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+--- Thread: Diff. Ring gear sizes? (/showthread.php?tid=452)
Diff. Ring gear sizes? - 2.5-10 - 06-24-2009
hello all,
does anyone know the ring gear size in a 240D diff.? 115 or 123, should be the same I'd think.
or a late model 560 SEL?
I'm trying to figure out if my 240D has a big enough gearset to take the torque from the 560's motor
Thanks much.
-Erik
RE: Diff. Ring gear sizes? - winmutt - 06-24-2009
(06-24-2009, 06:10 PM)2.5-10 I'm trying to figure out if my 240D has a big enough gearset to take the torque from the 560's motor
No, you will need the bigger drivetrain. The most immediate failure with the 240 setup would be the flex disks.
RE: Diff. Ring gear sizes? - ForcedInduction - 06-24-2009
The V8s use bigger flanges and flex discs. That V8 would be screaming down the highway with a 3.69! It would get to 120 real quick though.
RE: Diff. Ring gear sizes? - 2.5-10 - 06-24-2009
(06-24-2009, 07:30 PM)winmutt(06-24-2009, 06:10 PM)2.5-10 I'm trying to figure out if my 240D has a big enough gearset to take the torque from the 560's motor
No, you will need the bigger drivetrain. The most immediate failure with the 240 setup would be the flex disks.
(06-24-2009, 08:09 PM)ForcedInduction The V8s use bigger flanges and flex discs. That V8 would be screaming down the highway with a 3.69! It would get to 120 real quick though.
I'll be using a 560 flex disc with a custom driveshaft trans -> diff, I just want to know if the 240's gear set can take the 300+hp and 320lb/ft this motor will be putting down, and if it cant, whats a beefy dif that will direct bolt to the W115?
I have no problem with 3.69 gears, I want good mileage even if its a little bogged down off the line
RE: Diff. Ring gear sizes? - 2.5-10 - 06-26-2009
anyone know the ring gear size? is the 300D diff stronger? will a W201 diff bolt up, will my late model W126 diff bolt up?
I need it to take about 350LB/FT torque
RE: Diff. Ring gear sizes? - SurfRodder - 06-26-2009
the ring gear size is 185mm... the one in your 560 is 210mm... if you want to swap to the larger one, I know that an early(pre-1985) w126 diff will bolt up to the ass-end of the w123... and by leaving it with the 3.69, it will have better off the line performance, but not have as much top end potential, which also means not as good mileage potential... the good news is that the gear ratio in the 560 is 'used to' is probably the same one the early w126 v8s used, 2.47...
all that said, I doubt that you'd bust that 185mm diff unless you were doing power launches all the time, i.e. drag racing, but I do understand the urge to make sure it'll hold up...350lbf is a bit, but probably well within the capacity of the 185mm(~7.3") diff, now if you were looking to modify that engine for more power, def. go with the larger one.
anyway, if you want to hit up the yards, look for 1985 and older w126s with a v8 and crawl underneath and check the ratio that is stamped on the housing(flat spot on the bottom left edge of the face where the diff cover bolts on) it should be 2.47:1 which I think is still what they were running in the later models, either way, the v8 will have more than adequate power to push it...and if you have looked at enough diffs, youll notice right away that it is a bit larger than the w123...
the 300D will have the same diff, just numerically lower (taller) gears...201 and late model diffs wont bolt up, it may be possible to modify a later 126 rear subframe to fit the 123, and then the later 126 diff will work(let me know if you do that!) you can also swap the guts of the same size diffs around, but youll likely need a shop to set it up for you (apparently MB diffs are really difficult to set up properly w/o the right tools... im still gonna try it anyway)
RE: Diff. Ring gear sizes? - 2.5-10 - 06-26-2009
I knew the W126 gasser diffs were 210mm sets, I was just unclear if the 85 and earlier were actually different mounting. good to know if and when I blow up the diff.
do I stll use the W115 axles with the 201mm diff?
also, does anyone know if the motor mount spacing in the W114/W115 is the same as the W123?
RE: Diff. Ring gear sizes? - DeliveryValve - 06-26-2009
Yes use the w115 axles. Just make sure you have the correct spacer in the diff.
You have many other options besides the 123 or 126 if you can find one that suites your needs. Any differential from a 107, 114, 115, 116, 123 and 126 would swap, up to 9/85.
RE: Diff. Ring gear sizes? - SurfRodder - 06-27-2009
(06-26-2009, 02:56 PM)DeliveryValve Any differential from a 107, 114, 115, 116, 123 and 126 would swap, up to 9/85.
thats really good to know... which ones of those had the 210mm gear? i wanna keep an eye out for certain ratios...
