marlinspike

Anybody have any experience with this?
http://www.superior-transmission.com...Page.cfm?ID=20

I'm making significantly more power than MB intended my car have (uses same trans as you 928 guys, just not as a transaxle). As a result, I was left with two choices: max out the vac modulator and get a 2-3 WOT throttle shift that bucks, or back it off an get one that slips. I updated the K1 piston to the new version and it cured it, until ambient temps came down enough for my car to make more power to the point where I now have the same choice to make. This kit seems to offer a few different springs for varying degrees of shift firmness, but I have no idea what the quality is. Anybody know anything about the company? What would happen if the spring broke while the car was being driven?

marlinspike

Really? Nobody? Well, I guess I'll be the first and report back.

Landseer

Not even I was awake between the time of your posts to answer on sunday morning.

Yes, it is said that a spring kit will help. JHowell did it to his 4 speed auto trans. Somewhere in my PM's is buried the part number(s). Think they were MB parts.

You really mean a new upgraded B2 piston, right? If not, please post more details / pics of this K1 change.

marlinspike

I did the B2 piston and I guess what I should have said is I did the K1 spring upgrade, not piston upgrade. MB 126 270 44 77. My understanding is these aftermarket springs I linked to are even stiffer.

Landseer

I need to hear how it works. I've got one that has flare between 2 and 3 also.

And a second one that just started doing it with a new modulator valve. Increasing pressure firmed it up a bit, but it needs more, though the 1/2 shift is almost too stout.

marlinspike

So you weren't familiar with the MB factory K1 spring update either? I didn't want to waste your time thinking it was just confusion over my saying piston and not spring.

Here's a write up on the factory K1 spring update. IIRC MB went to this new spring when they came out with the 560.
http://w123maintenance.blogspot.com/...ement-and.html

If it's simply a flaring it will work, but if the car kicks in and out of gear a couple times apparently that's a sign of enough excess power that the MB kit will only work in warm ambient temps (when your engine is down on power). That's the theory I've come up with anyway.

So did yours not start doing it until you replaced the modulator valve? If so, which modulator did you go to? I kinda think mine didn't start doing it until I went to the new modulator (the newest one being red and all plastic) also (but am not 100% certain). I've heard Porsche still sells the old modulator (old ones being either green or red with a metal band) and was thinking about going to one of those.

Landseer

I was, but its been a couple years since researching it. Thanks for the reference.

The biggest area of mystery for most of us close-to-uber-enthusiasts is the transmission.

I'm one of the few that's messed with them, totally disassembling, swapping... but not understanding or rebuilding one yet. Its the next huge failure point looming on the cars. The manuals are more difficult it seems due to very expensive parts. At least the auto has common parts for the most part. ( So to speak)

Please add whatever you can to the knowledge here! We need this.

marlinspike

Will do. It's been a pretty happy coincidence for me that my car uses the same trans (except not as a transaxle) as a Porsche 928. I don't think there'd ever have been aftermarket springs for it without that.

There are a few halfway decent pdfs floating around out there on 722 transmissions, though sadly only on different versions than the versions we have. They're still similar enough to give you a general idea. I have them on a hard drive...somewhere....

For when I do find them, how can I link to a pdf?

tommi nylund

I have this shift kit with modified torque converter and I like it very much!

I put the most hardest springs from the kit to my transmission. At first it was maybe even too hard, it really hammered the gears in...but a slight tweak of the control pressure made the trick for me.

Would highly recommend to everyone who are suffering gear change problems.

It involves the removal of a valve body, so you have to be EXTREMELY careful not to lose any those small ***** and other stuff when (if) you take the bottom plate out of the valve body. But after that it is relatively easy work. When you take the valve body out of your gearbox IIRC there was nothing you can lost, just when (if) you take the bottom plate out of the body, then there are few small pieces which position you need to know in order to put everything in place again.

And it was the gas -model kit I have.

marlinspike

You had to remove the valve body? When I changed out the K1 spring in my car wth the updated MB spring I did it with the valve body in the car, just dropped the pan and removed the screwplate that covers the spring. I guess while the transaxle placement Porsche chose is better for handling, MB made the box to be serviced in a traditional location.

Landseer

Here are some pictures, can you describe further using these?

marlinspike

I haven't ordered it yet. It's extremely cold and I'm going to be moving to a place soon where I can actually work in the garage rather than outside in an apartment complex parking lot. If someone can figure out how I can put a pdf online, I'll post up the instruction sheet.

Landseer

Take a digital photo of it, even if on the screen of the computer, and post as a picture

marlinspike

You gave me an idea when you said "screen"...good ol' print screen
http://davidson.smugmug.com/Cars/tra...14979457_46zpJ

tommi nylund

Yes, you have to remove the valve body because some of the spring assemblies are too long to be removed with valve body on place.

I don't have any detailed information other than follow the instructions which came with the spring kit. It will tell you what and where.

If you lost the location of any small parts between the valve body and the plate, then you'll have to check their positions from either Porsche or MB WSM.