slight grind... clutch or synchros?

[S13squirrel]

Okay well this will prove my newbie-ness... What does it fee like when your clutch is wearing out? I have noticed recently that when I shift quickly into 3rd while coming out of high RPM's in 2nd, I get a bit of a "graunch" sound. It goes into gear, but definitely not smoothly. If I take longer to shift (foot on clutch longer), the noise does not occur. Same as if I shift out of 2nd at normal RPM's (3k), no matter how hard I shift. It really only does it in 3rd, as far as I can tell, but this may be because 2nd is the only gear I really run to redline. Is this my clutch fading or my synchros in 3rd?

[007jpang]

change transmission fluid ... to that thick redline oil, royal purple... and see that happens... next

[S13squirrel]

I already changed the fluid in december... might I just need to top it off again? We filled it right up to the fill hole, I stuck my finger in and could touch the top of the new oil.

[kandyflip445]

If you had just bought the car and the maintenance wasn't good then the fluid change may have loosened up some material causing the fluid to be contaminated prematurely. Just change it and see what happens. Make sure you clean off the magnet too.

[S13squirrel]

actually now that you mention it, the magnet was absolutely covered in metal shavings when we changed the fluid in december. We cleaned it off, of course, before putting it back in, but it may have been an indicator of how much mayhem there is inside that tranny.

[Nameless RB26]

If you're clutch is going out, you'd know it. You wouldn't just have a 2nd-3rd problem.

I think 'kandyflip' in on track with the problem.. but I don't believe it's being caused by resurrected material contamination.

My theory is the opposite. Your older oil had a concentration of transmission poop (shavings, gunk, etc) that was giving the oil a thickening property.. which would make for an operable and seemingly 'ok' shifting gearbox.

When you put clean oil in, you not only drain out the older contaminants, you add detergents that dissolve any of the leftovers. So, viscosity has now changed and the concentration of suspended contaminants is slim to none. The oil properties are much different.. especially if the older oil had been thoroughly used. Your shifting will be more crisp now.. and the sugarcoating properties of your older oil are gone.. so you're going to grind a bit when the oil is cold.

Which moves me to my recommendation of an additive, or a different oil. :)

Older transmissions need different oil as they are more temperamental due to synchro/gear wear. So.. you probably need something thicker than what you're using now. If you're using a thick oil already.. then I'd try switching to a more 'exotic' oil of the same weight.

Additives would likely be ok too.. but I'd be picky about which one to use. Mixing oils doesn't always work out right. (ie emulsification: like blended water and oil).. you get the idea. Most of the reputable brands are ok though.

I hope that helps. :)

btw, a lot of my basis is from personal experience and expirimentation over the years. I'm not an authoritative consultant in regards to this subject, but I've done my share of research. teeheee. :blah:

[locodrftr]

try to bleed your clutch, and bleed it real good be surprise how much air is in system, bust clutch upgrade was getting a braided clutch line stiffer pedal and no grinding or hard to shift into gears
just my 2 cents. may help

[90RS13]

sure sounds like a syncro thing to me. You could rebuild. Or, you could try using some syncro-mesh. It works well on some cars. My friend has an MR2 and his was bad. Hw couldn't down shift into 2nd at all, unless at almost a complete stop. He used syncro-mesh and now it shifts smoothly all the time.

[nissan_driver24]

If you're clutch is going out, you'd know it. You wouldn't just have a 2nd-3rd problem.

I think 'kandyflip' in on track with the problem.. but I don't believe it's being caused by resurrected material contamination.

My theory is the opposite. Your older oil had a concentration of transmission poop (shavings, gunk, etc) that was giving the oil a thickening property.. which would make for an operable and seemingly 'ok' shifting gearbox.

When you put clean oil in, you not only drain out the older contaminants, you add detergents that dissolve any of the leftovers. So, viscosity has now changed and the concentration of suspended contaminants is slim to none. The oil properties are much different.. especially if the older oil had been thoroughly used. Your shifting will be more crisp now.. and the sugarcoating properties of your older oil are gone.. so you're going to grind a bit when the oil is cold.

Which moves me to my recommendation of an additive, or a different oil. :)

Older transmissions need different oil as they are more temperamental due to synchro/gear wear. So.. you probably need something thicker than what you're using now. If you're using a thick oil already.. then I'd try switching to a more 'exotic' oil of the same weight.

