RFJ

I am at a loss, my 85 stock smooth shifting except for first gear,it grinds i mean it Grinds so bad you do not even try. T put new oil,half and half redline 75-90 ns and regular and its smoother if that is possible. I can come up to a stop sign and put it in reverse while doing 8-10 mph and there is no grind but not into first. all other gears are perfect ,i believe first and reverse share a syncro ? Would youall please throw out ideas? i am lost.Thanks Ray

Tom. M

intermediate plate is out of adjustment. Reverse should have a lockout so don't know how you got it in there at 8 mph.

JET951

Reverse share the shift sleeve with 1st gear , from model year 1985 , this transmission is completely different from the previous year types and this trans does have its own Borge Warner style synco ring for reverse gear ( loose) .
Syncro ring 928 304 211 05 X 6 in this trans ( 5 for forward gears & 1 for reverse)

RFJ

Tom ,could you please explain intermediate plate being out of adj when all other gears are ok,i do not understand,thank you

Tom. M

Typically when I've worked on the double disk cars (pre 85 trans..with no rev synchro)...if the int plate is out of adjustment it will drag when you have the clutch pedal down and those cars will usually have trouble getting into first and rev. You can get it into second and start from there.

I suspect your first gear synchro is in bad shape compared to the rest..thus your ability to get it into the other gears. Try putting it into second gear at a stop...and then go into first. This might help in the interim.

You can search here on rennlist for double disk adjustment for a tutorial on adj. the intermediate plate.

edit:...I'm not an expert on transmissions but I think the general reason is that the first gear synchro can't take a big differential in rotational speed (eg. engine spinning..and trans not spinning)..but when under motion the differential between first gear at speed..shifting to second (corresponding engine speed drop..and constant speed of the trans) is less. (just a swag)

WallyP

If you want to see how much the clutch drags:
- Securely chock the front wheels and apply the parking brake.
- Jack both rear wheels off the ground, and safely support the car.
- Crank the engine and let it idle.
- Put the transmission in second gear and continue to hold the clutch pedal on the floor.
- Release the parking brake. If the rear wheels immediately start turning, the clutch is dragging. If the wheels turn only after several seconds, then there may be only minimal drag.

GregBBRD

Yes, separate syncro for 1st and reverse.

You keep putting the gearbox into reverse while going forward at 8 to 10mph and a weak 1st gear syncro is going to be the least of your problems. I'd recommend that you stop that activity pretty quickly.

Regardless if the clutch is completely releasing or not, you have a weak/broken 1st gear syncro.

RFJ

ok,thank you all. I did not realize that there were separate syncros on each gear,makes sense now. Greg I keep thinking i am driving one of my other cars that starts first where r is on the porsche,no excuse i know but thats what happens.So my next project on it is transmission service.

Dharn55

It has been 12 years since I sold my last 928 but I has a problem with getting it into first gear with no grinding as the synchro was weak. The trick I used was to put light pressure on the second gear synchro, not putting into second gear but just some pressure. Then it would slide into firs time cutting butter.