Front Actuator Swapping/Axle refilling

[MIPS]

My front SelectDrive actuator appears to be either stuck or the previous owner has locked it permanently engaged. I have a replacement I want to swap in but doing so requires draining the axle and the filler plug is not easy to reach. Is it safe to refill the axle using the breather hose instead with a measured amount of fluid?

[amcfool1]

hi front actuator is its own system, does not get lube from diff

[djm3452004]

Hi amcfool1 -- I'm glad you pointed that out as I believed the exact same thing as MIPS.  Based on what you're saying, I'm assuming the small threaded pipe plug in the actuator "box" iron casting is the fill/oil level port for the actuator?

And MIPS -- if you don't mind, could you possibly name your source for the front actuator please?  I was hoping to obtain another.

Thank you both!

David

[amcfool1]

hi, its been a while since I did this, but I believe it is. Takes 5 oz  85W-90. btw, new gaskets are still available from Jeep places
good luck, gz

[amcfool1]

as for changing the front diff fluid, I used to have a trans shop do mine. They would take out the fill plug, then suck out old fluid, then refill. Doing it yourself is a real pita . Since then, I have had a custom front diff cover installed, with much more accessible drain and fill plugs. Check out www.yourcovers.com  (PML), in California. P/N 5058. NOTE- this NOT a bolt on, middle front fins have to be machined off for clearance, but it does come with an easily accessible bottom drain. What I did, was ignore the front fill plugs altogether, and drilled/tapped for a pipe thread plug at correct height in pass side of cover. Access problems solved, though it took some doing, I feel it was worth it.
good luck, gz

btw, they also make the BEST aluminum replacement valve cover, for the 81-86 258, P/N 8656, thing has a screw in O-ring fill cap, BILLET!, and is a true bolt on, (for unmolested heads, anyway). Nice piece of work, pricey, but, made here, ya get what you pay for.
No, I don't work for them! just good stuff.

[MIPS]

I wouldn't of expected a seal somewhere in the axleshaft that separates the lubricants like that but 5 ounces is indeed way less than the entire axle needs. Will it mind if I substitute with 75W-90 synthetic or should I go out and buy another bottle? I actually had the front diff serviced by a shop two months ago so there should already be fresh gear oil. I asked them at the time to verify if the actuator worked specifically because they had to drain it and they said they did and it shifted in and out but I'm here under the car with a vacuum pump and I don't see any indications that it's making an attempt to disengage.

if you don't mind, could you possibly name your source for the front actuator please?  I was hoping to obtain another.

My spare is a junker salvage unfortunately, and even then it needed TLC. There's a vent port that can allow dirt and moisture into the assembly between two of the inner seals. I guess over time dirt and moisture can get in here and seize the shaft. I put some penetrating oil in the vent and actuated the motor by hand while it was clamped in a vice and after a few actuations it operated smoothly.

[amcfool1]

don't know about using the vent hose, that is a VERY small hole, 1/4" , may take a couple of days!  gz

[MIPS]

Well you already said that the axle vent isn't connected to the actuator housing anyways so it wouldn't of mattered lol.

[amcfool1]

should be fine with the lube you have. gz

[amcfool1]

sorry, though you were talking about filling the front diff!  gz

[MIPS]

Okay well that wasn't overly too hard. Loosen the four bolts, tap the side to break the seal and drain the oil into a pan, then remove the bolts and the assembly falls out.




As it turns out, this actuator failed in the same manner as my salvaged one. Seized in the engaged position from junk up the vent.

How do you free it when you are stuck in the ENGAGED (fully extended) position? Put the actuator in a vice as so, then put some penetrating oil (use something that's rubber safe or you'll ruin the seals) around the shaft, give it a minute and then CAREFULLY tap it with a hammer a few times. Don't hit it too hard or else you will break the outer lip of the diaphragm in the jaws of the vice or bend the entire shaft into the bottom of the diaphragm.



Once you see it break free or start to give wrap the shaft in something, clamp it in the vice and push/pull the actuator in and out manually, adding new oil and  forcing more oil down the vent. Brown sludge around the shaft indicates the debris has been broken up and well lubricated. Keep keep cycling oil through and wiling the shaft off here.




Anyways yeah, nice new "rebuilt" unit.



To refill the actuator housing I used a piece of hose clamped to the end of the bottle of oil, then squeezed out as much as I needed and let gravity do the rest.

[Mitch]

Eaglepedia material! Thanks for posting! Thumbs up!