Transmission Problem. could use the experts opinion or help
03-19-2013, 10:56 PM
#16
Team Owner
When I worked In Utah at Motorsport we replaced 2 shifter forks ,
when compared to a new part it was off by a bit but noticeable,
and the trans was popping out of gear.
We also replaced the shaft bearings as they were worn.
Gregs explanation also makes sense.
I am sure he has way more experience than I do on the 928 transaxles
Another possibility is that the shifter may be out of adjustment
and thus its hitting the bodywork ,
so maybe adjusting the rear shifter coupler connection could be done to see if it makes a change. Before other more expensive things are investigated
when compared to a new part it was off by a bit but noticeable,
and the trans was popping out of gear.
We also replaced the shaft bearings as they were worn.
Gregs explanation also makes sense.
I am sure he has way more experience than I do on the 928 transaxles
Another possibility is that the shifter may be out of adjustment
and thus its hitting the bodywork ,
so maybe adjusting the rear shifter coupler connection could be done to see if it makes a change. Before other more expensive things are investigated
03-19-2013, 11:12 PM
#17
Rennlist Member
Mark, stock shifter?
03-19-2013, 11:14 PM
#18
Former Vendor
03-19-2013, 11:51 PM
#20
Rennlist Member
Albeit not in a 928 xmission I have replaced gears because the box would drop out of gear. As Greg explains the 'dogs' mesh on 2 gears that in this case represent the 2nd gear ratio.
In this instance one normally tries to force the gear to remain engaged which in turn can wear out the shift fork.
Replacement of the 2 gears cures the issue but the tranny has to be dropped and stripped.
Unless as Jim states its a simple cheap thing
In this instance one normally tries to force the gear to remain engaged which in turn can wear out the shift fork.
Replacement of the 2 gears cures the issue but the tranny has to be dropped and stripped.
Unless as Jim states its a simple cheap thing
03-20-2013, 01:32 AM
#21
Former Vendor
When I worked In Utah at Motorsport we replaced 2 shifter forks ,
when compared to a new part it was off by a bit but noticeable,
and the trans was popping out of gear.
We also replaced the shaft bearings as they were worn.
Gregs explanation also makes sense.
I am sure he has way more experience than I do on the 928 transaxles
Another possibility is that the shifter may be out of adjustment
and thus its hitting the bodywork ,
so maybe adjusting the rear shifter coupler connection could be done to see if it makes a change. Before other more expensive things are investigated
when compared to a new part it was off by a bit but noticeable,
and the trans was popping out of gear.
We also replaced the shaft bearings as they were worn.
Gregs explanation also makes sense.
I am sure he has way more experience than I do on the 928 transaxles
Another possibility is that the shifter may be out of adjustment
and thus its hitting the bodywork ,
so maybe adjusting the rear shifter coupler connection could be done to see if it makes a change. Before other more expensive things are investigated
There you go. It is possible.
I try not to speak in "absolutes" when dealing with mechanical things. You hang around long enough and you get to see one of everything.
03-20-2013, 06:03 AM
#23
Instructor
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Hopefully you find an easy fix but I think you'll have to tear the trans apart. I would expect to find a problem in the 2nd gear hub assembly. Either bad needle bearings, the detents or clips/springs that hold them in.
03-20-2013, 12:14 PM
#24
Race Director
I'm also leaning towards a worn transmission issue..... I think this is a "new" used transmission that MK got after he broke the original Holbert trans at Thunderhill a couple years ago..... So it is the later Borg Warner box with LSD.....I think MK runs stock shifter bushings-coupler too, with a "red" short shifter
03-20-2013, 02:27 PM
#26
Former Vendor
03-20-2013, 02:52 PM
#27
Rennlist Member
Thread Starter
its something in the trannie, which is a stock 87 S4 2.2.
some kind of keeper or spring load that keeps the gear in gear, unless acted upon by the shift mech.
03-20-2013, 02:54 PM
#28
Rennlist Member
Thread Starter
When I worked In Utah at Motorsport we replaced 2 shifter forks ,
when compared to a new part it was off by a bit but noticeable,
and the trans was popping out of gear.
We also replaced the shaft bearings as they were worn.
Gregs explanation also makes sense.
I am sure he has way more experience than I do on the 928 transaxles
Another possibility is that the shifter may be out of adjustment
and thus its hitting the bodywork ,
so maybe adjusting the rear shifter coupler connection could be done to see if it makes a change. Before other more expensive things are investigated
when compared to a new part it was off by a bit but noticeable,
and the trans was popping out of gear.
We also replaced the shaft bearings as they were worn.
Gregs explanation also makes sense.
I am sure he has way more experience than I do on the 928 transaxles
Another possibility is that the shifter may be out of adjustment
and thus its hitting the bodywork ,
so maybe adjusting the rear shifter coupler connection could be done to see if it makes a change. Before other more expensive things are investigated
03-20-2013, 03:05 PM
#29
Rennlist Member
Thread Starter
The syncro only slow or speeds the gear up. It doesn't actually do anything to keep the slider engaged with the engaging teeth on the gear. The "teeth" have a "negative angle" on both the engaging sleeve and the engaging teeth on the gear. When the teeth are fully engaged (and in good condition) these two "negative angles" are touching each other, which effectively "locks" the two pieces together.
If the "teeth" are not able to fully engage (something limiting the travel of the shifter, bent shifting fork, etc.) the transmission will pop out of gear. Wear on the teeth can also this to happen. Excessive endplay or a bearing issue will also allow enough movement to allow them to pop out of gear.
If the "teeth" are not able to fully engage (something limiting the travel of the shifter, bent shifting fork, etc.) the transmission will pop out of gear. Wear on the teeth can also this to happen. Excessive endplay or a bearing issue will also allow enough movement to allow them to pop out of gear.
possible. hmmmm
Albeit not in a 928 xmission I have replaced gears because the box would drop out of gear. As Greg explains the 'dogs' mesh on 2 gears that in this case represent the 2nd gear ratio.
In this instance one normally tries to force the gear to remain engaged which in turn can wear out the shift fork.
Replacement of the 2 gears cures the issue but the tranny has to be dropped and stripped.
Unless as Jim states its a simple cheap thing
In this instance one normally tries to force the gear to remain engaged which in turn can wear out the shift fork.
Replacement of the 2 gears cures the issue but the tranny has to be dropped and stripped.
Unless as Jim states its a simple cheap thing
03-20-2013, 04:28 PM
#30
Former Vendor
I was cleaning the parts for a 1989 five speed yesterday and pondering the future of these transmissions [and all of its direct relatives that use the same parts (1987 to 1995.)]
Since the 5th gear input bearing, the bearings that the layshaft turns on, and the shifting lock-out spring are all NLA, rebuilding one of these things is going to quickly turn out to be a real parts problem.
About the only "standard" wear repalcement parts that we can now get is the syncros and the gasket set....and the syncros are now $250 each.
Since the 5th gear input bearing, the bearings that the layshaft turns on, and the shifting lock-out spring are all NLA, rebuilding one of these things is going to quickly turn out to be a real parts problem.
About the only "standard" wear repalcement parts that we can now get is the syncros and the gasket set....and the syncros are now $250 each.