(06-26-2009, 02:56 PM)2.5-10 also, does anyone know if the motor mount spacing in the W114/W115 is the same as the W123?
im not sure... someone else prolly does.
RE: Diff. Ring gear sizes? - 2.5-10 - 06-28-2009
(06-26-2009, 02:56 PM)DeliveryValve Yes use the w115 axles. Just make sure you have the correct spacer in the diff.
You have many other options besides the 123 or 126 if you can find one that suites your needs. Any differential from a 107, 114, 115, 116, 123 and 126 would swap, up to 9/85.
good to know, hopefully we wont blow the gear set on the 185mm diff that quick
(06-27-2009, 01:49 PM)SurfRodder(06-26-2009, 02:56 PM)DeliveryValve Any differential from a 107, 114, 115, 116, 123 and 126 would swap, up to 9/85.
thats really good to know... which ones of those had the 210mm gear? i wanna keep an eye out for certain ratios...
(06-26-2009, 02:56 PM)2.5-10 also, does anyone know if the motor mount spacing in the W114/W115 is the same as the W123?
im not sure... someone else prolly does.
I would think only the V8 versions of those chassis would have the 210mm gears.
and I'll hope that someone will chime in on the motor mount spacing
RE: Diff. Ring gear sizes? - GREASY_BEAST - 06-28-2009
(06-26-2009, 09:48 AM)SurfRodder the 300D will have the same diff, just numerically lower (taller) gears...201 and late model diffs wont bolt up, it may be possible to modify a later 126 rear subframe to fit the 123, and then the later 126 diff will work(let me know if you do that!) you can also swap the guts of the same size diffs around, but youll likely need a shop to set it up for you (apparently MB diffs are really difficult to set up properly w/o the right tools... im still gonna try it anyway)
Pre-1985 V8 cars have a 2.47 diff that bolts to the W123 subframe. I know because I have one. All you have to do is swap the input shaft, or not if you are building a custom driveshaft.
RE: Diff. Ring gear sizes? - 2.5-10 - 06-28-2009
if I start with the 115 (123) diff, will I need to get a new custom drive shaft to mate up with the 85 or before V8 126 diff?
RE: Diff. Ring gear sizes? - DeliveryValve - 06-28-2009
(06-28-2009, 01:52 PM)2.5-10(06-27-2009, 01:49 PM)SurfRodder(06-26-2009, 02:56 PM)DeliveryValve Any differential from a 107, 114, 115, 116, 123 and 126 would swap, up to 9/85.
thats really good to know... which ones of those had the 210mm gear? i wanna keep an eye out for certain ratios...
I would think only the V8 versions of those chassis would have the 210mm gears.
I would assume that is correct from 1972 and newer. The factory cut off point from the 185mm gear in a 1.1 liter case to the 210mm gear in a 1.3 liter case is at 200 horsepower. Everything with over 200 horsepower has the larger 210mm ring gear in the 1.3 liter case.
(06-28-2009, 05:17 PM)2.5-10 if I start with the 115 (123) diff, will I need to get a new custom drive shaft to mate up with the 85 or before V8 126 diff?
As stated earlier, you'll just need to change out the pinion/input flange that fits your driveshaft or make a custom shaft to fit the V8 126 style pinion/input flange.
.
RE: Diff. Ring gear sizes? - 2.5-10 - 07-15-2009
I just popped under the car, and I must say I am confused looking at the axles, the CV boots and mounts look very strange, hex bolts?
do they still pull straight out like they do on my toyota?
RE: Diff. Ring gear sizes? - SurfRodder - 07-15-2009
are you referring to how to disconnect the axles? If so, you need to drain the diff and pop the back cover off. then you rotate the axles until you can see a C-clip, which will have a little ear that you can grab with some pliers and pull out. As for the outboard end, theres a standard hex bolt (10mm head, me thinks) that you need to take out.. then you should have enough wiggle room to get 'em out...
also note: before you remove the drain plug on the diff, ensure that you can fill it (remove the fill plug on top first)
RE: Diff. Ring gear sizes? - winmutt - 07-15-2009
13mm on the outside.
