grinding 3 - 4... glass trans problem?

[clint4502]

I've noticed when shifting from 3rd to 4th i get a grind as it moves into 4th. its been doing this for about 100 miles now. 75k on the car with stock clutch and trans. stage 2 mods. no launches, a few hard take offs but i've taken it easy on her otherwise. i've had other problems with the car not wanting to go into gear if i'm moving through the gears quickly above 4k rpms... any similar problems or advice? thanks!

[420sx]

GM Synchromesh should help significantly. Try changing the trans fluid and use a quart of synchromesh with the new fluid.

(but first make sure its ok to use in suby trannies, as I have very limited suby knowledge. Ive used syncromesh in my Hondas and Nissans, as well as friend's domestic vehicles with great success)

[jpalamar]

Syncromesh is good stuff, but if your having the issue with 3-4 for the most part, it could be your syncros. Try double clutching and see if it goes away.

[Honest_Bob]

Start saving chief.

[clint4502]

Originally Posted by jpalamar

Syncromesh is good stuff, but if your having the issue with 3-4 for the most part, it could be your syncros. Try double clutching and see if it goes away.

i thought the same thing... i've tried double clutching and it will still do it unless i'm at rpms lower than 2k. i figured it was probably a syncro issue as well.

[clint4502]

Originally Posted by Honest_Bob

Start saving chief.

haha that's what i was afraid of

[jpalamar]

Also, when was the last time you changed your trans and diff fluids?

[Ender81]

Originally Posted by jpalamar

Also, when was the last time you changed your trans and diff fluids?

This right here was going to be my question.

[Honest_Bob]

Originally Posted by jpalamar

Also, when was the last time you changed your trans and diff fluids?

True!

Don, what gear did yours start having trouble with?

[clint4502]

Originally Posted by jpalamar

Also, when was the last time you changed your trans and diff fluids?

i changed my trans fluid about a year ago... car probably only has around 10k on it since. i was told to use royal purple because it would be better than some others... now i'm wondering if that accelerated my problem. does anyone have more information on the GM Synchromesh or any other fluid i should have used? also, I have not changed the diff fluids.

[Supraru]

You could try Uncle Scotty's cocktail. Usually works pretty great and it shifts really smooth but there are some downsides to it. I guess there's something in there that doesn't agree with certain parts or something like that. It's only a band aid really. I used motul gear 3000 on mine when it started grinding in 4th and it worked great for a while then came back. You're pretty much past the point of fixing it.

I have an 03' for sale that I just rebuilt with the updated parts. 1st gear was replaced by the previous owner and I replaced 3-4 along with the shift sleeve and hub. Didn't have any grinding issues either. I still have to put the hub and sleeve in so if you wanted it while I have it open if you wanted to replace the syncro's I could do that for you pretty cheap since I'll already have it split and one of the shafts apart. Obviously you'd have to buy the new syncros.

[clint4502]

Originally Posted by Supraru

You could try Uncle Scotty's cocktail. Usually works pretty great and it shifts really smooth but there are some downsides to it. I guess there's something in there that doesn't agree with certain parts or something like that. It's only a band aid really. I used motul gear 3000 on mine when it started grinding in 4th and it worked great for a while then came back. You're pretty much past the point of fixing it.

I have an 03' for sale that I just rebuilt with the updated parts. 1st gear was replaced by the previous owner and I replaced 3-4 along with the shift sleeve and hub. Didn't have any grinding issues either. I still have to put the hub and sleeve in so if you wanted it while I have it open if you wanted to replace the syncro's I could do that for you pretty cheap since I'll already have it split and one of the shafts apart. Obviously you'd have to buy the new syncros.

i guess its worth a shot for Uncle Scotty's cocktail. i'll try that first and then if i still have problems i'll get back to you about the '03 trans. thanks man.

any other suggestions before or about the cocktail from anyone?

[Supraru]

Originally Posted by clint4502

i guess its worth a shot for Uncle Scotty's cocktail. i'll try that first and then if i still have problems i'll get back to you about the '03 trans. thanks man.

any other suggestions before or about the cocktail from anyone?

Unfortunatley that's pretty much a last resort to buy some time.

[Honest_Bob]

Yeah, get that Royal Purple junk out of there!

[Ender81]

Mine was a fourth gear grind. It started at around 55K and lasted until 106K. Good trans fluid will do wonders. Never had a need for Uncle Scotty but I guess it can't hurt and yeah Royal Purple blows.

[clint4502]

thanks for the help. i'll be de-purplizing my tranny asap!

[JB'sLGT]

while a whine and grind aren't the same, I had very loud whine with whatever crap was in my trans...I changed the old fluid for Extra S and no more whine

[Supraru]

Originally Posted by JB'sLGT

while a whine and grind aren't the same, I had very loud whine with whatever crap was in my trans...I changed the old fluid for Extra S and no more whine

Yeah just a little different. You can usually tell a huge difference between good and bad fluid.

[clint4502]

Originally Posted by Supraru

Yeah just a little different. You can usually tell a huge difference between good and bad fluid.

haha, yeah i took the car out after the fluid change and questioned my choice because it didn't seem to make the shift smoother... now i completely regret my choice and hope my trans will eat up the cocktail without getting worse.

[Honest_Bob]

Give the new stuff some time to break in.