915 transmission problem

[raven1700]

At time my transmission won't let me into 1st, 2nd and on a rare occasion 3rd. My porsche dealer said that I had to switch the gear sets, and syncro rings and hubs. Also in this same transmission I can't downshift from any gear to 1st, unless speed is below 5mph and reverse is difficult to get into at times. Please help, what could be wrong?

[azasadny]

I'd start by inspecting and possibly replacing your shifter bushings. Mine were just replaced and the tranny shifts like never before! Smooth and precise in every gear and that's not bad for a 32 year old 915!

[Oh Haha]

Yup. Check your bushings first. I can't go into first over 5mph and my gearbox was rebuild a couple of years ago.
How many miles on the box? It just might be time for a rebuild.

[azasadny]

A gallon of Swepco and new bushings and my tranny shifts like new! I hope that's what your problem turns out to be. Very cheap, easy fix!

[Peter Bull]

Originally posted by raven1700
Also in this same transmission I can't downshift from any gear to 1st, unless speed is below 5mph and reverse is difficult to get into at times. Please help, what could be wrong?

Is that because of grinding (dog)teeth, or just a lot of resistance? Because if it is grinding teeth then the syncro rings and sleeves are worn out.

If it is not grinding teeth, then it is possibly a matter of changing the pieces the other guys have mentioned and adjusting the shift linkage.

/Peter

[livi]

If original box certain internal parts will likely be a bit worn, like first and second syncros. As already stated, the bushings of the lever, rod and coupling together with fresh lube (Swepco is popular) will hopefully make a very noticeable difference though.

Listen to the rookie guys - starting to sound like I actually knew something about vintage 911´s..

[raven1700]

Its a very loud grinding noise and a LOT of resistance getting the car in gear.

[lonewolf]

are you sure clutch is fully disengageing ?

[Jim Sims]

Grinding means synchros are shot; if it's doing that in three gears and has been driven much in that condition then plan on around $1000 or more in parts (three dogteeth, two operating sleeves, 5 synchro rings, 5 sets of brake bands, gasket and seal kit) plus labor. Grinding going into reverse indicate clutch problems, try having it adjusted.

[Peter Bull]

Approach this in three steps:

1.) Ensure that both shift linkage and clutch are properly adjusted
2.) Update the shifter bushings
3.) Repair the transmission

If it does not work properly after step 1 go to step 2 and if it still does not work properly do step 3. While you have the engine and transmission out of the car, also check that the clutch is ok.

It is allways best to weed out the least expencive possibilities first.

/Peter

[MBEngineering]

HI Raven 1700 go get new oil and a selector plate gasket, jack up the car and drain the oil into a clean drain bowl, take off the selector plate from the bottom of the box carefully and check for parts, let the oil drip for some time and then have a look in the box you can see 1st/2nd gear sincro bands,3rd/4th also to asses the damage/wear + what ever is in the oil and on the selector plate, as what to do next.

regards mike

[raven1700]

where is the selector plate and what is the part number for its gasket? Also what is the part number for the shifter bushings? BTW I've driven the car less than 2000 miles in this condition, but no idea how long the PO had it like this. Here is one part of the problem, I bought the car from westside motorsports in Venice, ca. If you do a look up of them on this board, all you will find is negative comments. (Makes me wish I found this site earlier) The car has problems in almost every department, tyranny, fuel delivery, suspension, electrical, body (found rust in the sunroof area). Things that I never bothered to check because the dealer said that the car was fine. The dealer gave no maintenance records, toolkit, receipts, or any thing else about the car. The car has a little under 149K on the whole car. The engine does not have the chain tensioner updates, nor new valve cover gaskets (the dealer said that he was going to have a complete tune-up, including a valve job done). Also he said that he put in a clutch, is there any way to tell whether he did so and if he botched the job?

[LakeCleElum]

With all those headaches, I'd get a API (after purchase inspection) and try to verifty the dealer didn't do things he said he did. I then go after the dealer and/or start in on your list. Sounds like the car was abused........

[MBEngineering]

HI raven 1700 sorry to see you have a few prob's with the car , i would get a inspection as LakeCleElum suggest ASAP, find a guy that knows 911's to do it, then as long as you did not bye it "as seen" go and see if the so called dealer will sort/refund some of the repair work, i would also ring round to get some prices for the work, so you know what the score is price wise to repair the car.
Good luck.

regards mike

[Jeff Alton]

Where are you located?

Cheers

[raven1700]

Manhattan Beach. But I am more than willing to drive over 600 miles in a day

[MBEngineering]

HI raven hear are some photos of a box I have in bits at the moment, I have try-ed to photo the box as you would look at it and also without the cases for you, you should have good points on the dog teeth and the sliders, I will see if I have any worn out sliders kicking about and photo them for you.
[img]
this is a damaged 2nd dog with a tooth missing.
http://forums.pelicanparts.com/uploads9/S70001281167399877.jpg[/img] [img]
inside the box to check the dog teeth and the syncro bands for 3rd/4th.
http://forums.pelicanparts.com/uploads9/S70001291167399902.jpg[/img]

regards mike

[MBEngineering]

HI I have junked the worn-out sliders, the best I can do at the moment is in the photos , the slider propped up against the dogs is worn on the points of the dogs , the top dog has the teeth badly worn, but when you look from the side thay look OK , as you look in to the box thay will look OK , the bottom dog has the teeth missing from a bad shift.



regards mike

[Jay Auskin]

Since reverse is tough, I'd start with a proper clutch cable adjustment.

Then shifter bushings, shifter alignment, then worry about rebuild costs.

[teenerted1]

when checking the bushings on the shift linkage....don't forget to check the SET SCREWS!!! amazing how different it will shift when they are screwed in all the way