Fluid Extraction vs Draining

[SR77]

Hello, I am going to need to change the oil in my Rams Front and Rear differencials soon and wanted to get some opinions on using an oil extractor to remove the gear oil versus going through the process of taking the covers off to drain the oil.

Some thoughs I had on this are Pulling the covers will get every last drop out, but I also run the risk of future cover leaks if it does not seal perfectly when reinstalled. This also seems like the longer process of the two. Drilling and tapping these covers with a drain plug seems like a good idea, but having never done this before, it seems alittle risky for my daily driver.

For extraction, this may not get every last drop out, but will be a faster and less messy job to do. Less chance of a future leak.

Please let me know what your opinions are on this and any other advantages or disadvantages I may be missing.

PS: For any of you that have used an extractor before, which ones are DIYer affordable and will still be able to pull 140 weight gear oil? Good thing about an extractor is I could potentially use it on other parts too like the transfer case, trans etc. thanks

 

[JHZR2]

I've used an extractor in my saab's my because the drain plug is stuck behind a suspension member.

It worked fine.

I'd use a liquivac with the green plastic container. I'd extract it from the trick hot. For refill, get a big fluid gun which will easily fill a 140wt lube. You want two different devices for the two halves of the job.

The extractor to pull the fluid from the diff should have a very small and flexible hose that you can work around the inside. To fill, the syringe gun should have a big hose to ease suction and release.

 

[Rand]

if its the first change I'd take them off if possible.
There is usually a large amount of gray/silvery crud in there.

if its not the first change or they are behind suspension components and the covers are not easily removable fluid extraction is a decent alternative.

 

[mechtech2]

You are light years ahead of the game if you change it by suction, vs. leaving the old stuff in. Well OK... at least you are going in the right direction. This is often a good choice.

But, as you know, there will be debris left in. Most that I've seen kinda aggregates and rests - just sits there.
Replacing a cover is no big deal. It is small and easily cleaned. Use a good silicone RTV on CLEAN surfaces, give it time to set up, and refill.
Remember you are only going to do this once , maybe twice in the life of the vehicle.

 

[01rangerxl]

Popping the inspection cover off won't get every drop of oil out unless you let it sit for a long time. There's still oil in the axle tubes and on the gears. Spraying with a solvent like brake cleaner can help clean the gears off and allows you the opportunity to inspect the condition of the differential, but if you spray the gears down you want to be sure all that solvent is drained out or dry before you put the cover on and refill.

It's kind of hard to mess up putting the diff cover back on and leaks are unlikely unless you really botch the gasket install, be it RTV or paper. I have used Permatex Ultra Black for years now with no leaks ever.

That said, there's nothing wrong with extraction either and it is more than enough to keep diffs in excellent shape for the life of the vehicle. It will make the job easier, but if you want to look at the diff and get it as clean as possible, go ahead and pop the cover. It's really not so bad.

 

[AandPDan]

RTV works fine. They aren't under pressure. You can find gaskets for some covers if you choose.

Pop the covers. You WILL find a lot of junk in there, especially if you have an LSD.

Is the rear a 9.25"? Check for broken clutch pack retainers in the bottom. They can wear a groove in the carrier housing.

 

[bdcardinal]

My opinion, do both. Extract as much fluid as you can out the fill hole and then pop the cover off. There will be less fluid dumping out all over the place, and you can check and clean the internals.

 

[HTSS_TR]

Originally Posted By: bdcardinal
My opinion, do both. Extract as much fluid as you can out the fill hole and then pop the cover off. There will be less fluid dumping out all over the place, and you can check and clean the internals.

I agree.

I did just that last weekend when I need to replace the transmission pan gasket.

I used Mityvac to extract 3.5-3.6 quarts from the fill hole, when I removed the drain pan there was almost nothing in the pan but ATF keeps dripping down into it, I let it drips for more than 1 hour, the total in the pan was about 1/2 quarts.

 

[artificialist]

Remove the pan and blast off the gray slime with brake cleaner. RTV is not a problem if you properly clean both surfaces, and give the RTV the proper amount of time to cure before you refill with new gear oil.

 

[WMSmotorhead]

There's usually some junk settled in the bottom, so popping the cover off to clean it out is the better option.

 

[SR77]

thanks or all the replys.

For those of you that use extractors, what is a good affordable DIYer extractor that won't break the bank, but still works well and will pull thick 140 weight gear oil.
thanks again for all the help

 

[meep]

search on amazon, I picked up a new mityvac for ~$60. worth. it.

just used it today...

M

 

[HTSS_TR]

One of the best that doesn't cost a lot is Mityvac 7201 from Aamzon for around $8x. I have 1 since 2004 and still work well extracting oil, ATF, brake bleeding ...