4.11 gears

MUSKYMAN

MUSKYMAN

Well-known member
Apr 19, 2004
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OverBarrington IL
Corey

I agree that the TC's can whine...matt has owned a disco a pretty long time so I figured he knows that sound.

they really do make a racket if the oil is to thin...some jiffy lube type places fill them with auto tranny fluid and that makes them howl!!

the lucas oil stabilizer really shuts the TC's up to a great extent, I run it 50/50 with synthetic gear lube.
 
craig

craig

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Oct 1, 2004
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Edmonds, WA
overlandnavigator.com
MUSKYMAN said:
Now one more thing...the air tube to the air collar should not have to cross over ring gear. the collar on a RD56 is located on the oposite side as the ring gear and the best location for the housing fitting is above the center of the carrier so the tube runs next to and around the carrier no where near the ring gear.
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Thom,

That's true on the RD56s, but the new RD128s run the copper tube over the ring gear. We just set one up in my truck and were a bit surprised by this when we read it in the instructions too.

I've got a picture but it is still on the camera.

Craig
 
MUSKYMAN

MUSKYMAN

Well-known member
Apr 19, 2004
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OverBarrington IL
I just made a call to ARB USA and the reason for them moving the air collar is that the new RD128 is their 2 piece carrier instead of the three piece and this eliminates the need to have a plastic air conduit inside the locker as well as the fact the carrier case itself is stronger.

this is the same design they use on the ford 9" and toyota 8" and they said that the new RD128 is much stronger internally then the RD56's even though they never really had any issues with the RD56's

progress I guess
 
DiscoveryXD

DiscoveryXD

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May 1, 2004
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where i'm at right now, duh...
flyfisher11 said:
I use the same recipe.
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gonna go to the autoparts store and give Lucas a shot. I talked to Bill a bit this morning and we decided that I should play around with the pinion angle some. With this new DC shaft, my pinion angle was probably not steep enough. So I went out and removed the 1/2" spacer I had in place for a 1/4" one on the trailing arms. Took it out for a test drive and that seemed to help. I'm gonna drive it around a bit more, and see if taking the 1/4" spacer out too may help some more. It's obvious this truck isn't going to drive like a stock disco on street tires, but it does feel better than before.

I know there have been some debates on here with Bill, but I can say that he and Shawn have been very helpful with all of this, and hopefully this new diff will work out just fine.
 
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MUSKYMAN

MUSKYMAN

Well-known member
Apr 19, 2004
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OverBarrington IL
DiscoveryXD said:
gonna go to the autoparts store and give Lucas a shot. I talked to Bill a bit this morning and we decided that I should play around with the pinion angle some. With this new DC shaft, my pinion angle was probably not steep enough. So I went out and removed the 1/2" spacer I had in place for a 1/4" one on the trailing arms. Took it out for a test drive and that seemed to help. I'm gonna drive it around a bit more, and see if taking the 1/4" spacer out too may help some more. It's obvious this truck isn't going to drive like a stock disco on street tires, but it does feel better than before.

I know there have been some debates on here with Bill, but I can say that he and Sean have been very helpful with all of this, and hopefully this new diff will work out just fine.
Click to expand...

if the pinion bearing is bad, incorrect pinion alignment will make it much more noticable on and off the throttle.

making the pinion angle correct may make it make less noise but that will not fix the bearing.

if you were running it with a incorrect pinion angle you may have done in the bearing because the vibrations from a incorrect pinion angle will over time destroy the rear u-joint and cause the pinion bearings to fail.

my comments have nothing what so ever to do with Bill or GBR or the original set up, my gut tells me that they did everything correctly when they built the third member. But the fact that now you are saying that you may have been as much as 1/2" spacer off on the rear arm length makes me even more sure the pinion bearings are the issue here. 1/2" spacer makes a huge difference in pinion angle and that I would bet is at the root of the issue here.
 
