hello, i have a 89 f350 7.3 n/a 5 speed 1 ton, i think that the rear end is a 4.11 and i can not find the fill plug on it. how do i services this think? new to the forum. thanks for the help.

 

See if a 3/8 drive extension will go into a plug on the drivers side front of the diff.

 

that's the thing 87xlt, i can not find a plug, nut, or bolt for the fill or drain on the diff.
this weekend i was doing the normal service on my f350 and bronco, i thought that it might be in the same place as on the bronco, and the 3/8 drive extension works on the rear diff. and the transfer case on my bronco and all so on the transfer case on the f350. right now i'm lost as how to service the rear diff. on my f350. thanks for the help.

 

anyone got some tips on how to pull some routine maintenance on a rear diff. with out a fill or drain plug? the truck is a 89, F350, 7.3 n/a 5sp, 4door, 4x4, 1 ton. thanks for any tips or info. newbe to the diesel.

 

That is a weird one, I would have thought it was on the front of the pumpkin. under the axle. Only other thing I can think of is if you have a sensor in the diff, then measure out the amount of fluid you need into a container.

Take off teh cover, drain the fluid, then put the cover back on. Fill through the sensor hole until you empty your pre measured mix, then replace the sensor.

However I have not had to do this, so I can't see why it would not work in principal. Just make sure there is any way to replace the fluid or you'll be doing a 'junkyard wars' trick...

(saw in an episode where the guy put the measured amount in a zip lock bag, and then welded the diff cover back on - bag inside the diff. When the gears turned, it ripped the zip lock bag releasing the fluid, and therefore working. I do not recommend this however.)

 

i saw the sensor on top of the rear diff. and thought that it was strange that it was the only place that i could use to refill the gear oil. does the sensor just unbolt and slide out? thanks for all the help and info ironpants.

 

I see my post from last night did'nt take.
This might have come from the factory with a fill plug in the diff cover. I wonder if the original owner might have swapped diff covers.

You can probably drain it by removing a lower cover bolt & fill it thru an upper bolt or thru that sensor hole.

What does your Haynes manual say about this?

Interesting way of filling a diff with the baggy, btw.

 

Thats where it is on my sterling 10.25(1992 model)

 

Actually the Zip lock meathod is widely used and I have heard that it is safe. I will use it IF needed out on the trail.

I would go ahead with this bag trick, but its your rear end (get it).

 

looking at my 1980-196 bronco,f100 thru f350 haynes manual it seems to me that the rear diff. on my f350 is a type of dana full-floating axle and it looks like the fill plug is one of the bolts to the cover. new one for me, never had a diff. larger than 8.5 or 9 on the mustangs and broncos that i've owned. to bad that my haynes book does not cover diesel. thanks for the help everyone.

 

The plug for my '94 Dana 60 is in the cover. On the '96 sterling it's on the front drivers side.

I can't imagine why any company would make a replacement cover without the fill hole, unless they had a dipstick.

The ziplock trick is used mainly for trail repairs. You can keep the fluid from getting on the ground, then reuse. Don't know for sure if it hurts any thing if left in for extended periods.

 

In a 350 you should have a Sterling 10.25" rear axle. To drain the fluid you have to remove the cover. The fill plug should be about the same height as the pinion shaft on the front of the differential. The fill plug should be about half way between the pinion and the axle tube on the drivers side of the punkin.

 

After all this time, hope you are still around. You da man. That front driver's side on side of case was hidden under grease. and thanks to you, I found it.
Knowledgte... and experience are wonderful things... few have.