Changed oil in the rear end, what a diff...!

JCoop · #1 (**permalink**) 04-02-2010, 02:04 PM

I hit 6000 miles last week and I had been hearing some groaning in 5th gear at low speeds in the rear end. Only in 5th. I researched and searched all the forums and the solution suggested in more than a few threads was an oil change to Amsoil Severe Gear 75W90 and a tube of LSD friction modifier.
I did it today, the old fluid was very thick and metallic gray. (wear?) it took 2+ quarts + the friction modifier. Test drive...totally silent in all gears. I'm amazed!
I'm not an Amsoil dealer/distributor/stock owner. In fact, I think I paid too much: $ 15.50/qt.! ...but worth it.

I also decided to change the Tremec's fluid with 3 qts of Pennzoil Synchromesh. I had found out that it's exactly the same as GM Synchromesh, which PZ, as well as Texaco, manufactures for GM under contract. The old oil looked golden new and clean but what the heck. It feels no different, just a bit more "definite", not as slick. Some may describe it as "notchier".

Bob In Ct · #2 (**permalink**) 04-02-2010, 02:55 PM

Ray:
To me it sounds like the transmission fluid made the difference. How would the rear-end know which gear you're in?

Bob

JCoop · #3 (**permalink**) 04-02-2010, 03:18 PM

Come to think of it, Bob, you're right. I guess I should have driven it after one change. Now, I'll never know what it was...

It DID also make but a slightly different grinding/groaning noise in 4th at low speeds, but only towards the end there. Like last week when I drove it like this.
1500 RPM and below. I know, I shouldn't really be lugging this engine but one of the redeeming qualities of the big block was being able to do it: loping around in 4th or 5th. It certainly sounded like it was coming from the back.

Would harmonics have anything to do with it, perhaps? Just that right combination of engine rpm/diff rpm? IOW, running 1500 rpm in 3rd turns the diff a diff amount than 1500 rpm in 5th?

Excaliber · #4 (**permalink**) 04-02-2010, 04:53 PM

Diff turns the same rpm regardless of the trans gear your in, that just changes the rpm of the engine. Mph changes the speed of the rear gear.

JCoop · #5 (**permalink**) 04-02-2010, 08:19 PM

Quote:

Originally Posted by Excaliber

Diff turns the same rpm regardless of the trans gear your in, that just changes the rpm of the engine. Mph changes the speed of the rear gear.

That's what I meant, really. If I'm doing 40 mph turning 1500 rpm in 5th, I'd be turning maybe 2000 RPM doing 40 mph in 4th. So the diff DOES know what gear the tranny is in. So, 1500 rpm in 5th could be a unique event where the diff would groan due to vibration or the way the gears mesh because of that particular combination...

RICK LAKE · #6 (**permalink**) 04-03-2010, 05:01 AM

JCoop Ray was the fluid silver looking from the rearend or trans? Is there a magnetic drain plug on both? If you have a bearing going bad, new fluid will stop the noise for a few miles, maybe 25-50. Then the noise will start to return. I know the 460 makes big low end torque, if you are lugging the motor you will start the drive train to have pulsing that comes from the motor lugging. What is happening is a slapping of the gears back and forward caused by lugging. this pounds the crap out of the bearings.
I don't know how hard you are on the car but if you are running a TKO 500 trans and the motor has a little work done to it, you are over the torque rating on a 500. I would teel you to jack up the car and get a mechanic stefascope and listen for noises in the drive train. If you hear a groining or grinding in the trans or rearend that doesn't sound normal, it is better to repair it now that break down on a trip or have a failure at highway speeds. Silver fluid in either part of the drive train is not good with only 6 k miles on it unless hard driving. There have been alot of problem with bearings coming from over seas that are NOT up to spec and laminate splits in a couple of thousand miles. You can hide the noise for a short time. Rick L.

JCoop · #7 (**permalink**) 04-03-2010, 05:15 AM

I hear ya, Rick. Both don't have magnetic plugs on them, the diff doesn't have a drain at all. I should drill one as shown in SCOF. The old oil in the tranny was clean like new, but the diff oil was muddy and metallic gray in color. I'll drive it today to the Hamptons (about 140 miles RT) and see how it sounds after that.
I also promise never to lug the engine again.

madmaxx · #8 (**permalink**) 04-03-2010, 08:20 AM

what is the lubricant Superformance put in the rear end from factory? How did you select the brand you used.

JCoop · #9 (**permalink**) 04-03-2010, 04:46 PM

I read the Tremec installation guide and they recommend GM Synchromesh only. It's about $15 a qt. at the GM dealers. Then i found out that that oil is manufactured by Pennzoil under contract and the PZ version is branded as Pennzoil Synchromesh @ $7.30/qt. TExaco also makes it for GM and markets it as Texaco T34 or something but I couldn't find it anywhere.

For the rear end, I've looked at various forums, including here, and the resounding recommendation seems to be Amsoil Severe Gear 75W90 and adding the friction modifier. If you google "oil for Ford differential", it kicks up various sites that discuss it. Redline and Royal Purple brands were mentioned also.

It's working great, so far.

madmaxx · #10 (**permalink**) 04-03-2010, 08:28 PM

Thanks,

I have the dana rear end not the ford. I guess i should spring for the new manual, heck on scof they werer talking 75W140 for the rear. I love spf but at time it is challenging on fluid recommendations. then again i should ask them LOL. Problem is if I call spf/ Lance, I'll order a something LoL!!

