BMW E53 3.0i -- Front&Rear Differential Change + Other various suspension components

[Fifty150hs]

Originally Posted by wpoll

I went down this same path, since full thrust control arms are prohibitively expensive down here (the two Meyle HD bushes cost me $160!). Rebuilding the old ones is an easy job with a press and saves discarding two very large, still serviceable parts of the car.

And if you put poly bushings in you'll never need to replace the thrust arms or service the bushings again.

[e39_touring]

Originally Posted by RocketyMan

Oh wow...I did not know there was a difference in the rear axle flanges. I will deff need to keep a look out for this when I tackle the rear diff next. Luckily it looks like they easily pop out from the carrier, so I can use them from my original. But why the difference?? I wonder the reason.

My only concern is getting the rear cv axles out. They appear to be original and I think they're going to be rusted in the hub. Also, I think i'm going to have to undo the rear control arms some. Or maybe I wont need to? We'll see.

And yeah, I could've done the oil pan gasket too. But from what I see the majority of my oil leaks coming from is the power steering pump. There's a pinch-clamp that straight up drips from. I don't think the valve cover gasket has been done ever, so I plan on doing that when I rebuild the VANOS gaskets. Also, the trans shifter is quite sloppy. You might know about an easy rebuild? Hopefully I don't have to remove the transmission to stiffen the stick?

There is a difference in the rear axles, but all you have to do is pop out the stubs from your original diff and transfer them to the new one. You do not need to pull the whole axles from the rear hubs. Just unbolt them from the stub axles at the differential end.

As others have said, DO NOT drive the vehicle until you change both the front and rear differentials. Otherwise, you may grenade your transfer case since the rear and front shafts will be spinning at wildly different rates.

Regarding the shifter, when you say it's sloppy, do you mean it doesn't return to center and kind of leans over toward 5th? If so, those are the detents I was talking about, and, unfortunately, the tranny does need to come out to replace those. All my bushings turned out to be fine (I replaced anyway), but it was the sticking detents that had me hunting for the gear gates.

Hopefully, your oil pan isn't leaking, but 3 out of the 4 M54 BMW motors I've had developed pan leaks. A thin film of oil would blow all over the bottom of the motor, and I'd get a telltale little drip on the pickup point of the subframe after being parked. This was after all the other fixes - valve cover gasket, oil filter housing gasket, breather system, etc. Was never a lot, but got everything messy under the car and was annoying.

Oh, one other thing, from my earlier comment about tightening suspension. I'm not sure I was clear, but what I meant was the full weight of vehicle has to be resting on its wheels when you tighten everything up in the front. Those bushings do not pivot on the bolt as the suspension moves. The rubber actually twists in the shell.

[andrewwynn]

I use an easier method when tightening "on the ground" bushings: I just use my floor jack to lift the wheel carrier up until that corner just barely lifts off the jack stand. That way I can get that torqued down before even putting the wheel on. ∞ more space to work.

[Clavurion]

Originally Posted by andrewwynn

I use an easier method when tightening "on the ground" bushings: I just use my floor jack to lift the wheel carrier up until that corner just barely lifts off the jack stand. That way I can get that torqued down before even putting the wheel on. ∞ more space to work.

This is what I usually do. But when doing this both sides on stands the stabiliser link can't be connected because if connected you effectively also lift the other side via stabiliser bar so the lifted hub won't be as high as it would with the hubs on the same level.

[RocketyMan]

Originally Posted by e39_touring

There is a difference in the rear axles, but all you have to do is pop out the stubs from your original diff and transfer them to the new one. You do not need to pull the whole axles from the rear hubs. Just unbolt them from the stub axles at the differential end.

As others have said, DO NOT drive the vehicle until you change both the front and rear differentials. Otherwise, you may grenade your transfer case since the rear and front shafts will be spinning at wildly different rates.

Regarding the shifter, when you say it's sloppy, do you mean it doesn't return to center and kind of leans over toward 5th? If so, those are the detents I was talking about, and, unfortunately, the tranny does need to come out to replace those. All my bushings turned out to be fine (I replaced anyway), but it was the sticking detents that had me hunting for the gear gates.

Hopefully, your oil pan isn't leaking, but 3 out of the 4 M54 BMW motors I've had developed pan leaks. A thin film of oil would blow all over the bottom of the motor, and I'd get a telltale little drip on the pickup point of the subframe after being parked. This was after all the other fixes - valve cover gasket, oil filter housing gasket, breather system, etc. Was never a lot, but got everything messy under the car and was annoying.

Oh, one other thing, from my earlier comment about tightening suspension. I'm not sure I was clear, but what I meant was the full weight of vehicle has to be resting on its wheels when you tighten everything up in the front. Those bushings do not pivot on the bolt as the suspension moves. The rubber actually twists in the shell.

So what you're saying is I can simply remove the carrier and there should be enough play in the CV axles to squeeze out the rear carrier without removing them from the hub? That should be awesome and save alot of time.

