vcompetello

Hi folks,

My transmission is currently on the floor along with my entire rear suspension (Sorry no pictures). It's a 1980 euro so obviously I've been having some synchro problems in 1st and 2nd. So now I have two questions. First, how long are these new synchros going to last? When I bought the car it was already grinding and the odometer is busted so I don't know how long it took for the synchros to go. Second, is there anything I can do to make these synchros last a little longer. From what I hear the early 5-speed's synchros don't last long at all. How can I make sure I don't have to do this all over again this time next year?? Thanks a lot

Vinnie

BC

I am also listening. I bought a second 78 trans to rebuild.

JET951

hi guys,

well we have rebuilt plenty of early and late 928 gearboxes. we have never had one come back in for any problems. the synchros will last as long as you let them. if you are a sloppy driver then obviously they will wear out quicker. some of these rebuilt boxes have over 100 000kms, as i said no problems yet. while you are in there check all the synchros and dog teeth and make sure you check the selector rings. if the selector rings are worn only slightly they will cause problems. also check the 1st reverse brass selector for wear.

oh and we assemble everything with bearing grease. lots of it. they are great boxes to pull apart.
hope this helps. any more questions just ask

Sean Buchanan
Buchanan Automotive

tammons

If you have 1st and 2nd gear syncro problems, IMO someone probably kept on driving it with a dying clutch.

From what i remember the early ones are made of brass. I you abuse them they will fail faster. The later ones are made of a denser metal. I want to say iron, but that may not be right.

tammons

Oh, how long will they last.

If you drive normally years and years. I have bought 20 yo cars with the original drive trains that were fine.

If you race, turbo, SC it might be a good idea to upgrade the syncros.

gruffalo

Make sure you adjust the clutch intermediate plate, to keep the clutch from dragging. This kills synchros.

I think devek have instructions on their site.


mm

hacker-pschorr

Too many early 5-speed 928's were driven for long periods of time with the clutch adjusted poorly. My 81 had an intermediate plate that was sticking, would not float between gear changes. Due to the complex install and expensive parts, most owners did not spend the money over the years to keep a good clutch in the car.

BC

Do you have a picture of the selector rings?

jyoon

there are two selector rings shown in this photo, one toward the top and one toward the bottom.. this is from an 84 euro.

BC

I bought some used ones from ebay, if I think I know what you mean. The ones with the black band in them? The ones I bought were a bit worn - are the teeth supposed to b e sharp and straight I assume?

jyoon

i think the shift rings wear out since they are rubbing against the synchros when you shift gears. when i took the top shaft (in photo) to a tranny guy to get the gears pressed off, he said the shift rings were shiny and smooth. he said he roughed them up a little with some sandpaper. if you compare new synchros to old ones, you will see they have a rough texture to them and are not smooth and shiny like worn ones. i think it may be similar with the shift ring but not certain.

vcompetello

Ok I have another question. How much play is there supposed to be between the gear selector collar and the hub it sits on. My selector collars seem like they have a good deal of play but they still spin the hub. I mean, I can't make them slip or jam. Also, they grab the synchros that are still good pretty tight. My father (a mechanic for 30 years) seems to think they shouldn't be a problem but there's more play than I'm comfortable with. Any opinions??

Lance J

i just rebuilt my own box last year. and have another one being put in the car. install my box i rebuilt my self. the i decided to buy another one and have it done by a tranny guy. so i gonna ride the one my tranny guy rebuilt for me and see how long that last. then i'm sending my other box off to get beefed up for my turbo set