76 CCDRW...Cummins noises

[76zimmer]

I got my D70 cover blasted last night, and cleaned up today for a quicky paintjob before putting it back on....Have never seen a rear diff cover with a rubber plug in it...how unusual are these?

The Spicer plug:

 

[AJMBLAZER]

Most MOPAR specific rearends have those. The 9.25" and 8.25" are famous for it.

Also famous for them falling out and crap getting in axles with varied results. Seen everything from replacing the cover with an aftermarket one to welding a pipe fitting in and running a pipe bung as a plug.

 

[76zimmer]

haha, I can 't believe its lasted this long. It was in dam tight though,but not enough to keep a drizzle off the cover.

 

[AJMBLAZER]

I think the spicer part is cool.

I wouldn't trust it though. Get a nice high capacity cover or just weld in a normal bung or something.

 

[76zimmer]

I think I'll glue it in, and when I do a traction device install, replace it with a custom DIY4X piece!

 

[AJMBLAZER]

Sounds like a plan. Even just RTVing around it might help,

 

[blazinzuk]

Eric, in your experiences have the truetracs slipped in a towing type environment, or strictly off road type stuff?
I've seen some at the drags (knowingly that they were a TT) and watched launches, and straight and true everytime from what I've seen. No slip, or the car would have launched to the side.

I can't really comment on that Dave. I am sure that in a tow rig with both tires on the ground it will do better than what I am relating. But I am just passing along my observations

Reading those sentiments, I have never "hard-core" wheels my diesels. Been in the mountains lots but not hardcore by anymeans. Eric.I'm curious if those were actual Detroit trutrac? Or something else? Or maybe.they were broken already? I dunno.

So I figured I try my own little experiment on my drive home from the mine. Nothing scientific, but very convincing. Conclusion for me was I am not able to spin 1 tire. I just can't.

Left tire dry pavement flat, right tire 4" wet snow on top of frozen grass on a sideslope. No sign of 1 tire fire. The truck just drives, forward and reverse. And really rooting on it spins the tire on the pavement. No video being alone on a desolate highway.

Luke, yah it was a tru trac I put it in for the guy, 90% of the time it worked awesome, but that 10% of the time he really hated it, we eventually took it out and he sold it. It was only in wheeling situations where one tire was very very light or off the ground, while I doubt Dave will be in that situation with the daully, I just wanted to give a counterpoint to basically give as much information to him as possible.

That is the only one I can confirm for sure was a tru trac, I have been told by other folks they have tru tracs but you never know truly unless you have layed eyes on it yourself.

Given the purpose of the rig the tru trac would be high on my list but if the money was there, the ARB would trump it just because I know the ARB is never going to slip no matter what.

The tru trac will slip and after a bit of reading about it, it seems it is exactly the situations that I describe where it falters ( pretty much like all limited slip diffs). Good weight on both tires and ( in my own experience and Lukes) they seem to work very well, and if Luke can't provide enough torque to the diff to overcome the diff, I think most of us would be good

 

[Deuling]

That spicer plug is pretty cool lookin. Kinda goofy idea but i like goofy

 

[76zimmer]

talking with Kert today about the many variations of D60'70's...differences and similarities in covers and fitment. Kert builds all his covers on a jig, mine fit great, and the 60 has the same bolt pattern as the 70, but the housing is definitely opened up for the 10.5" ring gear to go in there....

Look closely and you can see where the 70 cover resides....the bottom is about 1/2" of coverage with the tin over the housing...the bottom 1/4" of the housing isn't covered, so the 60 cover would be pretty thin for sealing good on the bottom side.



Here is the two covers showing matching bolt pattern...a 85-60, and a 76-70:

Here you can see the 70 cover sticking out a bit more than the 60....it is actually more than you can see, but camera angle takes some away.

The longer bottom end of the 70 cover is obvious here:

The cover installed:

 

[imiceman44]

I know a guy that wheeled with a true trac, and he said sometimes in cases like what you mentionned, he would slightly press on the brakes and it would lock up even with the tire in the air, and once it locked up it was good to go until he let of the gas or got back to good solid ground for both sides.
I have yet to try it myself but seing him drive and never have a problem with it and it being a detroit product I tend to think it will be good.

I can't really comment on that Dave. I am sure that in a tow rig with both tires on the ground it will do better than what I am relating. But I am just passing along my observations



Luke, yah it was a tru trac I put it in for the guy, 90% of the time it worked awesome, but that 10% of the time he really hated it, we eventually took it out and he sold it. It was only in wheeling situations where one tire was very very light or off the ground, while I doubt Dave will be in that situation with the daully, I just wanted to give a counterpoint to basically give as much information to him as possible.

That is the only one I can confirm for sure was a tru trac, I have been told by other folks they have tru tracs but you never know truly unless you have layed eyes on it yourself.

Given the purpose of the rig the tru trac would be high on my list but if the money was there, the ARB would trump it just because I know the ARB is never going to slip no matter what.

