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View Full Version : 1990 325is auto- diff


Ceeker
03-28-2009, 04:16 PM
Could anyone tell me if the diff( LSD) on a 90 325is auto is different from a 5 speed (LSD)?

thx

5thseries
03-28-2009, 05:43 PM
Yes it is different

the auto dif is 4:10
manual diff is 3:75
(LSD)

///Mmm
03-28-2009, 06:36 PM
Yes it is different

the auto dif is 4:10
manual diff is 3:75
(LSD)

It's 3.73 to be specific hehe

Ceeker
03-28-2009, 06:45 PM
did all auto 325is's come with a 4:10 diff? I'm assuming because it is an "IS" that it has limited slip. unlike the 318is.

Thx.

ZiMMie
03-28-2009, 06:51 PM
did all auto 325is's come with a 4:10 diff? I'm assuming because it is an "IS" that it has limited slip. unlike the 318is.

Thx.

it depends on what date the car was manuf.

5thseries
03-28-2009, 07:05 PM
It's 3.73 to be specific hehe

;)*uzi*

everlast
03-28-2009, 07:30 PM
You also had the choice of ordering a diff of your liking to some degree. Good way to check is to run the VIN, better way is to jack up the rear end, spin the tires and count the number of times the driveshaft turns.

Edit: That is, unless the metal tag is still on the back of the diff of course. Then just read it.

matty.dc
03-28-2009, 08:00 PM
along the same lines....is a 325is 1987 auto a 4.10 diff?

craz azn
03-28-2009, 08:41 PM
Didn't you just ask this exact same question a few days ago?

Ceeker
03-28-2009, 08:59 PM
I think so...my guess would be because the auto response is slower so it would need a taller diff to give it pick up.

craz azn
03-28-2009, 09:06 PM
No, again, you don't seem to understand the terminology with this gear ratio thing. It needs a SHORTER diff to help the 'pick up' as you say. Not taller. Taller = longer = lower number.

5thseries
03-28-2009, 09:11 PM
along the same lines....is a 325is 1987 auto a 4.10 diff?No, e30s from 1989 and up are 4:10. so no.

craz azn
03-28-2009, 09:32 PM
No, e30s from 1989 and up are 4:10. so no.

Righto. Actually, I believe its 9/87+ when the autos came with 4.10s. But I'd have to look that up to be 100%.

W2WDETAILING
04-19-2009, 12:14 AM
Righto. Actually, I believe its 9/87+ when the autos came with 4.10s. But I'd have to look that up to be 100%.


sweet so i guess my plans to upgrade to a 4:10 diff are out the window since i have one :)

Ceeker
04-19-2009, 12:47 AM
auto's 4:10 5sp 3:73. I got a 4:10 in my auto and a 3:73 in my 5sp. Even a 325i/4dr 5speed had a 3:73. Lsd-or at least the one I switched into my 318is was one.

echo
04-19-2009, 12:51 AM
You can change the ratio of the LSD's to anything you like using the crown and pnion gears from a non-LSD of the desired ratio.

If you are not 100% comfortable doing this get a reputable diff specialist to do it as you must ensure you have the preload etc set correctly on the LSD.

But if you already have a medium case LSD, just buy any el-cheapo open medium case diff and pull out the crown and pinion gears.

W2WDETAILING
04-19-2009, 12:52 AM
auto's 4:10 5sp 3:73. I got a 4:10 in my auto and a 3:73 in my 5sp. Even a 325i/4dr 5speed had a 3:73. Lsd-or at least the one I switched into my 318is was one.


nice i have been trying to figure out what diff i had i have a 90' 325i 4dooor auto, build date 89/11

Eurostyle
04-19-2009, 02:10 AM
sweet so i guess my plans to upgrade to a 4:10 diff are out the window since i have one :)

BUT you can upgrade to a low milage 4:44 that i have in stock!*th-up* Will give you better "off the line" acceleration, with a bit less top end. *wave*

W2WDETAILING
04-19-2009, 02:55 AM
BUT you can upgrade to a low milage 4:44 that i have in stock!*th-up* Will give you better "off the line" acceleration, with a bit less top end. *wave*
NICE but only one problem i drive on the highway way too much and that would kill my gas and i would get in trouble and need to replace my tires every week*shiner*

Eurostyle
04-19-2009, 03:14 AM
NICE but only one problem i drive on the highway way too much and that would kill my gas and i would get in trouble and need to replace my tires every week*shiner*

At 100-130Km/h, you might need $5 more every week, if that! Remember this car was made to run on european highways at 200+...so even with a high ratio you are still good on our roads!

W2WDETAILING
04-19-2009, 03:19 AM
At 100-130Km/h, you might need $5 more every week, if that! Remember this car was made to run on european highways at 200+...so even with a high ratio you are still good on our roads!

hmmmm...i am sending you a msg!