There is no drain plug for the differential in our 85 Regal. I do have a devise that is designed to suck out fluid from things. Is this the best/easiest way to change the gear lubricant in the differential? I really don't want to take things apart if I don't have to.
Thanks
Jim

Lotsa differentials require the rear cap to be removed to change the lubricant. It ain't a bad idea. It allows complete drainage, allows you to see how much metal has been ground off your gears, & gives you the opportunity to check the condition of the mechanical parts. But it isn't neat.

You can suck the fluid out through the filler plug, but you can't get it all. It's a reasonable solution if you're having no problems, & the old gear lube isn't contaminated. A lot of shiny little sparkles in the old lube suggests the desirability of removing the cap for a further check.

There is usually a lot of gunk in the bottom that needs to be removed. This can only be done with the cover off.

All Barths are not the same. How many bolts does yours have? 10 or 14?

Here is some info for 10-bolt people:

Mine has a 10-bolt Dana 60 or 70 diff. The cover gaskets are the same for either, according to the aftermarket cover sellers. My spare gasket has 34687 on it. Google showed some rather tenuous conversions to 2952471 and 929877, both of which convert to NAPA pn FPG RDS60951.

Clickie

However, when I do a search for my year P30, the only ten-bolt cover gasket that shows up is FPG RDS6014 1984 Chevrolet Truck P30 1 Ton - Step Van Engines : 7.4 L 454 CID V8 w/ 10 Bolt Holes;w/ Spicer/Dana 70HD Axle

https://www.napaonline.com/Sea...101984+50014+2014076

The pictures look pretty much the same.

Just checked at NAPA, and they are both Fel Pro, both the same dimensions, but one is blue, the other black. The blue one is six-something and the black (6014) is ten-something. Autozone and Checker Kragen Shucks both list both numbers, but you might have to order. The RDS60951 is $3.99 at both.

The cover has ten bolts with 9/16” heads

If you have a ten-bolter, and think it will help, I can send you a tracing of my spare gasket to get you started.

Some folks use silicone rubber, but it works better with cast covers than with stamped. If you elect to use silicone rubber, use Permatex and try to make the cover as flat as you can. I glue a sheet of coarse Wetordry to a glass plate and rub it around until the marks show full contact. There might be high spots at the bolt holes, so a little hammer work can help.

Be sure you refill perfectly level left to right, as this also is your wheel bearing lube. It is a good idea to recheck after a little driving.

I replaced my diffy cap with one from Mag-Hytec (did the transmission, too. The have a drain, and a magnetic pickup (which I couldn't use, because my diffy is inverted).

Thanks Bill & Rusty ours is a 10 bolt. Your template would be a help Bill.
Thanks

quote:

Originally posted by Jim and Tere:
Your template would be a help Bill.
Thanks

OK. I'll get it out Monday.

quote:

Originally posted by bill h:

quote:

Originally posted by Jim and Tere:
Your template would be a help Bill.
Thanks

OK. I'll get it out Monday.

PM me with your US Snail addy

PS note updates on pns in earlier post.

Bill,
Thanks. Rec'd template. It's a match.