Hello all this is my first time here , and I was wondering if anyone could shed some light on my issue . I am a diesel mechanic , and I am having trouble with my rear axel slipping in my lsd. I have changed fluid to royal purple gear oil for lsd rear ends , added the friction modifyer the whole bit . im going to try and swap the oil for the 140w90 synthetic that they reccomend ,as well a the friction modifyer . I guess my main question is , my axel is a dana 60 and it has 4.11 for ring and pinion in it . Its my old service truck , but now since i bought it the box isnt on it anymore and my tools are in my new truck , so i want to put a lower sped axel for better mileage in it , but im wondering what will work . its a 2wd with a 8 foot box . What model year do you reccomend that i put in it to give me good mileage and low rpm in my motor in overdrive ? All i will be hauling is a bale of silage once and a while or my sled . Thanks in advance , im stuck lol
Just need to clarify something.
You have a 2006 F150 with a Dana 60 axle assembly? Shouldn't be the case unless it was replaced sometime later. The stock offering (even on payload package models) is a 9.75" ring gear. The available gearing option should be a 4.10. You can find other stock F150s with a 3.73 or a 3.55.
If you're really having issues with the limited slip, the you could replace the entire assembly to something like the TrueTrac from Detroit/Eaton.
If you have a Dana 60 on a 2wd F150 I would be extremely surprised. Even if it is a work truck that is a large axle for these trucks and overkill in most cases. But if you were having issues with limited slip and didn't add the friction modifier then the problem would continue. Changing the gear oil to Royal Purple is fine but it should of been the 75w140 even if you changed to a different brand. So if you used something else then you may have an issue with that too which means a fair amount of money just got wasted unfortunately.
I would check your axle again and get the correct fluid and modifier in there to fix the issue. I believe there is a TSB to for a limited slip issue that you may want to check out.
i checked the stamps on the axle and they are 10.25 , the ford dealership told me its a dana 60 .. .. I have put the modifyer in right from the start , it went away , but now its coming back when going up hills . It will slip a couple times modestly then i let off her and then back on her and she stops .. it was royal purple 75w90. and the ford friction modifyer .. my shop had the clutches shimed a while before i bought it .. has anyone heard of any transmition issues with this model year ? does this site post tsb ? you mean service bulliten right >? THanks for the help all ..
Yeah run a search on here for TSB's for rear axles on the model year and I am sure something will pop up. A few guys around here have a link in their sig straight to them but I am not sure where they are.
Where did you get the 75w90 as the fluid for your axle? It may be that was not what was needed but I am not sure as you have a different axle from most. I know for my rear axle (which is different from yours) it requires 75w140 and the 75w90 is for the front axle. Anyway I would search for the axle tsb and also double check the fluid you should use.
i checked the stamps on the axle and they are 10.25 , the ford dealership told me its a dana 60 .
If you have a 10.25 then you should have a Heavy Half. One way to confirm is if you have 7 bolt wheels on it.
I've had a Dana 60 in a previous truck and a 10.25 in one of my current trucks. AFAIK, the 10.25 does not look like nor is a Dana, it's pure Ford. 4.10 may have been the only gear ratio available in this rearend so OEM options may not be available. I have not done much research yet on the subject (due to vehicle warranty) but I suspect to get anything better for highway mileage that you're going to have to go aftermarket to find a carrier and ring & pinion for it, if such an item exists. Probably the most reasonable option would be to replace the whole rearend and the front hubs to switch to both to 6 bolt wheels and change the gear ratio at the same time.
Here's what a pair of 2wd Scabs look like - a 07 Heavy Half Long Box vs a 97 regular Half Short Box.
3 Service refill capacity is determined by filling the axle to 1/4-9/16 inch (6-14 mm) below the bottom of the filler hole with the vehicle on a level surface.
Add 4 oz. (118 ml) of Additive Friction Modifier XL-3 or equivalent meeting Ford specification EST-M2C118-A, for complete fill of 8.8 inch and 9.75 inch Traction-Lok axles.
4 Service refill capacity is determined by filling the axle to the bottom of the filler hole with the vehicle on a level surface.
For 10.25 inch Traction-Lok axles, use 6.5 pints (3.1L) of Motorcraft SAE 75W-140 Synthetic Rear Axle Lubricant and 8 oz. (236 ml) of Additive Friction Modifier XL–3 or equivalent meeting Ford Specification EST-M2C118-A.
5 Your vehicle’s rear axle is filled with a synthetic rear axle lubricant and is considered lubricated for life. These lubricants do not need to be checked or changed unless a leak is suspected, service is required or the axle assembly has been submerged in water. The axle lubricant should be changed any time the rear axle has been submerged in water.
__________________ There's 2007 and there's 1977...
... two good years for trucks ...
Thanks for the info , im going to search for tsb right now !!! .. Thanks for helping me find out what i have for a truck . I figured out it was just a reg truck with a bigger rear axel . The fellow at ford told me it was a dana 60 , I know nothing about what brands are suppose to be in fords lol , I owned a 3/4 ton chevy untill recently when some chick wrote it off .. My rims are 7 bolt , i forgot to mention this as well , they told me reg gear oil would be ok at the dealership , but i read online that they too the 75w140 sysn . I was thinking it was my tranny , but that axel has done some slipping untill the fluid change , and it does it around turns once and a while thats what made me think it was the rear end . Anyone know what models i can get a tranny out of ? i have a 5.4 l in it .. thanks for all the help I will keep up posted and upload a couple pics
... etc .... they told me reg gear oil would be ok at the dealership , but i read online that they too the 75w140 sysn . I was thinking it was my tranny , but that axel has done some slipping untill the fluid change , and it does it around turns once and a while thats what made me think it was the rear end . Anyone know what models i can get a tranny out of ? i have a 5.4 l in it .. thanks for all the help I will keep up posted and upload a couple pics
What I posted was straight out of the Owners manual as to lube and friction additive. Take note of the bold numbers in "dark red" that link to notes.
You do have the 10.25 with those 7 lugs.
In your first post, I thought you said slipping was felt going up hills.
If you feel something goind around turns, it's likely "chatter" and the right additive may cure it. The clutches need to slip some on light throttle turns to allow the inside tire to go slower as it has a shorter way to go. If they don't slip at all, the rear tires are forced to revolve at the same speed and the inside spins or the outside drags but both transmit power. That's what the friction additive allows, the smooth slipping of clutches.
Imagine raking finger nails on a dry chalk board, that's chatter.
Dampen the board slightly, the finger nails slide smoothly yet still about same resistance, that's what you want, no chatter.
Wore out clutches just make it easier to spin the inside rear wheel on a turn while transmitting little power to the outside. Most people never know when they wear out if they wear out.
4 Service refill capacity is determined by filling the axle to the bottom of the filler hole with the vehicle on a level surface. For 10.25 inch Traction-Lok axles, use 6.5 pints (3.1L) of Motorcraft SAE 75W-140 Synthetic Rear Axle Lubricant and 8 oz. (236 ml) of Additive Friction Modifier XL–3 or equivalent meeting Ford Specification EST-M2C118-A.
That's not to say you don't also have a transmission issue.
__________________ There's 2007 and there's 1977...
... two good years for trucks ...
I fill some slipping in rear end going up hill sometimes and I know it is not the transmission as it is coming from further back. and doesn't have the same feel that a tranny slip does. It is more like the limited slip tried to engage on a surface it didn't need too or a time it didn't need to. Usually with following the TSB available for it and changing out fluids with correct fluid and modifier and the issue is fixed.
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