Additives would likely be ok too.. but I'd be picky about which one to use. Mixing oils doesn't always work out right. (ie emulsification: like blended water and oil).. you get the idea. Most of the reputable brands are ok though.

I hope that helps. :)

btw, a lot of my basis is from personal experience and expirimentation over the years. I'm not an authoritative consultant in regards to this subject, but I've done my share of research. teeheee. :blah:


this goes with automatic transmission too... u never want to change the fuilds in an automatic tranny if it hasn't been changed for years and years.....

this sounds like a sychro problem... if u want it to go away... get a new tranny, rebuilt tranny, or rebuild the thing.....

[kandyflip445]

WTF? Never change the fluid? If you don't then it will shit out either way. Unless it's already completely fucked, changing the fluid will help. The fluid is there to suspend the worn material in the fluid and not let it deposit on the parts inside. When you follow recommended change intervals it keeps the contaminates from depositing on the inside of the tranny. (Sludge) It is also used to cool moving parts in the transmission. If you use too thick of a fluid it will hinder the ability to cool and at lower temperatures it will make it harder to shift until it reaches the proper viscosity. Just change the fluid in the tranny and check the condition of the fluid when it comes out. Make sure it's not really thin or has metal shavings. It should have less shavings in your case because you have changed it recently and if you keep the maintenance up on it it should be fine.

[S14DB]

this goes with automatic transmission too... u never want to change the fuilds in an automatic tranny if it hasn't been changed for years and years.....
Yeah, I had this problem. The 3rd gear went bye, bye. But it had problems to begin with. But I've had cars that had no problems and I changed the fluid and then they shifted harder.

[ultraDorksGarage]

id like to add if ur clutch is balloned it will accentuate bad synchros.

second is gear oil additive is a good idea, if not run an oil specific to manual trannys, yes they are slightly diff, same viscosities, but too slippery oil makes synchros slip too much.

third, if your little bushing on the bottom of the shifter wears out, finding gears in a hurry is slightly inaccurate and grind prone. but when the bushing wears it will be accompanied with your shifter feeling really sloppy.

[kandyflip445]

I've never heard the term "balloned". What does that mean?

[ultraDorksGarage]

I've never heard the term "balloned". What does that mean?

excuse my typing ballooned. when the clutch disc begins to delaminate it becomse wavy and ballooned. when u depress clutch the clutch disc is so thick it still spins(although theres no pressure so it wont move your car) and ull feel like u cant press ur clutch in deep enough.

this is common on multi disc clutches on trucks. getting into lower gears, or any gear while rear axle is on low split is teeth grindingly painful.

basically thats why trucks have another plate behind the throwout bearing called a clutch brake, this allows pressure plate disc(not clutch disc) to have a friction brake to stop rotation....

but i digress, u were prolly just laughing at my bad typing skills, lol

/em slaps own face....

edit: but again my moneys on fluid or the little cup bushing in the shifter...

[kandyflip445]

Actually I didn't know what you meant and didn't know it was spelled wrong. lol

[nissan_driver24]

WTF? Never change the fluid? If you don't then it will shit out either way. Unless it's already completely fucked, changing the fluid will help. The fluid is there to suspend the worn material in the fluid and not let it deposit on the parts inside. When you follow recommended change intervals it keeps the contaminates from depositing on the inside of the tranny. (Sludge) It is also used to cool moving parts in the transmission. If you use too thick of a fluid it will hinder the ability to cool and at lower temperatures it will make it harder to shift until it reaches the proper viscosity. Just change the fluid in the tranny and check the condition of the fluid when it comes out. Make sure it's not really thin or has metal shavings. It should have less shavings in your case because you have changed it recently and if you keep the maintenance up on it it should be fine.


what i ment was not to change auto tranny fuild if is hasn't been changed in a very long period of time.... NOT when it is changed at the manufactured recommend intervals.... sorry for the miss understanding....

and once the transmission is already grinding... changing the oil often won't do crap for it... it's not like it's magically stop grinding cause the transmission is now being well kept.... only thing to do is to fix the actural problem.... i hate how some people think there's always an easy way to fix something...


the shop i work at there's this guy that just bought a 96 volvo automaic turbo with 224k miles on it drove perfectly fine and the previous owner never changed the tranny fuild... so the new owner decided to get a transaxle flush.... the transaxle totally failed was slipping like crazy, no reverse at all ,and basically was un drivable.... just from a transaxle flush.... cost him over $2000 to fix a $2000 car...

