Pete L

My 86 5 speed with LSD no longer has the “spring force” that is needed to pull the shift lever to the left and back to get into first. The lever is now just loose / floppy in the neutral position and easily moves left to right. It takes the same force in the parallel direction of the car / torque tube to shift from 1st to 2nd and 2nd to 3rd etc. as it always has. The reverse lock out still operates

The car is shifting fine but is really hard to accurately downshift from 4th to 3rd for example (wants to go to 1st) . I am assuming that the one of the springs on the internal selector rod (#13 lockout spring or #12 the U Spring has come loose. Can anybody with knowledge of this comment / advise.

One other question. Does removal of the internal selector rod require its removal in the direction of the differential (per 34.14 step 4 in WSP). Simply asking since if the fix is simply repair / replace the spring, could be “easy” to remove the top case cover after dropping the transmission, remove the roll pins from the rod and move it forward (toward the from the car) to install new spring / springs

Thanks

GregBBRD

Wrong drawing, for your transmission. That's an '83/'84 transmission.

In your year, there's a flat spring which provides the spring pressure side to side. That is what is broken. Three different versions of that spring, from 1985-1995, along with two versions of the roller that touches the spring. The roller/spring interface is extremely important and the fact that Porsche superceeded the spring without telling everyone that the roller must be changed at the same time, broke hundreds of these springs....shortly after they were installed during a rebuild.

None of the three versions of the spring are currently available. A couple of people have attempted to build these springs, but they didn't appear like they would function for extended periods of time (questionable material choices.) I'm currently using the very last of the used springs I have left over from "core transmissions" for my own rebuilds, which is a really poor thing to have to do. I can warranty everything I do inside these transmissions, except this spring....and the damage it does when it breaks.

The important thing, right now, is for you to get the broken end piece out of your transmission. It will eventually get caught up by the gears and will turn the inside of that transmission into scrap metal. Remove the drain plug and start fishing with a magnet.

Pete L

Greg

I just ordered the Mobile gear oil to swap out the old, will start to fish to find the piece. Provided I find it, ok to drive other then crappy shifting (downshifting?)
Shucks

928NOOBIE

When my transmission was fixed last November we did an overhaul...this same spring Greg mentions (its literally a flat piece of metal...there's something on one end..can't remember now what it is...a slot of another small piece of metal...) was cracked and nearly broken. They repaired it (not sure how)...but I was told same thing...these things break...

hacker-pschorr

Some good installation tips in this thread:

https://rennlist.com/forums/928-foru...g-install.html

davek9

I purchased a spring from Roger that was made by a fellow Reenlister, cost was ~$250 bucks, along with the Reverse Lockout spring (that was broken too) from Porsche, another ~250 bucks, can you say ouch!!!

The main thing as Greg points out is to get the broken bits out of the Transmission, especially if you are going to go around corners fast or like doing donuts as when the oil is hot those broken bits will fly around and get into the (most likely) reverse gear set as it's the lowest and chip off some teeth, BTDT

My first 928 the '85 had 60k miles on it back in '97 when I purchased it this spring was broken, I repaired it back then, it was my first big 928 job, still holding up too.

I have yet to install the new parts I recently purchased as noted in that other thread, I'm going to swap the box w/ a known good unit and rebuild the broken one as time permits.

Dave K

Edit: that other thread shows a way to "measure" a Tension for the spring, the manual shows using a Spring tension gauge and pulling on the shift lever, so the exact way to set the spring tension depends on MY of the trans.

Pete L

I drained the gear oil and found the broken head of the spring

Presume that the c clip will keep the arm attached to the stud ?

Photo of broken spring and drain plugs (more metal that anticipated). Expect this was due to the some 20 odd track days and several poorly executed heel toe downshifts at Willow Springs big track

Replaced gear oil with 100% Redline NS. Use 2 quarts of 75/90 and two quarts of 75/140. Noticeable improvement on shifting quality

GregBBRD

For that piece to come out, the torsion part of the spring has to crack and generally break off. I'd keep fishing, until I was positive there are no more chunks.

Yes, the '85 transmissions had a circlip to hold the bottom portion of the torsion spring in place, should the spring fail. The remainder will stay there, harmlessly, because of that circlip.

The downside of the circlip is that you have to be a Ninja to get the circlip off to change the spring, without removing the entire input shaft.

Pete L

Updated on my broken flat / centering spring in my 1986 (early) 5 speed with 171K mile.

Per Gregs post above, I drained the Redline MT out of the transmission and fished around again with my magnet and borescope. I found no other pieces of the “flat spring” For photo of the unbroken spring in another thread, see here https://rennlist.com/forums/928-foru...g-install.html I presume my spring looks like that broken spring head in post #43

I used to always keep the transmission in reverse when I parked it and suppose this contributed to its failure (per PorKen post in the above referenced thread) by placing more pressure on the spring

Greg Brown made the comment in the thread “Actually not very difficult to make an external shifting spring that works off of the shift coupler.... it’s just a bit complex.” I came up with a simple solution that seems to work, at least on a 928s Rus short shifter. A photo of my accessory spring that is now duplicating the function of the old flat / centering spring is included.
The transmission, at least to me is shifting the same as it was before.

No flames please. I will ultimately rebuild the gear box and fix correctly, but this seems to be working pretty darn well, I had to buy several additional springs and am happy to send for cost of shipping to anybody else who want to try this

ROG100

Colin "Lizard" makes these springs and I sell them. Lots installed with zero issues over the last 10 years.

Pete L - way to go on the fix.