The tru trac will slip and after a bit of reading about it, it seems it is exactly the situations that I describe where it falters ( pretty much like all limited slip diffs). Good weight on both tires and ( in my own experience and Lukes) they seem to work very well, and if Luke can't provide enough torque to the diff to overcome the diff, I think most of us would be good

 

[76zimmer]

I had my 99 up in the air yesterday, and noticed the rear G80 locker working as it should? still at 206K on it....one side would spin at a consistent speed, and the other would lock in and catch up, then unlock when it would get up to speed, then do it again and again. My brother had his foot on the brake to begin with and when the pressure was released off the brakes this cycle started.

 

[jltait]

I think overall the G80 in a big axle is a good piece. By big I mean 10.5" or 11.5". I do not have any hardcore wheeling experience with them though. In normal situations they always performed just as or better than expected (I have had 4 of them). I had one in a 9.5" in my '98 Z71 (and yes it had a 9.5" 6 lug 14 bolt due to a heavy chassis package) that would lockup as desired but then would not unlock for a long period of time. It was annoying. Their is a D70 version referred to as a super 70 (IIRC) which GM used in Vans that also used the G80 and "14 Bolt style" spanner nut carrier adjustments. I know that would not work in your D70HD though.

 

[Big Ray]

Hey Dave, this might help clear up some issues about the True Trac...seems it is INFINITELY variable, depending on the traction needed..

 

[folkenheath]

Dave, I think the truetrac is right for you. The street manners will be perfect, and traction will be much better than an open diff, also, no clutches to wear out. Yes, if you get one side in the air, it will just spin one tire, but I don't see you getting the dually in that situation. For sand, mud, snow, ice, etc, it will work great, and still work good on the street. And no actuators and crap to go wrong, I would choose the truetrac over the ARB even if they were the same price for your application.

 

[AJMBLAZER]

Dave, I think the truetrac is right for you. The street manners will be perfect, and traction will be much better than an open diff, also, no clutches to wear out. Yes, if you get one side in the air, it will just spin one tire, but I don't see you getting the dually in that situation. For sand, mud, snow, ice, etc, it will work great, and still work good on the street. And no actuators and crap to go wrong, I would choose the truetrac over the ARB even if they were the same price for your application.

x2.

 

[76zimmer]

I think overall the G80 in a big axle is a good piece. By big I mean 10.5" or 11.5". I do not have any hardcore wheeling experience with them though. In normal situations they always performed just as or better than expected (I have had 4 of them). I had one in a 9.5" in my '98 Z71 (and yes it had a 9.5" 6 lug 14 bolt due to a heavy chassis package) that would lockup as desired but then would not unlock for a long period of time. It was annoying. Their is a D70 version referred to as a super 70 (IIRC) which GM used in Vans that also used the G80 and "14 Bolt style" spanner nut carrier adjustments. I know that would not work in your D70HD though.

Is there something/link/info to explain the differences of the many D70's out there?

Hey Dave, this might help clear up some issues about the True Trac...seems it is INFINITELY variable, depending on the traction needed..

Thanks Ray, I like movies...helps 'splain things to my brain mo better!

Dave, I think the truetrac is right for you. The street manners will be perfect, and traction will be much better than an open diff, also, no clutches to wear out. Yes, if you get one side in the air, it will just spin one tire, but I don't see you getting the dually in that situation. For sand, mud, snow, ice, etc, it will work great, and still work good on the street. And no actuators and crap to go wrong, I would choose the truetrac over the ARB even if they were the same price for your application.

x2.

I'm thinking that will be the way to go too! I put it all back together right now, just don't have the $$$ for a unit right now, but now that I've decided to use the TT, I'll be on the lookout for one for the future rebuild.

 

[Big Ray]

check this vid out...he gets one tire to spin, applies a bit of brake and both wheels start turning again...


truetracs, front and rear...

 

[ashman]

cool vid. I can't see me getting all 4 wheels spinning and then getting out of the truck in my blazer. lol

 

[jltait]

Is there something/link/info to explain the differences of the many D70's out there?

Dave, here is a D70 link to Pirate.

http://www.pirate4x4.com/forum/showthread.php?t=522333

Best information I have found on a D70, There are a lot of variations.

The data presented there indicates the D70HD is a fair bit stronger than the 10.5" 14 bolt. The housing itself is said to be as strong as a D80, but with a somewhat weaker R&P.
JLT

 

[jltait]

I am sure this data is all over, but here is some 14 bolt to D70HD comparison data.
...............................................dana 70hd ---- 14 bolt
steel type:................................nodular iron ---- cast iron
lowest gear ratio:..............................7.17's ---- 5.13's for now
ft lb torque capacity:...8,800ftlb hd /8000 std ---- 6242 ft lb torque
spline count:.................................35 spline ---- 30 spline
preload:............................................shims ---- adjusting collar preload
pinion length:............................longer pinion ---- shorter pinion
pinion support:....................no pinion support ---- pinion support
weight:............................................450lb s ---- 465 lbs
alloys?............................alloy axles available ---- alloy axles available
traction:...........................expensive detriots ---- cheap detriots
thickness:..........................1/2 inch wall tube ----1/2 inch necking down to 1/4-5/16 wall tubes
.................................more ground .clearance ---- less ground clearance

Regards,
JLT