transmission problems...synchro questions

[cullenj76]

My transmission has been extraordinarily difficult to go in gear lately. I know it is the synchros, but this morning it would not go into gear at all. I sat there for a while until I finally checked the clutch fluid resevoir(sp) and it was bone dry. Couple of questions. Do I need to bleed the hydraulic system now since it was dry?

How difficult would it be to change synchros when opening the transmission?:eek:

Is there an independent synchro for each gear or is there just one?

Do all the synchros usually go out at the same time, or do they go out one at a time?

Once the synchros are gone or bad, are they that way permanently or is there something I can do to temporarily fix it? Will adding some good gl-4 gear oil like redline help at all?

HELP!!

[redstradic]

You know, I wish I could help but that is all way over my head. I am such a noob. All I can do to help is give you a free BUMP!

[NISTECH]

Have you been using sythetic oil in that trans? If so that is likely your problem. The synthetic fluid has been found more recently to be causing a problem with the syncros braking ability it is making the braking surface to slippery and allowing it to continue spinning as the gears clash cuasing the grind. You determine what syncros you need after you tear the trans down and very closly inspect all the components for wear.

Yes you need tobleed the clutch when the master goes dry, but you need to figure out where the fluid went there has to be a leak somewhere in the system.

[cullenj76]

Have you been using sythetic oil in that trans? If so that is likely your problem. The synthetic fluid has been found more recently to be causing a problem with the syncros braking ability it is making the braking surface to slippery and allowing it to continue spinning as the gears clash cuasing the grind. You determine what syncros you need after you tear the trans down and very closly inspect all the components for wear.

Yes you need tobleed the clutch when the master goes dry, but you need to figure out where the fluid went there has to be a leak somewhere in the system.

Well, I had some synthetic GL-5 gear oil in that I had to use until the redline fluid came when I put my new clutch in.

Update: I bled the clutch, flushed the transmission, and put in some Redline MT-90. :bowdown to the MT-90. Everything is back to normal now, minus the holes in the bellhousing which brings me to my next question. How in the heck did these holes appear in the bell housing? One is the size of a quarter, and the other about double that. Any ideas? Im thinking a bolt coming loose or a finger breaking off from the pressure plate?

Thanks for the info on syncros BTW.

[NISTECH]

Can you get a snap shot of these holes?

[cullenj76]

Can you get a snap shot of these holes?

sure can. I'll take a couple of pics after work tomorrow.

[IvoryJ30t]

it wasnt so much the fact that the fluid was synthetic, its because it was GL-5.

gl5 is way too slippery to use in a syncro transmission, and it is also corrosive to the synchros. only use gl4 fluid.

[cullenj76]

it wasnt so much the fact that the fluid was synthetic, its because it was GL-5.

gl5 is way too slippery to use in a syncro transmission, and it is also corrosive to the synchros. only use gl4 fluid.

Yeah, I know to only use GL4. I was without access to GL4 and just finished a clutch swap, so...

I was trying to ask more if the GL4 MT90 is really worth it compared to some dino10w30 as all the nissan mechanics I've talked to recommend it(dino).

[NISTECH]

trans gear oil is suppose to be 75-90 or 80-90 not 10-30?? what nissan techs are recommending that?

[cullenj76]

trans gear oil is suppose to be 75-90 or 80-90 not 10-30?? what nissan techs are recommending that?

All the techs around here say they use 10w30motor oil not gear oil in the trannys of serviced vehicles.

[IvoryJ30t]

thats very wrong.

worn gear teeth, synchros, bearings...

[NISTECH]

All the techs around here say they use 10w30motor oil not gear oil in the trannys of serviced vehicles.

I have known techs that do stuff like that, but makeing a statment about it is usually followed with the comment "future upsell".

I look at that as being similar to going to the local mall and loosening a few drain plugs on cars in the parking lot. potential buisness. :rolleyes

[IvoryJ30t]

speaking of such, i did the front brakes for someone i know the otherday, and the prior person/shop put the inboard pads in upside down.

i wonder if it was a mistake, or if they intentionally did it so he wouldnt hear the squealer and ruin his rotors.

maybe someone just forgot that the squealer goes on the pads trailing edge.

[NISTECH]

I deal with alot of rookie techs that dont know the difference and assemble them improperly. I dont think it was intentional. I have even caught some long time techs do the same thing due to lack of attention to detail [ the down side to flat rate is quality will likely suffer]