300d rear diff question - PeachParts Mercedes-Benz Forum

#1 02-12-2006, 04:57 PM

I have a 1984 300D turbo with a bad rear. i have a chance to buy a rear fron a 1981 300D non turbo cheap, are the gear ratios different ?
thanks

slowmike · #2 02-12-2006, 06:17 PM

for a post by Brian Carlton on 1-9-06. Something like '2.24/2.47 final drive'. I think he posted a list of differential ratios for several vehicles. I think the 300D's all had 3.46 ratios.

mike

Brian Carlton · #3 02-12-2006, 06:51 PM

The '81 has a 3.46.

Your '84 has a 3.07.

You don't want the 3.46 in the turbo 123. It doesn't even need the 3.07, preferring a 2.88 or even a 2.47 by some folks.

I've put the 2.88 in the SD and I believe it's the perfect combination.

slowmike · #4 02-12-2006, 07:21 PM

for clearing that up. I found the list I'd copied from that post but it didn't list a difference between turbo and non-turbo. Glad you set things straight.

mike

#5 02-12-2006, 07:34 PM

thanks for clearing that up.
if i wanted to build the 81 rear up with the 2;88 GEARS, where would i find the parts to do this ?

#6 02-12-2006, 07:37 PM

FYI, this lists the ratios for all the W123s:

http://www.adsitco.com/category.asp?CID=416

Brian Carlton · #7 02-12-2006, 07:37 PM

Quote:

Originally Posted by mb1982

thanks for clearing that up.
if i wanted to build the 81 rear up with the 2;88 GEARS, where would i find the parts to do this ?

Those are a bit rare. You need to find a 1985 vehicle. It's the only one with the stock 2.88.

pawoSD · #8 02-12-2006, 09:34 PM

The dealers sell the 2.88 gears as replacement for the 3.07's, we checked this out at our stealer. So you could just go there for some brand new 2.88 differential innards.

I think they said it was about $900 for all the components.

Brian Carlton · #9 02-12-2006, 09:49 PM

Quote:

Originally Posted by pawoSD

I think they said it was about $900 for all the components.

#10 02-13-2006, 07:47 AM

thanks, ill see if i can find a 1985 2:88 or ill settle on another 3:07 rear
again thanks

t walgamuth · #11 02-13-2006, 07:57 AM

why not just find a used 288 (or 247 for that matter) and put it in. these mb diffs hardly ever wear out (are you sure yours is worn out?). installing the diff in your car is lots easier than changing the gears. and you can prob find a diff for 2 or 300.

the only mb diff that i ever saw worn out was when someone put different sized tires on the back and drove and drove and drove and boiled the grease out of it.

i would check it some more to determine what is causing your symptoms. good chance it is not the diff.

btw, what are your symptoms?

tom w

#12 02-13-2006, 08:50 AM

Thanks, my problem is when i take off or declerate, like if im comming to a stop sign i hear a loud clunk.
i figgured that if i bought a good used diff went over everything at work did what i had to do, and installed the rear in my car over the weekend
i would'nt tie the car up very long.

t walgamuth · #13 02-13-2006, 08:55 AM

are you sure the clunk is from the diff?

if the diff is causing it you should be able to put the car in neutral, and grab the driveshaft near the diff and twist back and forth. a small amount of play is normal but if there is a lot then you have a pinion problem. if the pinion if bad there will probably be leakage around the pinion seal too. also if it is really bad the pinion will be loose up and down.

like i said, i have had nearly 30 old benzes in my life so far and never a problem with a diff. i had one fail in a suburban i had though. well, wore it out. i replaced it before it failed.

tom w

rudolfgreen · #14 02-13-2006, 03:17 PM

are there any differences between the 2.47 diff's in the 380 or 500 when putting into a 123?

#15 02-13-2006, 03:21 PM

i like the idea of using those stiff highway gears, where could i buy just the ring and pinion