A

ashtrans

Well-known member
Dec 15, 2006
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Hi no help with the problem in hand but just a comment regarding the late RD56/128 with the 'spring located air collar' and later diffs with the single roll pin in the bearing cap. We have had at least 3 warranty issues due to the installer catching the air line at install and/or the air line catching on the crown wheel teeth, we now route the line down the same side as the crown wheel to avoid this issue.
The second and more common problem was caused by the roll pin. Originally this pin was used to stop the side adjuster nut moving. After the ARB install the pin now goes into the slot in the 'air collar' and there is nothing to stop the adjuster nut moving. As the adjuster nut moves, believe me it does even with loctite applied to the thread, the air collar is forced off center and which causes it to leak air. Drill and tap the bearing cap 8mm, 5/16" approx 12mm 1/2" behind the roll pin hole, before assembly then after completing side load and backlash adjustment screw in a grub screw to lock the side adjuster nut. do not fit the roll pin. PM us if you need a photo of pipe route.
Best of luck with the actual problem in hand.
Ian
 
MUSKYMAN

MUSKYMAN

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Apr 19, 2004
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OverBarrington IL
Dave thats some great tech!

If you could take a couple pics and send them to axel or Ho and I will bet they will put them in the tech section for people to see in the future.

once again great tech and thanks for sharing that!
 
DiscoveryXD

DiscoveryXD

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May 1, 2004
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37
where i'm at right now, duh...
MUSKYMAN said:
if the pinion bearing is bad, incorrect pinion alignment will make it much more noticable on and off the throttle.

making the pinion angle correct may make it make less noise but that will not fix the bearing.

if you were running it with a incorrect pinion angle you may have done in the bearing because the vibrations from a incorrect pinion angle will over time destroy the rear u-joint and cause the pinion bearings to fail.

my comments have nothing what so ever to do with Bill or GBR or the original set up, my gut tells me that they did everything correctly when they built the third member. But the fact that now you are saying that you may have been as much as 1/2" spacer off on the rear arm length makes me even more sure the pinion bearings are the issue here. 1/2" spacer makes a huge difference in pinion angle and that I would bet is at the root of the issue here.
Click to expand...


I see what you're saying Tom. I had the pinion angle set a long time ago with the stock rear shaft in. I just recently replaced the rear shaft with a Tom Woods, and I had this problem before I replaced the shaft. So I know the new shaft didn't cause this because the problem was there with the stock shaft.

I actually have been driving with the old shaft in recently cause I took the new shaft out a day or so after I put the 2nd diff in. So I only drove around with the new shaft on for a little bit this week ( i took it off because of the noise, thinking it was the new TW). Maybe that was enough to damage something? I don't know...

I just put in the Lucas ( sorry Craig! didn't see your post in time) so we'll see what that does.
 
G

GregH

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Apr 24, 2004
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X2

I run two spacers totalling 7/8".

IIRC-years ago JBS told me to start with that amount for my 3" lift and when I checked the pinion angle it was perfect (back to stock).
 
Andrew Homan

Andrew Homan

Well-known member
Jun 7, 2004
3,682
0
Alaska
GregH said:
X2

I run two spacers totalling 7/8".

IIRC-years ago JBS told me to start with that amount for my 3" lift and when I checked the pinion angle it was perfect (back to stock).
Click to expand...

X2 or 3 ;)
 
MUSKYMAN

MUSKYMAN

Well-known member
Apr 19, 2004
8,277
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OverBarrington IL
his bushing is behind his frame ear

running a DC I think it still needs to come UP

go to home depot and get a magnetic angle finder, the flat area on the bottom of the third and the shaft need to be from 0* to 3* apart .

for every degree outside 3* the u-joint loses 10% of it duty life.

I am sure Marc was thinking you were running a single cardan...then it would need to go down.
 
Roverdoc

Roverdoc

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Dec 12, 2004
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California
matt....not sure why you are running a dc on the rear but i believe you and musky are right but this means no spacers and it still wont be "inline" and your tires are going to be closer to the fenders....i would just run the stock driveshaft with spicer ujoints...lengthen if you want but i dont think its necessary with a 3 inch lift....then the pinion should be flat and the two big spacers as mentioned earlier...cheers and good luck. dan
 
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