Rear diff leaking fluid w/ stuck fill plug

[XLT]

My rear diff has been leaking fluid for about the past year now and still hasnt run dry. I was going to change the fluid and seal it all back up nice but i ran into a problem. I can't not budge that fill plug on housing. Since i need to fill i read that i could use a bag with fluid in and stick it on in the housing and seal it up as a last resort. I wanted to know if i could fill through hole where the speed censor is located. I realize i would have to measure out the 2.6 quarts instead of filling to the top of the fill plug. Will this work or are there problems with this method?? My dad and i tried with the truck on ramps using a 24" breaker bar and 3" extensition trying to get that fill plug out but the edges are starting to round. If i could put it through that speed sensor hole it would make things easier but i wanted to check before actually attempting this and finding out the hard way that it wouldn't work. Thanks for help in advance

 

[Darrman]

Where is it leaking from, pinion seal, axle seal, dif cover? You could and should try to fix the problem, you lock the axle up at high speed and it aint going to be pretty. As for the drain/fill plug, have you tried waiting till the axle is hot from use to pull the plug? or you could use a butane torch to heat up the area aroung the plug, be careful tho. If you do get it out and dont fix the leak, be sure to hit the threads with some anti-sieze.

 

[XLT]

It is leaking from the bottom of the cover. I forgot all about the butane torch trick. I think i will try that tomarrow. Thanks

 

[IZwack]

yeah try the torch idea.. heat it and put an ice cube up to the fill plug for a few seconds (about 5 seconds.. too cool it down ASAP), then as fast as you cant, try unscrewing the plug out.

when heating, be careful of the speed sensor. i'm not sure if the 1st generation's rear axle is different from the 2nd generation's rear axle, but on the 2nd generation's axle - the speed sensor at the rear differential is only a few inches above the fill plug. therefore, you could melt this plastic sensor. so perhaps you could remove the sensor before you start torching.

as an alternative, if that plug is stuck, you could always just completely forget about the stock plug and get a differential cover that has a fill plug on it (or you can modify your stock cover and put a "drain" plug on it except use it to "fill" the differential). there are a few companies out there that make covers for the 8.8-inch rear axle with plugs on em.. trickflow and summitRacing are two examples :

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IMHO these covers are kind of expensive tho so unless u have $140.00 to spend, i'd personally go with just putting your own plug on the differential cover. just make sure the fill hole is at about the same level as the old fill hole. you can also look at the pictures above to get an idea as to how far up you should drill.
all you really need to do to put one on is to drill a hole and screw the plug in - no welding required. oh and try to drill the hole on a relatively flat area of the differential cover so that the "drain" plug's nuts sits flat against the cover's surface.

heres what a "drain" plug looks like.. i dunno what the inside diamter of that thing is but its probably smaller than the fill plug on ur differential housing.. so, if you put one of these on ur stock differential cover, you'll probably have to use a clear plastic hose to fill your differential... this shouldnt be a pain tho cauz most ppl only change the differentail fluid maybe once a year.

summitRacing has the above "drain" plug kit for about 7 dollars... but you'll have to tack on shipping fees so try looking at your local shops first if you decide to go this route.

 

[Creager]

Do not do the bag idea, unless you doing it to drive your truck to a shop to get it looked at.

You should be able to fill from the speed sensor hole, Fill with 2.5 quarts of gear oil. It might be kinda tight though; gear oil might spill everywhere haha.

 

[XLT]

Thanks alot for all the ideas. I am going to try the torch thing yet but i think i will end up putting a drain plug in the diff cover. The bag idea was a last resort but i see i have plenty of options yet. I figured i could go through the sensor hole but your right it will get messy. I think i will also look around town for a drain plug for the diff cover since i like that idea. Thanks