[ultraDorksGarage]

dont tell people to not change manual gear fluid><

yes fluid can help the grinding on synchros. if u run pure gear fluid on a synchro mesh gear box you can burn your synchros during heavy use. friction modifiers will reduce the slip, and make the synchros sync rather than just slip.

i dont care if u think that the "if it aint broke dont fix" it idea is holy. yes, perhaps ull find problems u never noticed before, but if i threw sawdust in your tranny and it runs, does that make it right???? no fix it and maintain it.

having done many rebuilds on manuals and autos, ill tell u this, not changing fluid on a manual tranny might work sorta well in terms of observed operation. but really thats just ignoring the problem.

id rather change fluid in an auto, realize my clutch bands needed changing, then running it, breaking it on the road, towing it, fixing the bands, the burnt TConverter, the pump, and getting the caramel out of the valvework yadda yadda yadda.

edit: sorry to be so abrassive, but until recently i took care of a fleet of tractors/forklifts/trucks/farm equipment by myself. when my budget for maintanence got cut, i spent way more time fixing major crap than maintaning, which is alot easier than larger problems on heavy equips

[nissan_driver24]

dont tell people to not change manual gear fluid><




if u are responding to my quote... where did i state that... i did before but corrected myself...

[ultraDorksGarage]

the post had more to do with the fact that type of oil in the tranny has alot to do with synchro mesh. as nameless stated, dirty oil has less lubricity but a higher viscosity. new oil meant for diffs and not trannys have medium visc. and high lubricity.

second, in an overly generalized statement if u read on, it talks about an auto tranny. maintanence on an auto tranny will improve clutch band life. sure if previous owner put in "gunk tranny goo" and u take it out it wont run anymore. but do u really wanna chance running on "gunk"?

[ace240sx]

I will rebuild your tranny for $150, get the parts from courtesy-nissan, if you have a SR you will need to buy 2 sets of 1st&2nd synchro and baulk rings. If you have a KA then just buy the corresponding parts.

I have rebuilt 2 SR trannies now and have the process down, the 3rd&4th synchro will need to be machined down on one face.

email [email protected] if you want more info

[kandyflip445]

I should have made it clear that I'm like ultra. Ignoring maintenance so your tranny won't crap out pisses me off and I think that you should just rebuild it if shit happens. Rebuilding is easy if you have the FSM. I dunno why you would need 2 1st->2nd syncro assemblies. Sounds like he's just trying to get some parts. The blocking rings, or baulking rings as said in the FSM, come with the syncronizer assemblies. Also I don't know why you would have to machine anything? Care to elaborate?

[ultraDorksGarage]

I should have made it clear that I'm like ultra. Ignoring maintenance so your tranny won't crap out pisses me off and I think that you should just rebuild it if shit happens. Rebuilding is easy if you have the FSM. I dunno why you would need 2 1st->2nd syncro assemblies. Sounds like he's just trying to get some parts. The blocking rings, or baulking rings as said in the FSM, come with the syncronizer assemblies. Also I don't know why you would have to machine anything? Care to elaborate?

machining is to get rid of runout and such. synchro rings normally are seperate from the baulks. however while ur in there id do every synchro baulk except for reverse.

ace, ur a nice guy, i woulda charged twice as much>< then again im an ass, lol

[kandyflip445]

I haven't had to machine any? What are you guys running into that I'm not. You just have to make sure that the grooves on each blocking ring are sharp. If they are they're fine.

[S14DB]

So, Who has a Tranny rebuild guide? Tips and tricks, parts list....

[ace240sx]

Well if you knew anything abnout the SR and KA tranny then your question about 2 synchros and machining would be answered. First the 3rd&4th SR synchro is much larger than the KA's. The 1st&2nd sr is the same size as its 3rd&4th, and the same size as the KA's 1st&2nd. So 2 KA 1st&2nd work in the SR.

Also the SR will need a 1st&2nd synchro to be machined down 2/100 of a inch on one face, this makes it the same size as a SR 3rd&4th, so the E clip will fit in its proper slot on the main shaft. The baulk rings can be used for both synchros without no changes.

If you disagree order one from japan...

Kandyflip you are a moron, the baulk rings are seperate from the synchro assembly, you obvisouly have no clue what you are talking about, fsm is a good guide but you also need good bearing pullers, drifts, and a good bearing press. Not to mention all special tools you need made by a machine shop. Add all that up and tel me you can do it yourself with just a fsm.



