2funnn

I am planning on changing the Diff. oil on my 92 (Dana 44) and my wife's
94(Dana 36). Have any of you drilled and tapped the housing for a drain plug?
I am thinking of doing that and wanted your advice.
I am a machinist so I know how to do things like that.
Thanks in advance! :chevy

JAKE

I'm not familar with your year but on the 86 there is a screw-in plug on the passenger side of the housing.

Once removed guys usually install a small suction pump and pump it out. Removing the rear cover is a real PIA.

When I changed mine I used the pump out method and added a bottle of Posi-Lube from GM's parts department.

If yours doesn't have a removable plug, I guess you only have two options: remove the rear cover or drill and tap for a plug.

I'm sure you know that with the drill and tap method you've got to be concerned with metal shavings.

Maybe someone else that has the same year car as you will chime in.

Hope this helps.

Jake

Rich B.

I'm pretty close to doing the same thing; drill & tap in-place, let the runoff oil clean the hole...Tap it...Then dump a quart of 10w30 in the diff to clean out the threads...(let it run right out through the new drain)...

Now, you brought up another option: D&T the diff or the cover??? (Well, what passes for a cover)...

My only concern (hey, it's only aluminum! It won't harm hardened steel gears/bearings even if a piece does get loose!) is how thick the bottom of the diff casting is...Too thin, and I won't be able to thread it...

RichS

I was debating on doing this as well but wondered about causing a stress point for a crack. Then the rear goes boom :smash:

Oly

When I changed the differential fluid in mine, I used a suction pump to remove all the old gear oil. I refilled it using the specified GM differential lube and remember to add the GM limited slip differential additive. It's not a difficult procedure.

CROOZN

All dana 36's and 44's have an inspection plug on pass. side of car. I WOULD NOT DRILL AND TAP FOR A DRAIN PLUG! You use a hand pump to remove old gear oil. I used 1 bottle of posi additive and filled it up with 85w140 until it just leaked from the inspection hole. Of course the car was level. I change mine every year or 5,000 miles.

2funnn

Croozn, is there a reason for running 85w-140? My factory manual recommends
80w-90 GL5.
I think I will just use a suction pump to get the oil out.
Thanks! :flag

h rocks

I did mine when we put the .373's in a few years ago. It was easy to see where to do it with it apart, but Mid Am has a kit for doing it on the car. There's also a techique that utilizes one of the bottom bolt holes for a drain, but you definitely need to have the diff apart to do it. I did the fill hole/pump thing too many times, and was going to do it either way. I got tired of trying to remove *that* whale _ _ss smell off of me for a week every time I changed the fluid. To address some comments and concerns, the diff housing is very substantial. (thick) If you saw a competition rear end, you would be surprised at how many additional holes are drilled and tapped for the lines to the fluid cooler. Go for it.

nickd

This is what I'm planning on using to change my fluid: http://www.harborfreight.com/cpi/cta...emnumber=30287
or http://www.harborfreight.com/cpi/cta...emnumber=37739

Goody

Before I installed my Dana44 I drilled out the bottom bolt hole from the inside. Now all I do is remove the bottom bolt and let it drain out. Reinstall with some thread sealant so it doesn't leak. :D

silver & red CE

Which side of the case did you install it in (driver's or passenger)? What size bolt did you use?


[Modified by silver & red CE, 5:43 PM 1/7/2002]

6spd89

I have that Harbor freight pump an d it is GREAT!!!! I have not used on my Diff. though. It should work, that thing SUCKS HARD!!!LOL. I use it for radiator fluid mainly,just transfer into a clean container and back in when you
need to .Sure beats draining the radiator.
Matt

royzee

Reading your thread back in 2002, I have a 95 C4 Dana44 dif. and wondering where best to locate a drain hole without removing the rear cover. Can U help me?

Thanks,
RoyZ

toptechx6

See post #4 in this thread:

http://forums.corvetteforum.com/c4-t...questions.html

j-wireman

I have thought of doing this, myself. How about drilling and tapping for a magnetic oil drain plug (I have a spare)? Worth the extra effort or overkill? Just wondering.

royzee

wireman, after about 10K the rear gears will be meshed-in to where no additional metal wear should occur - on my other cars I have always drained ~ 10K, flushed using hot mineral oil, inserting a small tube/hose into the diff. to sparge air in and mix the contents (10-15 psig) then drain well B4 refilling with final fluids. Thereafter I maintain changes each 50K but have never found metallics in the used oil after the initial 10K clean out - but - I DO NOT RACE MY CARS - THEY ARE DRIVEN QUITE SANELY HOWEVER THROTTLED NOW AND THEN. The drain location shown by toptechx6 is close to the ring gear and I would be hesitant to install an extended magnet plug into that area.

HlhnEast

Wow we have a winnah!!!!!! I think this is the oldest thread dragged back from the dead I have seen. Generally its OK to start a new thread about what you want to talk about instead of posting a reply to a TEN YEAR OLD POST. Gotta commend you for using the search function tho.

Mods generally will close it if they see it........so...........IBTL