901 tail shift problems, 901 shifting Options

[GP550]

Hi one and all.
im writing from melbourne australia, i have just imported a Beck 550 spyder from San Fran its running a 13B standard port rotary 180HP / 200Ft-lbs and a 901 tail shift.. The engine runs awesome, its the trans thats the problem..

here is simple list of the probelms..
a) 1st and reverse grinds on engagement when totally stopped.. i have adjusted the clutch to work at 10mm pedal movement..but still it grinds.. more when warm. Ive tried engaging 2nd and 3rd before going for 1st / reverse.. but still the same..

b)I can only get second when moving.. I have to use 1st to get off line, then second will engage.. Other wise second is like its not there. grinds or doesnt go in.

c)The shift pattern is the hunt grind and find.. sloppy to put it mildly.. And yes I have replaced all bushings .. My cup bushing is now bolted through, firewall bushing is new, and rose joints replaced all angle joints ( thanks to pelican parts).. Motor and tranny mounts are new. I even looked at a rennshift.. But cant install due to physical install issues, ( geometry)..

d) 4 th doesn't engage at all, and if it does by shear miracle it grinds and holds for about 5 seconds then pops out under the smallest load

e) 3rd and 5th are great, I can get them every time... as long as Im moving


I have had 2 specialist 356 mechanics look at it, with pivot point and geometry corrected , but I still have a gearbox thats sloppy, grinds and sometimes just doesnt want to engauge gears..

What I have been able to suss out,
1. The shift coupler at trans may be bent.. (
I was told about a cable shift mechanism, any links toa post about this would be great.

2. the shifting fork / s may be damaged - statement was that there may have been gear hammering ??? what ever that means

3. 4th dog gear is stuffed

4. the clutch may need replacement

I have a limited budget $2000 to fix... Im not a mechanics rear end but I love driving it

can any one shed some light on where I am with this box and if my assumptions are correct, and what needs to be done..


Or if any one knows of a 901 gear box specialist in Melbourne, please advise..

any help would be really appreciated, as right now i am cursing the box, starting to hate the car, and the whole experience is just not cool..

thanks
gp

[Bleyseng]

The shift forks could be misadjusted so try that using the Porsche manual to guide you.
or 1st gear dog teeth/slider are so hammered along with second gear that you need to replace those parts along with new syncro's. I would pull the gear stack and inspect those parts and see what going on. Check the reverse gear too for excessive wear on its teeth as if 1st is shot then reverse is a mess too.

[pcar916]

I've driven two Beck 550's and enjoyed the heck out of them them but the shifting was vague in both and both were cable-shifted. Welcome to tail-shifters.
First thoughts:

Cable-shifters are a good option but if you are going to do that anyway, I'd try to find a side-shift 914 transaxle already built. Then you'd have a spare trans to get parts from.

Regardless of whatever else is happening, since 4th gear is gone you have to take it apart, so have some fun.

Everything outside the transaxle has to be right first, including bushings and all slop removed from moving parts and shifter adjustments. Once they're right then it's a matter of internal inspection. Here's what I'd do in your position.

1. Buy Dr. Evil's transmission Rebuild video. PM Cupomeat (on this forum) and ask how to get it now that it's in post-production. It's really good.

Cupomeat = http://www.914world.com/bbs2/index.php?showuser=8376

Until then take a look at this thread.

http://www.914world.com/bbs2/index.php?showtopic=18128

Assuming you don't have ring-and-pinion issues, make sure you remember how many gaskets were underneath the intermediate-plate, and what the total thickness was. All gaskets are not the same thickness.

You'll have to inspect for rounded (bad) dog-teeth, broken synchronizer bits and worn spider-feet and/or shift-sleeves. The bearings and their races might be good but have to be inspected for pitting.

There are special tools you must have to remove/install dog-tooth rings and an alignment jig to install the shifter rods, as well as a good dial caliper or micrometer. Neither of the above include ring-and-pinion setup so don't open that part of you case unless you have carrier bearing issues (noise from them). That's a whole different set of tools and you have to have access to lot's of shims and spacers specific to 901/914/915/930. You can use late 915 spacers and shims but the cutout for the reluctor-cutout has to be set so you can still get gear-puller jaws under them. Note, Harbor-Freight pullers don't have thin enough jaws to be useful. I made my own and case-hardened them. Grinding down cheap jaws makes 'em break, and they tear up your expensive spacers and new bearings. Ask me how I know...

Good luck!!! (IMG:style_emoticons/default/beerchug.gif)

[Rav914]

First and foremost get the aforementioned video. It's a great tool that teaches you the innerworkings of a transmission. Invaluable.

Second, I recommend you keep the tailshifter. Once you get the internals sorted you'll be fine. Changing to the side shift invloves more work and $. You'd be back at square one. I have a low-mile, solid side-shifter on my '74 and it works great but so does the tail-shifter on my '70. The 'vagueness' adds to the charm of a classic car.

[1968Cayman]

I'll trade you a live kangaroo for the 901 I have in the garage.

Honestly, I'd sell you the box cheap but the shipping costs would probably be a tad high & I never drove the car it came out of so you could find yourself in the same situation (though I was given assurances about its condition when pulled). However, if worse comes to worse and you start looking for another box to stuff in there, send me a note; I don't think these things are worth more than a couple hundred bucks.

[Dr Evil]

There is no provision for synchronization of reverse. If reverse grinds it is telling you that your clutch is not fully disengaging. The grind is due to the input shaft still being spun while you are trying to put the slider into reverse. This is the first thing to fix and all else will likely go away. Check my 31 pages of notes in my sig, and I still have the video available should you wish to go that route.

[GP550]

the clutch thing was the issue.. I just found that the hydraulic clutch ( Neal ) is loosing past the seals.. but only once the the clutch had been operated 20 or so times ( warm up the fluid and it leaks).. what a bastard

Am having the seals replaced this week.. will advise once completed..

in any case thanks Dr Evil.. impressive is all I can say.. even at long range