JCoop · #11 (**permalink**) 04-04-2010, 06:40 AM

Quote:

Originally Posted by madmaxx

Thanks,

I have the dana rear end not the ford. I guess i should spring for the new manual, heck on scof they werer talking 75W140 for the rear. I love spf but at time it is challenging on fluid recommendations. then again i should ask them LOL. Problem is if I call spf/ Lance, I'll order a something LoL!!

MM, I would have gone with the 75W140 too, which, I think I will do after I install a drain plug as recommended at SCOF. The oil that's in there now will be an expensive flush, as I really couldn't suck all the old oil with a hand pump.
But, that would be a midsummer doldrums kind of project...

my427cobra · #12 (**permalink**) 04-04-2010, 08:19 AM

Good morning all: From the last post "I will do after I install a drain plug as recommended at SCOF". What's SCOF ?????

Greg

Got the Bug · #13 (**permalink**) 04-05-2010, 09:27 AM

Quote:

Originally Posted by JCoop

MM, I would have gone with the 75W140 too, which, I think I will do after I install a drain plug as recommended at SCOF. The oil that's in there now will be an expensive flush, as I really couldn't suck all the old oil with a hand pump.
But, that would be a midsummer doldrums kind of project...

Ray,

I took a look at the instructions on SCOF for drilling/tapping the rear end for a drain plug. It looks like a nice upgrade and would make the job a lot easier.

Have you ever run across any info regarding a basic recommendation regarding the miles between rear end fluid changes for a car that is only driven on the street? I'm guessing that it's similar to the maintenance requirements for the trans fluid.

JCoop · #14 (**permalink**) 04-05-2010, 10:04 AM

Quote:

Originally Posted by Got the Bug

Ray,

I took a look at the instructions on SCOF for drilling/tapping the rear end for a drain plug. It looks like a nice upgrade and would make the job a lot easier.

Have you ever run across any info regarding a basic recommendation regarding the miles between rear end fluid changes for a car that is only driven on the street? I'm guessing that it's similar to the maintenance requirements for the trans fluid.

Doug, judging from this experience and what I saw, I'd say a change is called for after the first 500 miles, then another after 5000. $50 is cheap insurance.

I don't know if mine was ever changed after the initial break in as I'm the second owner. I'll put another couple of hundred miles and change it again just so I can see what's happening after this.

Excaliber · #15 (**permalink**) 04-04-2010, 08:30 AM

SCOF is a secret decoder ring available ONLY to SPF owners that allows access to the hidden areas of a secret web site related to all things SPF.

Sssshhhhh, don't tell anybody I told ya...

Now do the Google.

Woodz428 · #16 (**permalink**) 04-04-2010, 09:33 AM

Quote:

Originally Posted by Excaliber

SCOF is a secret decoder ring available ONLY to SPF owners that allows access to the hidden areas of a secret web site related to all things SPF.

Sssshhhhh, don't tell anybody I told ya...

Now do the Google.

Ernie, that used to be true. But they have sold os many cars the cost of the decoder ring has gotten out of hand, what with the constant fluctuation in the $$. It is now a secret handshake, done over a skype link. Because of the break up in the transmission, you often have to do it several times in order to get authentification.

CobraEd · #17 (**permalink**) 04-04-2010, 10:07 AM

So, . . . Have you guys traveled much lately ???

.

kayakjack · #18 (**permalink**) 04-04-2010, 07:38 PM

Ray,

I wonder if the sounds coming when you were in 5th gear could have been due to low fluid level in the transmission? You drained and filled. The old stuff looked fine. You filled with good stuff. I assume there was good stuff in it before. If it was low and is now full, maybe that (low fluid level)would cause the symptom and provide the cure (proper fluid level).

Jack

JCoop · #19 (**permalink**) 04-05-2010, 08:37 AM

Quote:

Originally Posted by kayakjack

Ray,

I wonder if the sounds coming when you were in 5th gear could have been due to low fluid level in the transmission? You drained and filled. The old stuff looked fine. You filled with good stuff. I assume there was good stuff in it before. If it was low and is now full, maybe that (low fluid level)would cause the symptom and provide the cure (proper fluid level).

Jack

Could be, Jack. Unfortunately, the old oil went straight to a drain pan with a lot of other gunk. Couldn't really measure. Old tranny oil looked almost exactly like the new stuff I was putting in (liquid gold).
Not sure if groaning is a known symptom of low tranny fluid in a Tremec. Maybe the tranny gurus can verify?

I was pretty convinced it was the rear end judging from the directional "feel"; especially since I've had the top up until last Friday...

Got the Bug · #20 (**permalink**) 04-04-2010, 05:21 PM

This has been posted before, but I thought I'd go back and refresh my memory about the maintenance recommendations for the TKO trans. JCoop mentioned that the oil in his tranny looked like new after 6,000 miles. Unless you track your car a lot, I'm guessing that you really don't need to worry about changing it for a long time.

"Maintenance
Recommended oil change intervals should be based on specific usage. In most cases a “fill for life” is adequate, while in severe applications such as drag racing, or road racing a more frequent fluid change should be prescribed. Excessive heat will cause most fluids to breakdown and ultimately cause damage to the transmission."

http://www.ttcautomotive.com/English...ps_117_117.pdf