I know that is what the manual says, that's why I called them directly, talked to the engineering dept on the Tru-Trac. The word is emphatically that synthetic is a NO NO with this unit. Something about that the synth. can make the unit noisy during normal operation. Therefore, it's not recommended.

 

I can back this up. When I had my TruTrac installed 2 years ago we just when with the OEM diff oil 75w140 iirc but after driving it for 2 days there was a loud annoying whine. I called Eaton and spoke to a guy named Barney and he asked if I used synth diff oil, I told him I did as the instructions that came with the diff didn't say not too. He said thats the prob with the noise, to use only conventional diff oil with no friction mod at all. So I went back to my mechanic and we swapped out the synth, cleaned it all out of the rear diff, put in conventional diff oil and the whine has never come back. I have nothing but good things to say about my trutrac, very glad I did this mod.

 

Man, that's wierd...doesn't make a lot of sense why synthetic would cause such an issue. Very interesting. Not saying it's not true by any means, but I don't get it.

 

I to am havin the rear end "shimmy" going on with low speed sharp turns. I tryed changing the rear end gear lube. Did not help. The stealership recommend i try doubling up on the friction modifyer. That did not help the issue either infact it gave me a new problem. Terible wine noise now from the rear end all the time! Drives me nutty
Anyways I think I might want to go to the Detroit True Trac.

Can anyone help me out with the part # needed for a 04?

 

Just go to ebay. There are several listers there who sell the unit at attractive prices. They usually ask make, model, and option package then give the model number. Hope this helps.

HYPO

 

2004 with 9.75 axle. Part #913A477
Summit and Jegs both offer the tru trac for $579.

This unit is apealing as it does not have clutches.
Not a bad price at all either. Spoke with local Ford Garage today. They Quoted me $525 min just for clutch pack replacement only. They seem to think the bearing for the pionion will need replaced as well and im looking more towards the $800 range..
I think differently with only 50K miles on the truck.

I also confurmed the gear oil for the tru trac with a Eaton tech today. 80w90 non synthetic.

 

A clutch pack chance and for the most part changing the pinion bearing is a D-I-Y job at home in the garage! Even R & R the pinion bearing would not require checking/adjusting lash and everything. Most detailed thing you'd have to worry about is getting the torque right on the new crush sleve.

IF I were going to go through the trouble of chaning a pinion bearing, you might as well get a good complete install kit and do it all while you're in there. But I'm with you...not thinking you need a pinion bearing at 50K! Sounds suspect...but then again I'd never go to a dealership for rear end work in the first place.

 

I have never done any rear end work.

I was thinking it might be easyer for me to swap out the stock unit with the true trac spool vs. trying to figure out how to replace the clutches myself.
AND then i dont have to worry about the clutches going out again..
Either way im not taking it to the dealer!

Taking into concideration my lack of experiance with rear ends witch route would you sugjuest i take?

thanks in advace for all your input!

 

Find a good shop that either specializes in, or only does rear-end work. That's what I did and I was really satisfied with the outcome. A good source for referrals would be a local hot rod shop. Rodders change gears as often as everybody else changes underwear( more often than some!!!) LOL.

HYPO

 

As a general rule, if you're changing the carrier (the differential) then a complete adjustment is required. Backlash and everything has to be checked and will most likely need adjusting. As mentioned earlier, just changing clutches in the existing carrier would not as you haven't upset anything that alters settings.

Only you know how comfortable/capable you are with tackling a particluar job. So changing the carrier (installing a trutrac) will definitley require a bit of expertise...I'd even take it somewhere for that. But installing clutches I'd jump on myself with no thought. Installing the trutac is probably the 'easier' job, but requries the most 'set up'.


What he said^^^

 

This is all great info. Now im torn between witch way to go..

Cost is certainly an issue. I have not priced the clutches. Anyone know a round about price wise? I can only get them from Ford right?

 

Nope. I know Eaton makes replacement clutches and sure there are many other options. Haven't priced any personally, but can't image they'd me much over $100.

 

Took me a while but i found a parts break down with part #s.
looks like the clutch sets are just over 100$ each.
I think that just made my choice easy.

Assembly looks simple. Once the axles are pulled out it looks like the clutch replacement is a piece of chicken.

thanks again.

If anyone wanted the part# for the clutch set. 9L3W-4947-CA complete kit with shims.

 

glc: Looks like you have the most posts so I amy replying to one with a question. First I am a new member who has just purchased a 2011 Raptor Supercab. I have a 4+ hour drive to get to my ranch where this truck will be driven for work and hunting. This will not be high speed driving, most is more of a crawl because of the terrain with max speed of 30mph. I'm sure I will have enough gears to do that. My problem is mpg as a daily commuter of 20 miles and the 250 miles to get to the ranch. What are my options to change the gear ratio and what would you suggest. Any help by you or others will be appreciated.

 

Yikes. Thats a good question. I have no idea what the raptor has under it for a rear end?
Maybe Galaxy has and opionion?

good luck.