722.3 Modifications

[jhodg5ck]

Hello Everyone,
I did a bit of searching and didn't come up w/ much so I thought I would ask what (if anything) can be done to a 722.350 to beef it up? I'm planning on SC'ing my car and want the trans going in to be as robust as possible.

I'm also pondering adapting a 722.5 and saving the 5th for just cruising on the highway, but again, I want to upgrade the core (722.3) of the box as much as possible.

Thanks!
Jonathan

[jhodg5ck]

Nobody here know's these boxes very well, eh?

Jonathan

[gsxr]

What car would this be for?

You can build a 722.3 to be plenty strong, they're used behind the SL600's V12 engine. All it takes is money.

I posted about the 722.5 tranny swap elsewhere, search for the thread... short version is that it would be quite expensive (probably $3-$4k, even with used parts), a huge amount of work, and the 722.5 has a poor reputation for reliability. I have been dreaming about this though, it would allow a nice 3.27 rear end instead of my anemic 2.65...

BTW - you get my last email about the EPC & ODUS?

[jhodg5ck]

Hey there Dave,
I know it can be done, I was just wondering if people knew exactly what was done;-) I was speaking w/ my trans rebuilder (mb only) and he'll build a 722.5 for about 900.
I'm going to need a diff. drive shaft as well as setting up a switch to control the 5th gear etc.. so there will be some added cost, but I have a friend that deals a Lot w/ a custom drive shaft house.

My understanding is the 5th gear on these boxes (overdrive really) is not the most robust thing out there.. Thus my thought to keep it for highway crusing only. If the day comes when I'm shifting at redline from 4th-5th, I imagine it will be a once in a lifetime affair... I know that the bell housings will fit (one alignment dowel needs to be modded a bit) and I beleive there is a enough space under there for the unit, so it Should be ok..


As far as a diff goes, I would like a 3.27, but it looks like I may be able to fit the 3.07's from a 450SL into our case, I'll have to get my hands on one and take it from there.

And yup, I got it, I have your package all ready to go out!

Jonathan

[gsxr]

I wanted to put the 722.5 into a W124, which was a factory offering in other countries. The Euro EPC provides the part numbers needed. Certain SL's are valid donors for most of the used parts. You should be able to locate the driveshaft pieces used, no need to fabricate anything. Of course all the Euro shift lever parts will be required, either from Euro breakers, or new from Speed-Autoteile.com.

I'm less sure about putting this tranny into other chassis, and also the electronics portion. I don't know if a simple switch would work, or be very user friendly. I'd rather have it automated. I'm also concerned about longevity behind an intercooled turbodiesel with 250+ lb-ft of torque. (!)

There are a number of rear end options, I'd go for the 3.27 LSD from a 190E-16v since it's mostly a bolt-in swap for a 124. I'm interested in finding someone who can convert a standard/open diff to LSD for a reasonable cost, too, if you know of anyone. I may never attempt the 5-speed project, and if not, I may settle for a 2.87 or 2.82 limited-slip rear, depending on if I use the 'small' 124 diff or the later 'medium' 129 diff. I'm working on a differential interchange spreadsheet to determine which cars would be the best donors.

Here's the 5-speed auto thread:
5-speed AUTO upgrade for W124?


Oh, thanks btw - I'll shoot you an email about that other thing.

[jhodg5ck]

You very well may be right on the drive shaft issue, I imagine once I get a length down there is prob. an MB shaft out there that will do.

I don't want to make my automaticly go into 5th as I don't want to use it unless I'm on the highway. I plan on supercharging my SEC and I do Not want to be shifting into 5th unless I have too (that whole durability thing..). Plus, that way my car will look bone stock on the inside which is what I like.
I saw an add on craigs list out in SF of a fellow who was parting out a 16V not a month or so ago..you might want to poke around see if he still has tthat diff..!

I forgot about posting those images, I'll start the uploading right now

Jonathan