Tag
Probationary Member
- 6
- 1
- Sep 15, 2014
-
Johnstown,
Colorado
Hey there, folks!
Definitely a newbie here, but I have tried my best to use the search feature. If you believe you see an article that I missed, please feel free to correct me - I apologize if I missed something! Hopefully this doesn't end up in the boneyard of repetitive threads.
I believe I know the dreaded culprit of my problems, but I would like a second opinion before I jump head-first into some shenanigans!
About my car: 1996 (GS) 420A (N/A), F5MC1, POS project car. This transmission, as I hope you would know does NOT have the 36mm nut to tighten (just horseshoe clips). It looked like many folks had trouble with these nuts...no innuendo intended.
Okay, now that we have that out of the way:
My car will pop out of 5th gear occassionally, when on the highway. It seems to only do this at high speeds (70-85mph), and only after a certain period of time (generally after about 5-10 minutes of maintaining that speed), especially going uphill. I have tested this at lower speeds/high pressure (such as going up a hill at lower speeds), and it will not pop out. Essentially, as long as I am not on the highway, it will not pop out. To me, this is a bit odd, as I would think that this higher torque/pressure on the tranny at lower speeds would make it pop out more often.
Okay, next piece: I was a newbie and put in gear oil (I believe it was 75w90?) after my first rebuild. I made the mistake of going to the parts store and asking for advice, instead of doing my own research. My mistake - I own that. Since then, I have put in ATF4. Although I stopped driving it very shortly after it began to pop out, I believe the damage has already been done, and my guess is that synchros will need to be replaced.
Bullet points:
Alright - knowing this (I hope I didn't overload y'all with info), do you believe that synchros are bad?
My follow-up question to this: why would synchros cause issues with staying in gear? I thought their purpose was to "match" shaft RPMS to ensure for a smooth and efficient shift?
Second question: anything I should try before replacing synchros? I have no qualms about tearing out the tranny...again (this will be the 4th time, so hey, I'm at least getting faster!), but wouldn't mind trying a cheaper/faster alternative first. Cable adjustment, perhaps?
Thank you all for reading this! I hope y'all have a great and safe 4th. 'Murica!
Definitely a newbie here, but I have tried my best to use the search feature. If you believe you see an article that I missed, please feel free to correct me - I apologize if I missed something! Hopefully this doesn't end up in the boneyard of repetitive threads.
I believe I know the dreaded culprit of my problems, but I would like a second opinion before I jump head-first into some shenanigans!
About my car: 1996 (GS) 420A (N/A), F5MC1, POS project car. This transmission, as I hope you would know does NOT have the 36mm nut to tighten (just horseshoe clips). It looked like many folks had trouble with these nuts...no innuendo intended.
Okay, now that we have that out of the way:
My car will pop out of 5th gear occassionally, when on the highway. It seems to only do this at high speeds (70-85mph), and only after a certain period of time (generally after about 5-10 minutes of maintaining that speed), especially going uphill. I have tested this at lower speeds/high pressure (such as going up a hill at lower speeds), and it will not pop out. Essentially, as long as I am not on the highway, it will not pop out. To me, this is a bit odd, as I would think that this higher torque/pressure on the tranny at lower speeds would make it pop out more often.
Okay, next piece: I was a newbie and put in gear oil (I believe it was 75w90?) after my first rebuild. I made the mistake of going to the parts store and asking for advice, instead of doing my own research. My mistake - I own that. Since then, I have put in ATF4. Although I stopped driving it very shortly after it began to pop out, I believe the damage has already been done, and my guess is that synchros will need to be replaced.
Bullet points:
- I have replaced all bearings and seals
- ATF4 flush (I am thinking I will do another flush just to ensure that the fluid has not been contaminated in any way
- new clutch and release (throwout) bearing
- Synchro/gear clearance is within specs (per rebuild manual)
- visual inspection of gears is good - All dogs, teeth, keys, and sleeves look brand new
- synchros are NOT brass
- only about 129k on the engine, and I believe fewer on the tranny
- shift forks/pads/sleeves were not worn/damaged
- cables/linkage do not appear to be damaged, but have also not been adjusted
- has NO problem shifting. Super, super smooth; no grinding, no funky noises. It just pops out occasionally.
Alright - knowing this (I hope I didn't overload y'all with info), do you believe that synchros are bad?
My follow-up question to this: why would synchros cause issues with staying in gear? I thought their purpose was to "match" shaft RPMS to ensure for a smooth and efficient shift?
Second question: anything I should try before replacing synchros? I have no qualms about tearing out the tranny...again (this will be the 4th time, so hey, I'm at least getting faster!), but wouldn't mind trying a cheaper/faster alternative first. Cable adjustment, perhaps?
Thank you all for reading this! I hope y'all have a great and safe 4th. 'Murica!