In terms of the shifter, it's "wiggley" and maybe best to describe it as the "detents" are hard to find or are just sloppy. It doesn't lean over to 5th but feels like something is worn. I guess when comparing it driving a manual e90, the e90 is like super exact detent feeling in comparison.

Originally Posted by Clavurion

This is what I usually do. But when doing this both sides on stands the stabiliser link can't be connected because if connected you effectively also lift the other side via stabiliser bar so the lifted hub won't be as high as it would with the hubs on the same level.

Normally when I tightened suspension components with a rubber type bushing, I usually lifted up the control arm assembly. But now that you mention the sway-bar being connected, that's a good point--it should be disconnected. Otherwise I usually do what @andrewwynn said with lifting the control arm assembly up till it lifts-off the jack stands.

[bcredliner]

Thanks for posting.

I have a set of 4.10 gears for the 4.6 on my garage floor. I think it has been on my yearly mod list since 2017. Thread is inspirational.

Due to the increased torque resulting from the change to 4.10 gearing less fuel is required getting up to speed. It's any sustained speed that hurts mileage since the engine will be at a higher RPMs to be there. Changing to a higher ratio burns more fuel to get up to speed, especially if you want to accelerate at the same rate as before the change. Cruising at the same speed as before will increase mileage.

The opposites can be true depending on the magnitude of the ratio change and whether the engine is running more or less efficiently in high gear. If the change is from a 4.10 ratio and there is no change in the way or where you drive any difference in mileage should be negligible. If you drive a lot of freeway miles the difference in mileage will be higher. The same is true based on how much the ratio changes. If the change were to be something like 3.36 to 4.56, the mileage would noticeably decrease and conversely increase going from the lower to the higher ratio. My experience has been that even a small change in ratio is very noticeable when driving, and noticed anytime you take a drive.

At the going price for a pair of used differentials they are a good performance gain value. If one is into mods it's about how many tenths faster is it to 60 or the eighth or quarter mile.

[Clavurion]

Originally Posted by bcredliner

Due to the increased torque resulting from the change to 4.10 gearing less fuel is required getting up to speed. It's any sustained speed that hurts mileage since the engine will be at a higher RPMs to be there. Changing to a higher ratio burns more fuel to get up to speed, especially if you want to accelerate at the same rate as before the change. Cruising at the same speed as before will increase mileage.

This not that simple. You would have to know the engine's nominal consumption curve and it usually has a sweet spot RPM/load though on naturally aspirated petrol engine anything other than max revs is more or less restricted with pumping losses.

[Happy]

The 3.64’s on an M54 will require more energy (fuel).

[RocketyMan]

Originally Posted by Happy

The 3.64’s on an M54 will require more energy (fuel).

Not true. Very broad understatement. By your logic, everyone should never shift out of first gear then. Which obviously doesn't make sense. You neglect the frictional losses of the engine that are inherent to speed as well as characteristics of a NA engine.

Originally Posted by Clavurion

This not that simple. You would have to know the engine's nominal consumption curve and it usually has a sweet spot RPM/load though on naturally aspirated petrol engine anything other than max revs is more or less restricted with pumping losses.

This is more/or less a correct statement. When calculating fuel mileage, it's fuel used per stroke per unit-distance...or miles per gallon inversely. So by this calculation, you would hold your distance value constant and road-speed constant when comparing different engine speeds between the two loads (two loads because two different "gearing" ratios we're comparing). I've done exactly this when sitting inside a vehicle with a laptop on a dynamometer in various gears. E.G. 55 mph in top gear vs 2nd from top gear. You'll see empirically, with data, that even tho the load is less in 2nd from top gear (due to gearing), the grams-fuel/per-stroke will actually show this, but not in a linear fashion AND ALSO not at the same rate due to engine speed, ergo, to travel the same distance at the same road-speed the engine is doing more revs from a lower gear and thus using more fuel EVEN THO the grams/per-stroke is slightyly less.

That's why Clavurion said there's a "sweet-spot" with this. Because conversely you can't get performance out of an engine by "lugging" it everywhere you go. At the same rate, you can't get efficiency near-redlining the engine everywhere you go.


Hopefully that makes sense.

[RocketyMan]

Here's an update for anyone that's following along. I moved onto the rear differential and I've already loosened three fasteners that hold the carrier to the subframe. There's two in the front with rubber bushing next to the input flange then the last one that bolts up from the carrier's "oil-pan" housing to the subframe. Then lastly I disconnected the cv-driveline. To get to this, I had to undo the left/right exhaust from the center exhaust echo-chamber (I made up this name and I'm going to use it) in order to hang down the heat shielding for cv-driveline flange access.

I will need to get an inverse torx socket from the store tomorrow. I don't have an E10 (I think the size is) to get the cv axles off. Otherwise, I hope the cv-axles will give me enough clearance to just drop the carrier out.

I still have yet to get the thrust rod bushings changed out in the front which I'm hoping to get done at my old boss's.