Will this LSD fit in my 525i?

[DanDombrowski]

I put a bid in on this LSD for my 93 525i (5 spd). I may have bid too soon, because I have just realized that it says in the auction that there are two different drive shaft lengths, but does not go into specifics.

Does anyone know either if this LSD will fit, or if not, how I would find out if it would fit?

Here is the link:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1,1&item=8040361076&sspagename=STRK%3AMEBI%3AIT

[gale]

It will bolt in as-is. The only difference with the input flange is for a manual vs. auto. The manual uses 6x 10 mm studs and is a bit shorter as he says. The auto uses 6x 8mm studs and is a bit longer as he says. If you're swapping a manual with a manual, it's a direct fit. It's when you get into the 750/850 M5, e34 v-8 diff's that there are more incompatability issues with non-M 6-cyl e34's.

[DanDombrowski]

Oh man, thank you for telling me what I want to hear! Seriously, thank you for replying with relevant info.

I have no idea what my diff ratio is. I tried to get under there once, but totally couldn't read the tag. I suppose I need to try again. If I remember correctly, the 3.73 is a relatively low-geared diff right? I'd like to keep it low, as I can do relatively quick 1/4 mile times, and am hoping this will make it better. At the same time, I don't want to go any lower, as I'm already at 3,000 rpm at 67mph.

[gale]

According to Vine's chart, yours would have a 3.23. A 3.73 would be a nice boost for the lowend without causing it to rev too high at higher speeds. I'm running a 3.91 LSD in mine and it's the most I'd want to go with a 5-spd. I have a 3.64 that's been sitting on the bench for over a year and I haven't put it in since the 3.91 is so d@mn much fun! :D

http://www.vinesauto.com/diffratio.htm

[632 Regal]

beware of the front flange swap!

http://www.bimmer.info/~regal632/Rear%20end%20write%20up.txt

[DanDombrowski]

So you're telling me that if I were to swap the input flange (for use in an automatic, or if it were from an automatic that I would have to swap to a manual input flange) that I would have to set the preload correctly?

Assuming manual-manual swap, I don't have to change the input flange, and I don't have to worry about all that?

Thank you Jeff, this is exactly the type of caveat to swapping in an LSD I'm looking for.

[632 Regal]

youll need a new pinion crush coller and know a little about preload. I guessed at preload but have built a few dozen rear ends over the years, Im sure there is an inch lb setting for preload but thats also with the ring gear removed so it wouldnt be accurate.

The part about marking the position of the bolt only works if you replace the same flange, with a different flange your outta luck.

Personally I would hold out and find a bolt in option instead of playing russian roulet.

just my 2c

[ryan roopnarine]

here's a thread wherein i asked where the tag was (involving the late allan s)http://www.bimmer.info/forum/showthread.php?t=5451&highlight=diff+tag

as he suggested, you MUST clean the thing off if you expect to find it. you'll just look over it if you don't. the tag is the little "blade" looking thing in the pic i took.

[Toeks]

what exactly does the LSD do? And how would I know if my car has it or not?

[DanDombrowski]

Jeff,

I'm really confused now. I thought I WAS getting a bolt in option, becuase it came from a manual and my car is a manual no swap was needed.

Am I wrong?

[gale]

what exactly does the LSD do? And how would I know if my car has it or not?

LSD as in "Limited-Slip Differential" refers to a locking differential which has friction/clutch plates in the differential which deliver torque to both axles in the event that one wheel loses traction (helpful in snow/ice, loose gravel, etc., also good for the track for accelerating out of corners).

There are several ways to verify if you have one:

1. look for an "S" in front of the ratio tag on the back diff cover

2. raise both rear wheels off the ground with the brake off and in neutral and give the wheels a spin. If they both rotate in the same direction, it has LSD, if opposite directions, then it's an "open" or non-LDS.

3. raise only one rear wheel with the brake off and in neutral. Try to rotate that wheel. If it rotates freely, it has an open diff. If it won't rotate or takes significant effort (on the order of 100 ft-lbs) to rotated it, it's LSD . . .

. . . as opposed to:

"LSD (lysergic acid diethylamide) one of the major drugs making up the hallucinogen class. LSD was discovered in 1938 and is one of the most potent mood-changing chemicals. It is manufactured from lysergic acid, which is found in ergot, a fungus that grows on rye and other grains."

[gale]

Jeff,

I'm really confused now. I thought I WAS getting a bolt in option, becuase it came from a manual and my car is a manual no swap was needed.

Am I wrong?

Not to worry, manual-to-manual, it's a direct match, no need to swap the input hub.

[Toeks]

and there I was thinking my car is what the Beatles were singing about all those years ago;Lucy in the Sky with Diamonds.

Thanks for the explanation, as soon as I can jack the car up, I'll have a look.

[632 Regal]

well dan...when I got my LSD unit the front flange was swapped to the correct one, so they say. It was the wrong flange and my indy swapped it, he also noticed the side flanges were wrong too so I put the old ones on, didnt like the splines so I had to use a big hammer to get them to "slip" on.

With that all being said there are more than just 2 input flanges, theres two bigger manual ones that have 2 different bolt hole sizes, there is at LEAST 2 different smaller auto trans too, there are at least 2 different side flanges too.

I know this doesnt help you but it's a nice thing to know instead of getting the big surprize.


Jeff,

I'm really confused now. I thought I WAS getting a bolt in option, becuase it came from a manual and my car is a manual no swap was needed.

Am I wrong?

[632 Regal]

looked at the unit for sale, looks nice and "should" bolt in. Its pretty much a luck of the draw if you cant compare them side by side. Id assume that one will fit but you will be the first to figure that part out. I'm sure you could sell it if its incorrect and then provide the info about the flanges.

[DanDombrowski]

Well, if thats the best I'm going to be able to do, then thats the best I can do. Jeff, I really appreciate the help, this is exactly the kind of thing I was looking out for.

Hopefully it will, if not, we'll have a warning for future buyers.

Thanks for all the help guys! I won the auction ($265 shipped), I'll be putting it in real soon, right after:

Oil change in the Camry
Timing belt and oil pump seal on camry
O2 sensor replacement on eclipse
O2 sensor and backpressure test on the honda
Engine belts and bushings on the Volvo

Yay for maintenance!