks Harper7!

 

[harper7]

I heard that they had to change a few things in the RD121 especially for the 5th Gen 4runner? I also heard the biggest damage done whilst installing these differentials is the "O" rings which are in the seal housing. Typically if there not lubricated enough or oscillating when "pushed" onto the cylinder cap, damage can be caused almost instantaneously. You would know more though, is that true?

Nothing changed at all in the RD121. As I mentioned before ,it's the EXACT same 8" clamshell(front diff) as the last 10+ years. About as good as you can get for a IFS and relatively bullet proof and problem free!Millions of happy customers worldwide as I was just reading Hilux's have them too and they are everywhere on the planet. My front diff was a swap and built up with the RD121 and 4:56'S gears by Chase at ECGS . No telling what my new one came out of but it wasn't a 5th Gen as he said mine was the first they did one for and that ARB themselves told him the front diffs and lockers were the exact same.

The main problem I've read is how people put on the o-ring and that it will leak gear oil back up the air lines and out the solenoid. But that won't give the noise you described of course.

That's why ARB added this to the instructions.
A twisting motion (i.e., a slight rotation while pressing the seal housing on) will allow the O-rings to engage gently and prevent them from twisting. Twisted O-rings will result in pre-mature O-ring wear and oil contamination in the air system due to the helical shape formed by the O-ring mould line
Here's the install pdf of the rd121........http://store.arbusa.com/Assets/PDF/RD121_i.pdf

 

[MeBe4running]

Nothing changed at all in the RD121. As I mentioned before ,it's the EXACT same 8" clamshell(front diff) as the last 10+ years. About as good as you can get for a IFS and relatively bullet proof and problem free!Millions of happy customers worldwide as I was just reading Hilux's have them too and they are everywhere on the planet. My front diff was a swap and built up with the RD121 and 4:56'S gears by Chase at ECGS . No telling what my new one came out of but it wasn't a 5th Gen as he said mine was the first they did one for and that ARB themselves told him the front diffs and lockers were the exact same.

The main problem I've read is how people put on the o-ring and that it will leak gear oil back up the air lines and out the solenoid. But that won't give the noise you described of course.

That's why ARB added this to the instructions.
A twisting motion (i.e., a slight rotation while pressing the seal housing on) will allow the O-rings to engage gently and prevent them from twisting. Twisted O-rings will result in pre-mature O-ring wear and oil contamination in the air system due to the helical shape formed by the O-ring mould line
Here's the install pdf of the rd121........http://store.arbusa.com/Assets/PDF/RD121_i.pdf

Thanks Harper7, this is exactly the reason I will not be going back to Safari LTD. Its all very well to tell a customer something you know what your talking about but when I hear " they have changed the design, so the install will take a little longer" blah blah I don't know what I'm talking about, blah blah etc... I will go boll*cks to that, harper7 told me..... :thanks:

I tried 4hi and same problem. I also got to an even pitch (slight uphill) at a traffic light and took my foot off the brake. I waited and sure enough it jerked just the slightest bit forward. This happened in both 2wd/4wd. I know its a runner, but thats just not right.

I will swing it by the stealer to see what they have to say. Thanks again for your input Harper7, it is as always greatly appreciated!