Tips on topping up/filling differential and transmission

[Michael J.]

I have tried some ways of putting that God-awful smelling 70-90 gear lube into these places on a C2, but with so little room to work, I always end up getting it all over my hands, arms, and in the drip pan. Does anyone have a good way of doing this without so much mess? Thanks!

[Gary S.]

Re: Tips on topping up/filling differential and transmission

I just took my 72 out of winter storage and checked all fluids. Yep, had it dripping down my arm and hand. I haven't found a way because the suction gun with 12" hose always leaks past the rubber gasket. I call it a spring rite of passage.

Gary

[Mathew S.]

[Gary R.]

Re: Tips on topping up/filling differential and transmission

I tap a drain plug in all my diff's for easy 10 minute oil changes. Yes, I know it's not correct but so much easier.

You will have to vacuum out the oil as you know. The fill plug is a 3/4 npt thread. If you want to get creative go to Home Depot, Lowes, etc and get some vinyl tubing that will fit over one of those hand pumps that screw on top of a qt bottle of gear oil. Then get a PVC 3/4 plug and drill a hole in it for the tubing to snuggly slide in and deep enough to not pull out. The diff will hold more then you can pump in so add in 2 bottles of GM LS additive, and pump in close to 2 qt of oil, depending on how much you got out to start.

NOTE - the 63 to early 65's used a machine thread before they switched to the 3/4 npt thread.

[Michael J.]

Re: Tips on topping up/filling differential and transmission

Thanks for the help guys, I think I need to find a better pump. One that doesn't leak and the hose doesn't come off when you are pumping.

[Frank D.]

Re: Tips on topping up/filling differential and transmission

I use the large extraction pump shown (about $60 on Amazon) to vacuum fluids out of my boat, jet ski and Corvettes for years; including oil, tranny/differential fluid, you-name-it. No muss, no fuss. The cheap hand pump (second pic) is what I use on Amsoil bottles to install fluids - again, clean and quick (around $9 IIRC).

[Larry M.]

Re: Tips on topping up/filling differential and transmission

Mike:

I use a funnel and a length of clear Tygon tubing (hardware store). Tubing is probably 1/2 inch ID x 5/8 inch OD and attaches to my funnel.

I then put the hose into the trans fill hole or differential fill hole and fill from either the engine compartment (trans) or the passenger wheel wheel (differential). I put a pan under item I am filling in case I overfill.

Then I simply POUR the fluid into the funnel and it gravity drains into the trans/diff. Very easy and no suction guns.

I either use a suction gun or simply syphon drain the trans and differential using a short piece of the same tubing. Insert and pull a vacuum initially with a "battery filler rubber bulb" or other suction device. Again very easy to do...........although draining is best done in warm weather or with fluid warmed up a bit to speed draining.

FWIW.

Larry

[David P.]

Re: Tips on topping up/filling differential and transmission

Try a MightVac MV6400. If you need to vacuum it out you can use the MV7430. They also make one that does both.

[Michael J.]

Re: Tips on topping up/filling differential and transmission

Thanks all, those are all really god suggestions I will try next time.

[Terry D.]

Re: Tips on topping up/filling differential and transmission

Frank
Where did you get the cheap hand pump?

[Frank D.]

Re: Tips on topping up/filling differential and transmission

Frank
Where did you get the cheap hand pump?

Here: https://www.amsoil.com/shop/by-produ...tle-hand-pump/

Can't say if it fits every bottle from different vendors but its easy enough to poor whatever you have into an AmSoil bottle and then you're good to go. Once you use this you'll forget all about long tubes and cramming funnels down beside the bellhousing and other such antics.

[Edward B.]

Re: Tips on topping up/filling differential and transmission

I've always liked the aroma of gear lubricant, but it can be messy. My refilling is done with a funnel and clear tubing. It always helps to measure the fluid before pouring to an amount a little less than the capacity stated in the manual so as not to overfill; simply pouring from the bottle almost guarantees spillage.

[Richard G.]

Re: Tips on topping up/filling differential and transmission

I recently replaced the wheel bearings on a 73. The oil was so bad in the differential I pulled the differential to change the oil. It was so thick there was no way to suck it out. After changing the fluid my clothes stunk so bad my wife threatened to not let me in the house. Garage stunk for a week. Clean 90W can be stinky to some. 45 year old gear oil/tar is just awful.
Rick