WELDED DIFF ?

WhiteOne · 08-13-2008, 02:08 PM

Do they tack the ring gear to the diff?
Do they weld it solid?
Why can't you just add a LSD and a new ring gear?
What is a welded diff?
If this has been covered, I apologise.

jeremyc74 · 08-13-2008, 03:09 PM

When I saw this thread title I thought someone was considering making the "backwoods locker" by welding the spider gears together. I'm glad to see that's not the case!

I think they weld the spider gears to the end of the axles, but I'm not sure.

m3gtrdtm · 08-13-2008, 03:40 PM

DO IT.

ThunderRobo · 08-13-2008, 07:57 PM

Quote:

Originally Posted by WhiteOne

Do they tack the ring gear to the diff?
Do they weld it solid?
Why can't you just add a LSD and a new ring gear?
What is a welded diff?
If this has been covered, I apologise.

in essence, being welded means nothing moves inside the diff, the only thing that gives is the tires, wheel on the left rear will move at the same speed as the right rear at all times unless the diff fails.

you will feel a push from cornering (that also means understeer is lurking tryin to getcha)
help smoothn out some bumpy roads
help you get up high entrance/entries (instead of doin the one wheel burnout)
expect a lot of tire chirping

Not very drivable ion the streets. are you dragging the car?

larryn · 08-13-2008, 08:27 PM

If our diffs are welded from the factory (cannot use a Quaiffe), then these two gears are welded together, making it impossible for an aftermarket diff to be installed in the same housing:

Btw, Advevo (a Dutch 1Addicts member) confirmed that his 135i had a welded diff.

larryn · 08-13-2008, 08:37 PM

Here's a pic of the welded version of the same diff:

WhiteOne · 08-13-2008, 08:58 PM

Looks like they welded the ring gear to the diff in the second picture. Ring gear looks bolted on in the first picture. If that is all they did why can't you install a Quaife with a new ring gear? Am I missing something? A mechanic I'm not.(Yoda talk)

larryn · 08-13-2008, 09:01 PM

Quaifes bolt onto the inner flange. Notice that doesn't exist on the welded one. The welded one cannot be taken apart to insert a Quaife, and even if you could, there's nothing to bolt it to.

adc · 08-14-2008, 01:35 PM

Quote:

Originally Posted by larryn

Quaifes bolt onto the inner flange. Notice that doesn't exist on the welded one. The welded one cannot be taken apart to insert a Quaife, and even if you could, there's nothing to bolt it to.

So how about a new OEM inner flange, with bolt holes in it? I think that was his question...

(You've probably noticed I'm not an expert... :biggrin: )

larryn · 08-14-2008, 01:39 PM

I'm pretty sure that you cannot remove the welded gear assembly without destroying the diff case. I certainly wouldn't want to use a cutting torch to get the existing gears out.

The E9X guys pretty much had to buy a entire diff, if they found that they had a welded version. Those fortunate enough to have a non-welded one can use a Quaife-like LSD replacement in the existing Diff case.

jeremyc74 · 08-14-2008, 02:03 PM

Thanks for the pics Larry. That clears it up quiet a bit.

Having worked in a shop that made gears, I can see the advantage of the welded setup from an OEM point of view.

In normal (bolted together) setups, the ring and carrier are complete finished parts that get bolted together. Any imprefections that are in the two mating machined surfaces get passed on to the actual teeth. On top of that, the torque on the bolts is pretty critical. I'm betting that with this welded setup the teeth are cut (hobbed and shaved) with the two peices welded together, which would produce a very true gear, while eliminating a very critical step in the manufacturing process.

It's an interesting idea. It certainly sucks for us though.

F0Bman · 08-19-2008, 02:00 AM

Welded diff always a bad idea. Might as well find out if you can put a spool in there.

1erich · 08-19-2008, 10:44 AM

How many older 335i's would be in pick-a-part lots already?

jeremyc74 · 08-19-2008, 11:05 AM

Quote:

Originally Posted by F0Bman

Welded diff always a bad idea. Might as well find out if you can put a spool in there.

He's not talking about welding it solid. He's talking about the fact they they come welded together from the factory and you can't take them apart to put in an LSD. You have to change the entire housing.

adc · 08-19-2008, 12:28 PM

Quote:

Originally Posted by 1erich

How many older 335i's would be in pick-a-part lots already?

The housing is different in the 3.

