Differential Swap: Should I Use A Lift or Not?

[73str86]

Preface:

After firing up my high(er) compression L29 with triple SKs, I was so eager to go for a ride that I made it 2.5 miles before realizing I had drained the diff fluid while the motor was being built at the race shop.

Luckily, I have an extremely clean open R180 with 4.11 gears that I found from a guy with a source at salvage lots.

I've read many threads and have searched multiple forums. The FSM seems to say to drop/swap the differential on the ground using jack stands, doesn't it?

I have access to a car lift on base at the self-help garage. Will this make the process any easier? I can also use the lift with the built in transmission jack if needed.

Are there any tricks/lessons learned that may not be seen in most write-ups?

Thanks in advance.

[Zed Head]

Wouldn't it be much easier to just put some fluid in to the diff that's in the car now?

[beermanpete]

I suspect his differential is toast. I tried to move a car without oil in the differential once. It went about 1 block and got so hot is seized. Fortunately, the diff was going to be replaced anyhow so it did not matter.

As for the method of lifting the car, I would prefer to use a service lift as long as I had a suitable jack to lower and raid the differential to avoid dropping it.

[Walter Moore]

I second the motion on having a jack for the differential. The case is cast iron, and it weighs as much, or perhaps more than the transmission. Not something that I would want falling on my head...

[Zed Head]

Didn't realize they'd go bad so quickly. He didn't give any gory destruction details.

I've replaced mine several times using jack stands on the rear only. They're heavy so if you used an auto lift you better be able to maneuver about eighty pounds over your head easily, or have a transmission jack. Doesn't sound like a whole lot but it's an awkward load. On the ground on jack stands you can either bench press it or use a floor jack, balancing carefully. I've always used a floor jack for ease and to stay less greasy, plus it makes it a one man job.

There are basically two ways to do it, leave the mustache bar on and it will drop straight down and go straight back up, or wiggle it forward to release the studs from the mustache bar, and reverse that to install.

[73str86]

Last year my diff was whisper quiet last year while driving. There was a clunk every once in a while during hard shifting, but that's all.

I was coming back from a local team's baseball game. I wanted to take a buddy for a spin. My Dad swore up and down I drained it. I figured my memory was better than his--I was wrong.

I was driving around 25-40 mph for about a mile. Then got on a stretch of 50-70 for a mile and a half. In 4the gear it immediately started a high pitched whine while under load. In about 4 seconds I knew it was the differential. I cursed, and turned around. The 2.5 miles to return home was unbelievably painful. Metal against metal humming is not a good feeling.

I must've had just enough oil in there to last a few minutes. I wanted to cry, but I've since put about 80 miles on the car after refilling the fluid. Now it just hums. I think the bearings are pretty torn up, but it seems to drive ok for local easy driving until I swap it later this week.

Please continue to vote! I plan on dropping it with the mustache bar as mentioned above because it seems a lot smoother.

[Reverend]

I dropped my diffy with half shafts on it, car was on jack stand. Those half shaft bolts were super duper tight on differential end so i had to do it that way. I removed driver side control arm and dropped it, while laying under it. Putting new diffy back is not that PITA if you have extra hands to operate your jack. I was lying under car while my wife operated jack and lifted it up as requested. Took about 10 mins to get it fitted.

I dont see any reason why you should drop mustache bar, unless you are about to change that too.

[cbuczesk]

I'm with Zed Head on just adding fluid. Might as well try that first.

I've swapped diffs many times and might swap one later today. It's pretty quick and easy to put the car on 4 stands and use a jack to lower the diff out. I leave the mustache on the car. The biggest pain is the half shaft nuts.

Chuck

[madkaw]

So you know-good advice above. The diff will pretty much hang off the moustache bar after disconnecting the front of the diff- even without the nuts on there. The r180 is closer to 65lbs - so you can man handle it if your careful. Or balance it on a jack to lower it down.

[Zed Head]

I've always left the mustache bar in, never actually left it attached to the diff, only seen it done that way. Thought it was worth mentioning. As madkaw says, the diff will hang from the two studs in the bar without the nuts, giving time to practice lifting and moving it before bumping it forward it and letting it down.

I've also found that the inner half shaft nuts can be removed using a bunch of extensions on a ratchet handle, working from the wheel well, if you rotate the shaft to the right spot. Leave the outer nuts for last so that you can use the wheel to rotate the shaft.

Also, the half-shaft flange can be a tight press fit on its locating center. You might need a punch or chisel to knock it loose, on the inner and outer sides both. If you use a chisel to split it, make sure that you don't leave any burrs on the surfaces when you put it back together.

In principle, it's pretty simple but there are few spots that you can get stuck at.

[Jarvo2]

No need for a lift...just jackstands & a floorjack will work for you...

[73str86]

Thanks for the tips guys. I filled it with fluid and have been driving it for a week or so--about 180 miles. It still whines but my new parts from Black Dragon for the other R180 arrived so I'll be putting it in within the next couple weeks.