14 bolt FF

[aarolar]

So my SF has developed alittle whine when under a load like going up a hill or under accel, coasting it's quiet as a mouse. Now instead of rebuilding my SF I am considering swapping in a FF, if I get a FF from another GMT400 it'll be a simple unbolt and switch right? Also what 3/4 tonn trucks came with a FF instead of a SF?

 

[great white]

So my SF has developed alittle whine when under a load like going up a hill or under accel, coasting it's quiet as a mouse. Now instead of rebuilding my SF I am considering swapping in a FF, if I get a FF from another GMT400 it'll be a simple unbolt and switch right? Also what 3/4 tonn trucks came with a FF instead of a SF?

8600lb GVWR trucks. That's as heavy as 3/4 trucks get, then you're in to 3500's.

I'll leave 'burbs and vans out because things get weird with them....

 

[aarolar]

8600lb GVWR trucks. That's as heavy as 3/4 trucks get, then you're in to 3500's.

I'll leave 'burbs and vans out because things get weird with them....

Well scratch my original question I just went out and poked around under mine and I actually have a FF axle. Now I am stumped as to what direction to head next with the whine, could it possibly be a u-joint going bad, I just felt them while I was under there and they didn't seem bad at all but we all know that's not a good test. Is it possible that a 14bolt FF could be going out with only 183k miles on it? If so how hard is it to rebuild for someone with a machine tool background?

Edit I found this excellent article about setting up gears in a FF and it seems like something I could tackle. I still find it hard to believe that it is shot in this truck but I guess anything is possible.

http://www.pirate4x4.com/tech/billavista/PR-ARB/articles/14b_Gear_Setup/

 

[great white]

pop the fill plug out and make sure you can touch fluid with your pinky just below the hole. Low (or empty) oil will make them howl like a sumanabatch.

If it's low, most likely your hub seals are leaking unless there's something obvious like the front carrier or cover leaking....

 

[aarolar]

Checked it earlier and it is good I can touch it with my pinkie, I bought all the stuff to change the oil untill I found out I had a FF instead of a SF...

 

[aarolar]

Ok so I finally got to remove the diff cover and check things out this afternoon, I am about ready to go on a shooting rampage in orilleys apparently anyone that can breathe and walk is qualified to work in there but besides that.

Few observations,

-Seems like I could see some play in the carrier bearings and pinion bearings that doesn't look good at all but it was minor and hard to tell 100% what I was seeing

-The gears looked excellent almost no noticeable wear at all

-Google research told me that a FF rearend holds 3.7 quarts of oil, I was struggling to get 2.5 quarts in level so I took it outside and parked it on a hill and managed to force about 3.5 quarts in by quickly squeezing the out of the last bottle and then jamming the plug in as fast as possible. Can anyone with a owners manual please verify what it actually holds?

-It seems alittle quieter now after a fluid change but I didn't take it very far down the road so it'll be another day before I know for sure. What I removed from it looked more akin to used up 5w-30 than gear oil.

So now I guess I am going to start gathering up parts to rebuild this beast of a rear end, the article on pirate and having it apart today looking at it makes me feel pretty confident I can handle it myself. I can't understand what in the heck somebody was doing with this truck to be able to wear out a 14 bolt FF in 182k miles gee wiz I thought this thing was "bullet proof".

 

[great white]

Everything wears out if neglected.

Fluid change is one of the important things.

If it flowed like 5w30, it was long past abused.....

 

[19trax95]

It probably says 3.7qts because the hubs get oil too. The way I fill them is drive half the truck on a curb and let it sit for a few minutes. Then do the same b7t the other side. It just lets the oild run down the axle tubes into the hubs.

Sent from my SCH-I605 using Tapatalk 4

 

[aarolar]

Everything wears out if neglected.

Fluid change is one of the important things.

If it flowed like 5w30, it was long past abused.....

True, true...

 

[454ss]

if it has the g80 gov-loc im sure that weak pos is on the way out too. if it does did you add the little bottle of additive for the clutch plates?