lemmiewink

Ok, I have to delve into a little back story for people to get the whole picture. I'll try to keep it short. I have an auto to manual conversion.

About 2 weeks ago, my clutch felt like it was not disengaging properly and I could not shift into gear. When I could the car would creep, even when the clutch pedal was fully depressed. This happened within the course of a day. In the morning it engaged and disengaged. It was bled that morning as well. It was at night that it actually started behaving in this matter.

I had to, in deep sadness, force it into gear to get it home. Before I get home though I suddenly lose pressure from the pedal and it falls flat to the floor. I inspected the fork and I found out that my release bearing hub broke.

So I took off the transmission and replaced it with all new hardeware etc etc.

I finished it this past friday and the system was bled again.

Now, its as if deja vu was happening. Since friday morning it disengaged fine, but now at 130 in the morning as i drove home it started to feel the same as before. The engagement point is much closer to fully depressed now and I can't even get into reverse. It would just grind hard.

I have an sc300 master cyl also,bought new from the dealer.

What is goin on? Any tips and solutions would be great.

Thanks.

Asha'man

iTrader: (1)

Bent part maybe? Like either the clutch fork or the fork pivot point, maybe even the pressure plate fingers?

RyanV

iTrader: (9)

Is the clutch OEM? Many of the R154 OEM clutches are rebuilt by Toyota, but they are good as new.

It's a possibility that the crank is moving when clutch pressure is applied. Thrust bearing, aka crankwalk.

I can't think if anything else that would just start to occur after the car had been working properly for sometime.

Do you have a neutral safety clutch switch?

lexforlife

iTrader: (7)

check the clutch pedal adjustment , its a squareish roundish looking that the rod screws into.. same thing happened to me .. if the locking nut is not locked the rod can become jammed and give full travel to engage and disengage

lemmiewink

This morning I rechecked everything. Fluids, bleed, piston travel, and clutch adjustment. Including retighting the locking nut which i could turn by hand. If by locking nut you mean the nut right be hind the squarish rounding thing. This could possibly be why!

Now it engages and disengages beautifully.

God I hope I do not have crank walk. I have no neutral safety switch and always start it without pressing on the pedal. I try not to push it in and balance the 6 puck. I only press down for a quick shift. I guess I'll rais the idle to give the thrust bearing a little more splash.

I love this community!

RyanV

iTrader: (9)

lexforlife FTW!

Glad it's working again!

lemmiewink

Tonight it did almost the same thing. Except it doesn't creep, so I know the clutch is disengaging fully. But its very hard to shift into reverse. It jus grinds in there. Sometimes the other gears also grind, very minimally but are somewhat harder to shift than it was in the morning and all day until 12 am. WTF why does it only happen at night?

I'm using penzoil synchromesh in my transmission though. Maybe thats the problem? I don't know.

lemmiewink

Later on this morning I tried it out, and it shifts perfectly. I'm really stumped on whether there is something wrong or its just part of normal operation.

lemmiewink

Problem is back again. WTF is going on? I changed the fluid from penzoil synchromesh to royal purple 75-90w. At first it shifted fine, but after leaving it alone for a few hours it will do the same exact thing! Very hard to shift into gear, and heaving grinding in reverse!

Please I need help asap. What could cause intermittent problems such as this?

BTW this is a JDM r154 if that helps any.

lemmiewink

It actually felt better with the gm synchromesh. At least when it warmed up it would be able to shift better. With royal purple, it seems that even when warm its hard to shift.

lemmiewink

Ok changed it to redline mt90! Feels like new again. Hope it works in the long term. will report back with findings.


Also. some posts from supramania while I was doin research on the subject.


"The cliff notes version is the R154 and W58 trannys NEED a certain amount of friction to work properly. RP Max-Gear is *too* slippery to provide this friction...RP Synchromax is even more so. It is more an ATF type lubricant and thins out significantly at higher temps. IMO, these 2 gear oils are not well suited for our manual trannys...the success many guys have seen using these oils is due to the slippery characteristics of these gear oils "freeing up" (reducing friction) parts in the R154/W58 that are on the way to failure. This is not fixing the problem...that sound from your tranny is the sound of inevitably.



The reason more modern trannys spec a gear oil like Synchromax (or GM's synchromesh) is to improve cold shifts. The thicker oils in a GL-4/5 category do not shift well at lower temps...they need to warm up. The problem is Synchromax does not have the extreme pressure protection, oil film thickness, and shear stability required...this will increase wear on the gears. Synchromax may help quiet down a worn R154/W58 for a while, but it is not really helping the problem...it's masking it.



uote:
With most lubricated components, the slipperier the better, but this is not so with manual transmissions. The synchronization of shifting gears requires friction to transfer energy from the synchronizer, which is locked to the input shaft, to its mating surface attached to the gear to be locked in as the drive gear. The drive gear is selected by using the shift forks to slide a synchronizer ring, which rotates at the same speed as the input shaft, in contact with the selected drive gear. Once the drive gear is brought to the same speed as the input shaft, the locking ring on the synchro assembly is allowed to slide over and lock into the drive gear. The time this process takes depends on how easily the synchro ring moves and the rate of frictional energy transfer between the two synchronizer surfaces. Higher viscosity lubricants slow the sliding of the synchro ring on the input shaft and require a longer time for the oil to be squeezed out from between the mating synchronizer surfaces. After the lubricant is squeezed out, the coefficient of friction of the lubricant determines the rate of frictional energy transfer between the two surfaces. Slippery lubricants such as hypoid gear oils (like RP Max-Gear) can take too long to synchronize the gears, which promotes synchronizer wear. Red Line MTL and MT-90 has a coefficient of friction which is greater than conventional oils, allowing a quicker transfer of frictional energy."

This is from a member named "jdub" who is a mod there and under his name is. Official SM Expert: Motor Oil, Lubricants & Filtration

Another quote commenting on why royal purple may "seem" to work at first. From the same person

"In any case, the point is Synchomax is much too thin for either tranny. Max-Gear will work, but the friction modifiers can cause problems with the syncros on a tight tranny. IMO, the improvements guys see using either RP product come from freeing up worn syncros...the tranny is on the way out and the frictions modifiers grant a reprieve. It's not a matter of if the tranny is going to fail, it's when. But if it works and puts it off for a while, it's a viable technique...I'd save up for a new tranny or a re-build though"

dejacky

iTrader: (2)

lemmiewink,
please keep us updated on if the MT90 works in the long run, I'm curious if the culprit is something else...

lemmiewink

Definately. I just test drove it an hour after I took the initial test drive. Seems to be holding up well. Shifts so smooth. Will post findings after I leave it alone for more hours

lemmiewink

Still holding up really well! I think this is working. I'll test drive it right now.

dejacky

iTrader: (2)

status update?