Need to swap the diff....!!!! - PeachParts Mercedes-Benz Forum

vwbuge · #1 10-24-2007, 12:03 PM

I was driving around in the rain last night. I was ascending a pretty big hill near my house at about 40mph. Next thing I know I was sideways! I learned a while ago that I had a non-LSD. Since I installed the boost controller it got a little dangerous. Another line on my "to do" list.

dieseldiehard · #2 10-24-2007, 12:18 PM

What size and type of tires are you running on it? Are you implying you are going to install an LSD diff?
I would live with the existing 2.88 diff. You are going to spend big bucks on a LSD, I believe the one in a 6.9 may fit but isn't the same ratio so the speedo will have to be recalibrated.
One should control acceleration with your right foot when you are driving under slippery conditions, don't let boost come on hard. The '85 has an edge over earlier turbodiesels in that the vacuum "flying saucer" modulator improved the trans shifts with respect to boost. Once in a while my '85 300D will break traction and its always when wet or on pine needles. the '87s however are entirely different, almost like a gasser, in that torque comes on hard when you are full throttle!

I've even chirped tires on a hot day with 1-2 shift. 603's rule!

d.delano · #3 10-24-2007, 12:24 PM

Quote:

Originally Posted by vwbuge

I was driving around in the rain last night. I was ascending a pretty big hill near my house at about 40mph. Next thing I know I was sideways! I learned a while ago that I had a non-LSD. Since I installed the boost controller it got a little dangerous. Another line on my "to do" list.

LOL stop driving around on bald tires and stop speeding in the wet. You have a non-LSD because MB engineers decided your diesel with all of 123hp at the crank doesn't need an LSD because it's not a 560SEL AMG. Nothing dangerous about a regular differential, this is why they are in 95% of the cars on the road.

pawoSD · #4 10-24-2007, 12:34 PM

I agree, most likely what happened was your BALD or LOW quality tires hydroplaned or slipped due to the water on the road. I can just barely break my (expensive high quality) tires free in the wet from a standing start (punching the throttle), there's no way they'd come loose at 40mph in the rain if I floored it. Yeah right.

The only way they're coming loose at that speed is with the brakes.

Spend the $$ on new tires, not a new differential. And, don't drive so hard in the rain!

And, with the 2.88, you have even less chance of breaking them loose than with a 3.07 like most of us have.

vwbuge · #5 10-24-2007, 12:43 PM

Quote:

Originally Posted by pawoSD

I agree, most likely what happened was your BALD or LOW quality tires hydroplaned or slipped due to the water on the road. I can just barely break my (expensive high quality) tires free in the wet from a standing start (punching the throttle), there's no way they'd come loose at 40mph in the rain if I floored it. Yeah right.

The only way they're coming loose at that speed is with the brakes.

Spend the $$ on new tires, not a new differential. And, don't drive so hard in the rain!

And, with the 2.88, you have even less chance of breaking them loose than with a 3.07 like most of us have.

I am not driving on BALD or LOW QUALITY tires. I was under the impression that maybe my car was ordered with a non-LSD rear. I was also under the impression that most SD's came with LSD rears.

I also disagree that 95% of the cars on the road have non-LSD rears. I am not saying my car is some kind of powerhouse but I often chirp the tires between shifts. I thought all along that this was related to the rear not being a posi-traction or LSD.

Also, I do not drive like a maniac with my foot in the car all the time.

My brother in laws old SD went like a tank in the snow. My car can't even get out of its own way with a heavy dusting of wet snow on the ground.

Ara T. · #6 10-24-2007, 12:51 PM

Your tranny is shifting too hard and/or your tires suck if it breaks loose in the wet. Mine would go nuts on a 1-2 full throttle shift when it was nice and slick out. Changing your diff wont help.

vstech · #7 10-24-2007, 01:47 PM

actually, I would bet the ratio of open to LS diffs is more like 99% if you take out all the TRUE sports cars, it would be closer to 99.999% that said, modern "Smart" vehicles have an electronic lsd system built into the computer... not the same as sport car positraction, but like a hydrolic/electronic limited slip, also tied in is the throttle to cut back on boost/fuel during hazardous conditions.
My SD is quite spirited, it will break loose on turns, hills, etc. even on dry pavement. it all depends on what RPM you shift gears at and how hard the shift is. a hill with running water on it during a shift from 35 or so to downshift for more climbing power could easily cause a sideways condition... the solution is NOT TO FLOOR IT GOING UP A HILL IN THE RAIN>>>

winmutt · #8 10-24-2007, 03:17 PM

SD's did not EVER have LSD from the factory. Some of the bigger SE and SEL's did. Good luck in find it on the lot.

Just get bigger tires. Running 235 and I have to work it to break grip.

vwbuge · #9 10-24-2007, 05:11 PM

I will try the wider tires and definately go with a different brand next time.

thanks for the advice.

I stand corrected on the LSD thing. I always assumed differently. It is amazing how I posted a simple statement (misinformed statement) and everyone jumped on my rear assuming that I am like a 16 year old. Driving with bald tires and floorting it every chance I get. You guys are disappointing at times.

rrgrassi · #10 10-24-2007, 05:16 PM

I would rather be accused of driving like a 16 y/o than an old fart.

Sounds like you may have hydroplaned a bit. I have BFG tires, and they are really dicey when the pavement is wet. Thay are now due for replacement, and I am looking into Michelin or Pirelli.

peterhardie · #11 10-24-2007, 05:38 PM

I have Toyo's and can break them free on wet pavement. I have wondered whether it is the tires. I could do it (less frequently ) with the auto trans, much easier to do with a stick. I try not to accelerate on turns on hills in the wet.

I run 205-70-15's. I also have the 2.88 in the rear. Same horses in the front.

rrgrassi · #12 10-24-2007, 05:44 PM

I want 15's. I have the 14 bundts.

vwbuge · #13 10-24-2007, 11:57 PM

I actually went to a 16" wheel. I have 225/60-16 on now. I'll see if I can fit something a little wider.

t walgamuth · #14 10-25-2007, 04:41 AM

Actually the wider tires will hydroplane quicker than a narrow tire. IMHO a 225 is wider than I would want, for this and many other reasons.

With lsd you will actually go sideways quicker if you get both tires hydroplaning. Actually with hydroplaning, it doesn't matter how good your tires are, excepting of course that if they are bald of course they will hydroplane at a heavy dew!

Yeah, the guys were a little rough tonight, I thought too.

Tom W

peterhardie · #15 10-25-2007, 05:49 AM

I like the look of wider tires aestetically, but for traction (except in mud maybe), skinnier is better. Pure physics: friction. I get the skinniest snows I can fit.

Tall vs short is another story. Taller rims offer better handling (less sidewall action) but are usually wider. I had 16's on my wagon loved the handling in the dry, and the look. Decided it was not worth paying $$$ for tires in that size, especially having two sets of tires for winter and summer.

I think Tom is right, it seems more than a few of us have gotten 123s and 126's to spin the rear tires. It does not reflect on the driver or his tires.Your width may be your problem, vwbuge, but maybe not. I got 195's to spin on wet flat pavement. With a bad tranny at that!