nursing a bad syncro

[1stGenRocks]

k i know im gonna get a lot of crap for this but....

my 3rd gear syncro is dying on me. i have another trans that im going to rebuild to put in but the question for now is what can i do to make this one work a bit smoother until i can build the other and swap them. im running coastal 75w90 gear oil in it and when its cold it shifts tight but smooth. once it gets warm 3rd gear is crunchy. i can make it go in smooth if i get the rpm's right but its a real pain for daily driving.

how heavy of oil can i put in there to make it act like its cold all the time?

 

[1stGenRocks]

somebody has to have an idea for me to try?

 

[xcelr8n]

Thicker oil might help but probably not at this point, any different oil is just a temporary bandaid solution.
You could shift from 2nd to 4th gear, I have a buddy who drove like that for nearly a YEAR before he swapped his tranny. Shift outta 2nd around 3500-4000rpms and you wont even bog 4th gear down. Ghetto I know but it will work...

 

[1stGenRocks]

yea ive been doing that. its just that since it shifts fine cold it seems like i should be able to do something.

 

[Irrational]

Thicker oil might help but probably not at this point, any different oil is just a temporary bandaid solution.
You could shift from 2nd to 4th gear, I have a buddy who drove like that for nearly a YEAR before he swapped his tranny. Shift outta 2nd around 3500-4000rpms and you wont even bog 4th gear down. Ghetto I know but it will work...

i do that my 3rd is shot

 

[Talesin]

I have the same thing with my Mirage. Learn to double-clutch... when you're going 2->3, just shift to neutral, let the clutch out, blip the throttle (I usually pop it higher than neccessary for less grind), clutch and go into third.

Takes practice, but that's how you used to have to do it on a synchroless transmission. Still works, and you can get pretty quick at it after a while.

 

[Spoolin4Ever]

Well you have a couple options;

BG Synchroshift or similar gear oil (GM Synchromesh, etc..). These tend to shift good, but they don't protect as much. So you woulkd need to change it more often (they are thinner).

Or you could use Redline MT90, it is the GL4 spec gear oil. That's what I am currently using.

You could also do a mix. Like 2/3 MT 90, 1/3 BG Synchro, etc..

Personally I like thicker stuff. I am thinking of doing a mix with 1 Quart of Redline Shockproof, and the rest MT90.

I guess the answer is experiemnt with different gear oils.

But is coastal even GL4 compliant? GL4 is easier on brass synchros then GL5 or other Non GL4 fluids. I thought coastal is not GL4.

 

[djXternal]

wow i only wish it was my 3rd goin bad, my second is the one goin bad on me, few months and ill be shifting 1st to 3rd.... not being able to use second is a pain in stop-go rush hour traffic

 

[92GSXBaltimore]

get used to it, you drive a dsm!! j/p try to match your rpms when shifting into gear, and shift slower to allow the syncro cone to mesh with the drive gear. If you do it slower it will have time to "sync-up" with the speed of the countershaft shaft. This will speed up the wear of the syncros themselves but it will prevent damage to the shift fork, syncronizer hub, and drive gear.
Bottom line: You'll kill your syncros faster by shifting slower, but ultimately prevent more damage to the trans.

 

[92GSXBaltimore]

p.s. when i say shift slower, i dont mean clutch operation, i am refering to the shift linkage operation.
p.s.s. double clutching will also work, but it is a pain in the butt and will prematurely wear down your clutch if done long enough.