Go here to my post for more info and pics of the differences. http://forums.freshalloy.com/ubbthreads/showflat.php?Cat=&Board=UBB9&Number=67944154&Forum=All_Forums&Words=synchro&Match=Entire%20Phrase&Searchpage=0&Limit=25&Old=allposts&Main=67943970&Search=true#Post67944154

[kandyflip445]

So I'm a moron because I use KA parts for KA transmissions? I've never worked on a SR transmission and didn't know the difference. Hence the questions, asshat.

EDIT: Oh and when I ordered my syncro assembly it came with the blocking rings but I didn't get it directly from Nissan. :mephfawk:

[kandyflip445]

On a side note. You said on your tranny your 1st>2nd syncro was stripped. What did you mean by that?

[ace240sx]

Stripped as in the triangular peaks of the synchronizer,and baulk ring, were rounded off from grinding the baulk ring against the synchro, so they looked like half circles not triangular. This will make the synchro not be able to freely move between the corresponding gears without heavy grinding.

Kandyflip you should learn how to read people's posts, and understand what they are saying. I specifically said that if you have a SR tranny then 2 of the same synchros would need to be purchased, and one of them machined on one face. THAT WOULD BE THE DIFFERENCE

For those who do not know how the synchro works look below at this picture. You can see the shift forks "wrapped around the synchro" and the baulk rings on either side, they are gold in color. Well when in gear the synchro will be either far left or far right in depending on what gears (1st,2nd or 3rd,4th) the 3rd and wth synchro is the furthest right in the picture, and then the 1st&2nd is left of it. So when you switch gears the synchro will be pushed along the assembly and "catch" onthe baulk ring,then continue to move onto the next gear that you are shifting into. Problems occur when the synchro and baulk rings are worn out.http://memimage.cardomain.net/member_images/7/web/811000-811999/811123_2_full.jpg

[kandyflip445]

I apologize for not reading correctly. But it was still confusing what you said as I didn't know that you couldn't order the proper part for the proper transmission.

On transmission mechanics that's not how a syncro works. If you have one of your blocking rings left look on the inside of the ring. There are groves on the inside that catch on the speed gears cone and bring the speed gear up to speed allowing the syncronizer sleeve to slide over the blocking ring and and the speed gear in effect locking the speed gear to the syncronizer hub which is splined to the output shaft. When the tranny is grinding it is the syncronizer sleeve (the thing the shift fork is holding) that is hitting the speed gear because the blocking ring is worn. Usually it's the grooves on the inside that are worn because when the sleeve slides over the blocking ring and the speed gear they're already going the same speed because the inserts push the blocking ring into the speed gear before the sleeve makes contact. ;)

[ace240sx]

I apologize for not reading correctly. But it was still confusing what you said as I didn't know that you couldn't order the proper part for the proper transmission.

On transmission mechanics that's not how a syncro works. If you have one of your blocking rings left look on the inside of the ring. There are groves on the inside that catch on the speed gears cone and bring the speed gear up to speed allowing the syncronizer sleeve to slide over the blocking ring and and the speed gear in effect locking the speed gear to the syncronizer hub which is splined to the output shaft. When the tranny is grinding it is the syncronizer sleeve (the thing the shift fork is holding) that is hitting the speed gear because the blocking ring is worn. Usually it's the grooves on the inside that are worn because when the sleeve slides over the blocking ring and the speed gear they're already going the same speed because the inserts push the blocking ring into the speed gear before the sleeve makes contact. ;)

You just posted what I said and tried to go into more detail? but you are wrong.

The baulk rings attach to the speed gears at 3 points, and there is about 9mm of freeplay for the baulk ring to move around while it catches the synchro. Now the synchro catches the baulk rings then moves onto the speed gear.

Also grinding occurs when the synchro hits the baulk rings and does not catch and keeps spinning, from what you are saying the baulk ring has engaged the synchro, and the synchro is grinding the speed gear??? that makes no sence because once the baulk ring and synchro are engaged they are at the same speed, and then the synchro can slide onto the speed gear. If this was happenining then the baulk ring would either break at the 3 points where it connects, or be filed down into nothing. Also the baulking ring has grooves on one side, not both lol :ugh:

why try?

[S14DB]

Quit fighting and tell me what parts I need to rebuild my tranny.