RE: Diff. Ring gear sizes? - 2.5-10 - 07-15-2009
(07-15-2009, 05:27 PM)SurfRodder are you referring to how to disconnect the axles? If so, you need to drain the diff and pop the back cover off. then you rotate the axles until you can see a C-clip, which will have a little ear that you can grab with some pliers and pull out. As for the outboard end, theres a standard hex bolt (10mm head, me thinks) that you need to take out.. then you should have enough wiggle room to get 'em out...
also note: before you remove the drain plug on the diff, ensure that you can fill it (remove the fill plug on top first)
oh, wow - thats ridiculous! I'll just stick with my 183mm gearset
560 motor is going in the /8 within the week.
(07-15-2009, 06:02 PM)winmutt 13mm on the outside.
hopefully I wont need to swap to a 210mm
RE: Diff. Ring gear sizes? - DeliveryValve - 07-15-2009
(07-15-2009, 09:56 AM)2.5-10 I just popped under the car, and I must say I am confused looking at the axles, the CV boots and mounts look very strange, hex bolts?
do they still pull straight out like they do on my toyota?
I think what you are looking at is called an Annular Axle. This axles can be separated at the flange which is installed in the differential. You can tell by the cap/hex bolts by the inner joint.
The good thing about these axles is that you don't have to take the diff cover off to remove the axles.
The other axles that came on Mercedes before 1986 is called Homokinetic.
They are distinguished by having similar cans on the inner and outer sides.
You will have to remove the diff cover and get at the "C" clip to remove the axle.
Both Annular and Homokinetic axles are interchangeable.... as long as you have the flange part on the Annular axle.
Here is a pic from FI's differentials. The diff on the left has Annular Axles as noted by the flanges on the sides and the cover is still intact. The diff on the right used the Homokinetic axles. You can see he had to remove the cover to get the axles out.
.
RE: Diff. Ring gear sizes? - 2.5-10 - 07-16-2009
my 560 has annular for sure which is no surprise as its post 86, I havent looked at my /8 but I would guess it has the other type.
if I were to ever need to upgrade to a 85 gasser diff from a 126, would I need to get a new drive shaft? is the diff. casing the same width on the 183, and the 210 gearsets?
could I use the /8 183mm axles with a 85 126 gasser diff? what about my custom driveshaft?
RE: Diff. Ring gear sizes? - SurfRodder - 07-16-2009
(07-16-2009, 12:07 AM)2.5-10 if I were to ever need to upgrade to a 85 gasser diff from a 126, would I need to get a new drive shaft? is the diff. casing the same width on the 183, and the 210 gearsets?no, but you would need to swap input flanges on the diff in that case
yes, the 185 and 210mm diff casings are same width
(07-16-2009, 12:07 AM)2.5-10 could I use the /8 183mm axles with a 85 126 gasser diff? what about my custom driveshaft?the axles that came with the car you are putting the diff into should be what you need...
what custom driveshaft? /specs?
RE: Diff. Ring gear sizes? - 2.5-10 - 07-16-2009
(07-16-2009, 01:15 AM)SurfRodder(07-16-2009, 12:07 AM)2.5-10 if I were to ever need to upgrade to a 85 gasser diff from a 126, would I need to get a new drive shaft? is the diff. casing the same width on the 183, and the 210 gearsets?no, but you would need to swap input flanges on the diff in that case
yes, the 185 and 210mm diff casings are same width
input flange is different on the 183mm diff than it is in the 85 gasser diff? do swap that, I would assume I would have to partiall disassemble both differentials correct?
(07-16-2009, 12:07 AM)2.5-10 could I use the /8 183mm axles with a 85 126 gasser diff? what about my custom driveshaft?the axles that came with the car you are putting the diff into should be what you need...
what custom driveshaft? /specs?
I see, I just would hate to have to spend more $$ to get my already expensive drive shaft shortened or lengthened, since the 722.350 transmission is a bit bigger than the 4-speed manual
i sure hope the oil pan on the M117 clears the subframe on the /8
RE: Diff. Ring gear sizes? - DeliveryValve - 07-16-2009
(07-16-2009, 12:07 AM)2.5-10 ....
if I were to ever need to upgrade to a 85 gasser diff from a 126, would I need to get a new drive shaft? .... what about my custom driveshaft?
If your going to make a custom driveshaft, I would keep the 126 gasser diff flange because it is stronger.
.
RE: Diff. Ring gear sizes? - 2.5-10 - 07-16-2009
I'll be getting one made if I cant find a MB one that fits properly, the flex discs are hardly any bigger on the 560, very weird
RE: Diff. Ring gear sizes? - SurfRodder - 07-21-2009
(07-16-2009, 05:14 PM)2.5-10 I'll be getting one made if I cant find a MB one that fits properly, the flex discs are hardly any bigger on the 560, very weird
yeah...just enough to screw up a perfect fit...