930 Turbo NO reverse gear - possiable explanations (internal to transmission)

strictly · 02-11-2017, 01:45 AM

I have lost reverse gear on my 930 (1987 4 speed manual).

I have disconnected the gear linkage at the coupling, and can confirm it is INSIDE the transmission (not a clutch or gear linkage issue). I can select all 4 gears manually using either my hand on the coupling OR if I connect the gear linkage, but NO reverse.

I have checked if the shift rod was loose on the 4 bolt cover under the transmission (it was not), and now conclude its an internal transmission problem. I have pulled the trans and engine and going to look at it over the weekend.

What are the likely problems and first steps towards repair (besides giving it to someone else)? If it something I can fix I WILL post photos, as we all like pic heavy posts!!

Flat6pac · 02-11-2017, 03:30 AM

Seen it before
There is a pin that has dropped off.
Reverse is located just inside the cover. Remove cover
Trying to engage, you lol see what's not moving, a rocker shaft that engages reverse.
Pin has moved off location
Bruce

Joe Bob · Joe Bob's Garage

Yup, happened to me once. PITA.

john walker's workshop · 02-11-2017, 04:17 AM

Likely the fork that engages the reverse gear is bent. It's mild steel.

strictly · 02-11-2017, 08:17 AM

Thanks guys very interesting, so not a complete drama then =)

Well that's a start. I'll take off the nosecone, investigate and will post some pics. I'll save any further questions until then, at least for the moment it sounds simple =)

proffighter · proffighter's Garage

There is an bulletin concerning improved fork... Be sure to buy this one

strictly · 02-13-2017, 09:11 AM

Quote:

Originally Posted by proffighter

There is an bulletin concerning improved fork... Be sure to buy this one

great tip, i;ll try and find it.

strictly · 02-13-2017, 09:42 AM

ok so i took the nose cone off and found this...

The fork is broken. I'll look into ordering one (the improved version). In terms of putting things back together - Do i need to try and mesh the gear in the nose cone? with the other two gears in the box, or does it not really matter. I have marked the gears against the box with red pen, just in case everything needs to go in exactly in the same place.

I found that in order to get it into reverse (i.e acttivate the reverse shift rod)- I have to put a vice grip on the coupling, because the "gate" is inside the box with quite a lot of spring tension. Is this normal for turbos? I have taken the spring and plunger out and given it a polish, so it moves a little bit freer. I also have a 3.2 (915) trans lying around, and it is much easier to engage reverse by hand using just the coupling.

Here are the photos.

proffighter · proffighter's Garage

Here is a pic to compare them, 1mm thicker. If bulletin is needed, let me know, got to search then

strictly · 02-14-2017, 10:19 AM

Hi Roland, thanks bud. I found the bulletin. In fact I found a PDF with all of the bulletins - do you need copy? its 560 odd pages for 74 - 89 cars! Thanks for your help =)

Anything you can think of to say when I put it back together? like does it matter if the gears don't align in exactly the same place as before. I found the "gate" which keeps you from slipping into reverse by accident, needs a vice grip on the coupling to enagage. I have a 3.2 box also to hand from my 3.5, and I can engage all gears including reverse with just the coupling. Is it normal for turbos to be harder to engage/activate the revers "gate" by hand?

Here is the bulletin you talked about - for the benefit of anyone else that needs this thread in future :

KTL · 11:11 AM

No need to worry about the gears staying in the same tooth position. Since the gears are different diameters (and thus have different tooth counts) the teeth are not always engaging the same tooth every rotation.

edit: forgot to include a good video showing 930 trans disassembly and reassembly. No affiliation with Speed Academy and no endorsement from me on their approach. Just happened to stumble across this video awhile back and thought it was a decent one to watch.

https://youtu.be/rjUuIUrcZBg

strictly · 02-15-2017, 03:13 AM

Quote:

Originally Posted by KTL

No need to worry about the gears staying in the same tooth position. Since the gears are different diameters (and thus have different tooth counts) the teeth are not always engaging the same tooth every rotation.

edit: forgot to include a good video showing 930 trans disassembly and reassembly. No affiliation with Speed Academy and no endorsement from me on their approach. Just happened to stumble across this video awhile back and thought it was a decent one to watch.

https://youtu.be/rjUuIUrcZBg

Thanks for the tip - and i'll watch the video tonight (or this week, I have a date tonight, and its not one of my cars lol), its my first time doing anything inside the trans, so its i'm enjoying learning more about its guts