[ace240sx]

Here is a picture of how the baulk ring connects to the inner synchro gear, you obvisouly do not know how this works from what you have said above. Once the synchro has moved onto the baulk ring the gear is 1/2 engaged untill that freeplay is used up and then the synchro continues to move onto speed gear attached to the main gear. Grinding occurs when the synchro skips across the baulk rings teeth.
http://memimage.cardomain.net/member_images/7/web/811000-811999/811123_5_full.jpg

Here is a pic of my worn out sunchro and baulk ring from them grinding against each other, if you look closely the triangular peaks of the baulk ring and synchro are rounded off.
http://memimage.cardomain.net/member_images/7/web/811000-811999/811123_6_full.jpg

Now people for the sr20det tranny the machining is needed as follows: look at the first pic and see the gear that is surrounded by the gold baulk rings. This needs to be machined on one face only. Now it will depend on your tranny because it seems that each tranny has different spacers due to tolerances not being exact.


Look at this picture, see the face with the 4 slits in it, well that needs to be machined down so it is smooth and has no more slits on it. This is done for the SR tranny so you can replace the 3rd&4th synchro.
http://memimage.cardomain.net/member_images/7/web/811000-811999/811123_7_full.jpg

[ace240sx]

S14DB what tranny do you have(SR or KA) what are the problems you are having?

[S14DB]

I picked up a KA tranny used. It seems to go into gear fine. The input shaft has some in/out play to it. I would rather replace the syncros and seals then have it installed and have problems.

[ace240sx]

The in/out play is normal, because the input shaft isnt pressed on, it just rolls on a thrust bearing on the end of the mainshaft, and is positioned between two bearings on the mainshaft and secondary shaft, so it has some freeplay.

I would recommend you change the 1st&2nd synchro + baulk rings, 3rd&4th synchro and baulk rings, bearings if there is high km, but it is not neccessary. The 5th and reverse are usually not needed because they are not high wear parts.

I would order oem Nissan parts, not some off brand from china. You dont want to screw around, and cut corners with parts such as these. I would order them from courtesy-nissan.
http://memimage.cardomain.net/member_images/7/web/811000-811999/811123_8_full.jpg

Here is the schematic that courtesy-nissan uses
Specify what tranny you have and then you will need 32605S, 2x32604M, 32601S, 32604, 32604Q, these are the 1/2, 3/4 synchro assembly and baulk rings. Also when you order ask for the front/rear seals they are like $5 each.

[S14DB]

I was told it was a 98 with 70k. It's got the OBDII trigger on top. What's the est cost of these?

Do I need:
EXTENSION HOUSING SEAL
RING GEAR
Housing Bearing
Just random crap I saw listed...

[kandyflip445]

Lets stop the crap talking and try to get things straight.

You just have to understand powerflow through the manual transmission.

The power goes in the input shaft>the countershaft>the selected FLOATING speed gear>the syncro SLEEVE>the syncro HUB>which is splined to the outputshaft and out.

When you select a gear you're moving a shift fork that is wrapped around a SYNCRO SLEEVE. In your first picture on this page it would be the thing lying on the left. The syncro sleeve moves over the blocking ring, the inserts (which you left out in the pic, they go where the three grooves are around the syncro hub) push the blocking ring forcing it onto the FLOATING SPEED GEAR SHOULDER which is a cone shape fitting in the blocking ring. The blocking ring (the brass ring) has sharp grooves on the inside of it that make contact with the FLOATING SPEED GEAR SHOULDER bringing it up to speed. If you look on the second picture you can see the grooves I'm talking about. When contact is made and you slide it in gear the SYNCRONIZER SLEEVE goes over the BLOCKING RING and then over the FLOATING SPEED GEAR TEETH locking the floating gear to the SYNCRO HUB which is splined to the OUTPUT SHAFT.

The SYNCRO SLEEVE won't grind against the BLOCKING RING because they're one unit and the SYNCRO SLEEVE just slides over it. The SYNCRO SLEEVE grinds against the FLOATING SPEED GEAR when the BLOCKING RING is worn on the inside sharp grooves, not allowing it to come up to speed.

[kandyflip445]

S14DB: You'll have to inspect everything when it's apart to determine what you need. You will need gaskets on the sealing surfaces that have one and you take apart. Vaseline is a good assembly lube because it will mix with the tranny fluid without harm. It holds bearings on the shafts well and inserts in place also. Post pictures up when you have the thing apart and make sure you have everything WELL organized.

[ace240sx]

The 32605S sells for $53.22 and the 32601S is $ 88.63. Baulk rings are about $30.00 each, seals $5. I recommend changing what is specified above, do it properly the first time, and in the future you will be glad. So roughly $270.