08-13-2008, 02:08 PM	#1
WhiteOne Major 28 Rep 1,000 Posts Drives: 2008 AW 135i Join Date: Dec 2007 Location: Alabama iTrader: (0)	WELDED DIFF ? Do they tack the ring gear to the diff? Do they weld it solid? Why can't you just add a LSD and a new ring gear? What is a welded diff? If this has been covered, I apologise.
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08-13-2008, 03:09 PM	#2
jeremyc74 Banned 76 Rep 5,970 Posts Drives: '08 135i Montego/Terra Join Date: Feb 2008 Location: Evansville, IN iTrader: (0)	When I saw this thread title I thought someone was considering making the "backwoods locker" by welding the spider gears together. I'm glad to see that's not the case! I think they weld the spider gears to the end of the axles, but I'm not sure.
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08-13-2008, 03:40 PM	#3
m3gtrdtm Private 3 Rep 56 Posts Drives: AW 135i Join Date: May 2008 Location: Charleston, SC iTrader: (0)	DO IT.
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08-13-2008, 08:27 PM	#5
larryn Lieutenant General 2148 Rep 10,176 Posts Drives: '97 332ti, '21 X5 45e, '16 GT4 Join Date: May 2005 Location: Seattle iTrader: (2)	If our diffs are welded from the factory (cannot use a Quaiffe), then these two gears are welded together, making it impossible for an aftermarket diff to be installed in the same housing: Btw, Advevo (a Dutch 1Addicts member) confirmed that his 135i had a welded diff.
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08-13-2008, 08:37 PM	#6
larryn Lieutenant General 2148 Rep 10,176 Posts Drives: '97 332ti, '21 X5 45e, '16 GT4 Join Date: May 2005 Location: Seattle iTrader: (2)	Here's a pic of the welded version of the same diff:
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08-13-2008, 08:58 PM	#7
WhiteOne Major 28 Rep 1,000 Posts Drives: 2008 AW 135i Join Date: Dec 2007 Location: Alabama iTrader: (0)	Looks like they welded the ring gear to the diff in the second picture. Ring gear looks bolted on in the first picture. If that is all they did why can't you install a Quaife with a new ring gear? Am I missing something? A mechanic I'm not.(Yoda talk)
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08-13-2008, 09:01 PM	#8
larryn Lieutenant General 2148 Rep 10,176 Posts Drives: '97 332ti, '21 X5 45e, '16 GT4 Join Date: May 2005 Location: Seattle iTrader: (2)	Quaifes bolt onto the inner flange. Notice that doesn't exist on the welded one. The welded one cannot be taken apart to insert a Quaife, and even if you could, there's nothing to bolt it to.
	Appreciate 0 Quote

08-14-2008, 01:39 PM	#10
larryn Lieutenant General 2148 Rep 10,176 Posts Drives: '97 332ti, '21 X5 45e, '16 GT4 Join Date: May 2005 Location: Seattle iTrader: (2)	I'm pretty sure that you cannot remove the welded gear assembly without destroying the diff case. I certainly wouldn't want to use a cutting torch to get the existing gears out. The E9X guys pretty much had to buy a entire diff, if they found that they had a welded version. Those fortunate enough to have a non-welded one can use a Quaife-like LSD replacement in the existing Diff case.
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08-14-2008, 02:03 PM	#11
jeremyc74 Banned 76 Rep 5,970 Posts Drives: '08 135i Montego/Terra Join Date: Feb 2008 Location: Evansville, IN iTrader: (0)	Thanks for the pics Larry. That clears it up quiet a bit. Having worked in a shop that made gears, I can see the advantage of the welded setup from an OEM point of view. In normal (bolted together) setups, the ring and carrier are complete finished parts that get bolted together. Any imprefections that are in the two mating machined surfaces get passed on to the actual teeth. On top of that, the torque on the bolts is pretty critical. I'm betting that with this welded setup the teeth are cut (hobbed and shaved) with the two peices welded together, which would produce a very true gear, while eliminating a very critical step in the manufacturing process. It's an interesting idea. It certainly sucks for us though.
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08-19-2008, 02:00 AM	#12
F0Bman First Lieutenant 3 Rep 309 Posts Drives: Join Date: Apr 2008 iTrader: (0)	Welded diff always a bad idea. Might as well find out if you can put a spool in there. __________________ Fully Restored 1985 Corolla GT-S 1987 328ci SR20DET Drift Car 1989 Honda Civic Si-R Current Project 2002 Corolla CE Daily Driver www.TheTunerSource.com
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08-19-2008, 10:44 AM	#13
1erich Second Lieutenant 4 Rep 244 Posts Drives: 09 135i Join Date: Jul 2007 Location: Calgary iTrader: (0)	How many older 335i's would be in pick-a-part lots already?
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