Transmission Rattle in Neutral or Clutch Drag (1 Viewer)

[DesertFJ40]

Hello everyone,

I've been having a lot of weird things going on with my 4-speed conversion into a 1971 fj40. Everything worked fine for the first 100 miles. The issue began when I try to shift from 3rd into 4th gear. It's an early style h41. In order for me to properly shift into gear, I would have to shift very slowly to allow the synchro-rings to catch up so I could get a smooth shift. Not a big problem there. Well, just now, if I try to do the slow shift, I get lots of "clanking" noises and the shifter starts to vibrate a lot while I put the transmission into neutral during the gear change from 3rd to 4th. At this point, I just keep the clutch pressed, since it sounds like it wants to explode, and I coast it to where I can pull over safely and stop. I let go of the clutch pedal and leave the transmission in neutral. Still, the shifter is vibrating and you can still hear some slight "clanking" noises.

now that the vehicle is stopped, with no foot on the clutch or gas pedals, if I move the shifter up or try to pull down into a gear, the vehicle starts to creep forward about an inch. Its as if somehow, the clutch is trying to grab even though the transmission is in neutral and the clutch pedal is not being pressed. I've been driving with the transmission tunnel off and I can manipulate the clutch fork and see that there is still play before it engages on the pressure plate fingers all while this is occurring. I can also see from the side of the bell housing that the throw-out bearing is not spinning or touching the fingers of the pressure plate while the clutch pedal is out.

What im planning to do tomorrow is:
Change out the top plate for another early h41 that I have. I've found a couple of forums, for diffrent vehicles, that say that maybe the shifter forks might be worn out and cause this issue. Originally, everything looked good inside of this transmsision as did the top plate. I saw nothing to signifiy anything was worn out and it all seemed tight and operated smooth outside of the vehicle.

2nd thing is to rebuild the cluch master and clutch slave cylinder. Currently, there are no leaks from either of the two. They are about 8 years old now and Im able to change gears smoothly with the vehicle off and me pressing on the clutch pedal.

All other clutch related components are new; pilot bearing, resurfaced flywheel, clutch disk, pressure plate, and throw-out bearing. They are all 3 speed clutch parts with a 4-speed bellhousing and 4-speed transmisison. I did make sure to check if my clutch disk is on backwards, and I have confirmed that it is properly oriented.


I know you guys like pictures, but its late at night. Hopefully I can get a video of this, maybe not while driving, but at least at idle to not cause further damage. Thanks for reading and any suggestions/comments you may have.

 

[B y r o n]

Sounds like you have air or lack of fluid in the clutch system. The clutch is not fully disengaged which is why it wants to crawl forward.

 

[pb4ugo]

Id 1st properly adjust the clutch per the fsm, then see how that does.

 

[mattressking]

Did you go under the truck and remove the inspection cover to actually see what is rattling?

 

[aging fleet]

Agree it sounds like an adjustment issue, the noise could be from the throw out bearing constantly riding on the pressure plate or possibly you're missing the return spring that attaches to the clutch fork.

 

[DesertFJ40]

Sounds like you have air or lack of fluid in the clutch system. The clutch is not full disengaged which is why it wants to crawl forward.

Hmmm, well I did have the clutch master and slave drained while I did the conversion. I went ahead and gravity bled the system and I saw no more air bubbles in the clear tubing that I had connected onto the slave cylinder nipple. I then pumped it and bled the system, like brakes, just to make sure no bubbles were present. Still, the weird thing is, I fully release the clutch pedal and i can reach down to the clutch fork and feel that there is the 3mm of play as per the toyota manual. Meaning that the clutch should be disengaged since there is no force being applied to the pedal down to the slave cylinder and fork. Would it be possible that the clutch itself is somehow still engaged even though there is no pressure on the pedal or on the slave?

Id 1st properly adjust the clutch per the fsm, then see how that does.

Clutch pedal and slave cylinder play was adjusted. The fork pedal play begins to engage onto the slave about 35mm down while pressing the pedal, I'd say that's about a quarter of the way down. When releasing the pedal, you can feel the clutch grab about 3/4 on the way back up. So i'm getting a high engaging point and that's normal for land cruisers. I know some people like the clutch to begin engaging on the lower end, but at that point, it doesn't seem like it would give the slave cylinder and clutch fingers enough range of motion. I had checked the pedal height, pedal free play, and clutch fork play about 10 times to make sure and still have the issue.

Did you go under the truck and remove the inspection cover to actually see what is rattling?

I did remove the cover and looked. The throw out bearing does not spin while i have it in neutral and the vehicle is running. I do not have the clutched pressed in at this time and it still rattled. I can then then push on the clutch fork, with my hand, and make contact with the pressure plate fingers. I cant push further down since it requires a lot of hydraulic force, but it is enough to grab and turn the throw out bearing in sync with the pressure plate/flywheel/crankshaft. When I release the tension, the fork goes back and the throw-out spins down until it stops. Nothing from under the inspection cover looks wrong

Agree it sounds like an adjustment issue, the noise could be from the throw out bearing constantly riding on the pressure plate or possibly you're missing the return spring that attaches to the clutch fork.

I do have the return spring on the slave. I've looked multiple times and can see that the throw out bearing is not riding on the pressure plate.

 

[DesertFJ40]

There's not much detail for the video. I went ahead and drove around and soon enough it rattled around really really bad. Even as I coasted down the road and clutch pedal pressed in with transmission in neutral. I limped it back home and parked it. All the video shows is the rattling sound. Imagine that, but 10-times worse while trying to shift gears. Yesterday it was worse when I parked and left it running while in neutral. I couldn't replicate it for the video.

I proceeded to take the top plate cover off and noticed some nice gold dust splattered onto it. After closer inspection, I could see one of the syncro rings had been getting chewed up. This was definitely not how it looked before I put it into the fj40

I then drained the transmission and could see a ton of gold flakes embedded into the gear oil. For now, it seems like it was only one syncro gear that got chewed up and I have a replacement for it when I do a rebuild. For now im gonna take everything out and start over from the pilot bearing back. I have another transmission that I can put in and see how things go. I've been reading online and a bad pilot bearing also seems like the cause for such catastrophe. Its not too well documented on ih8mud, but i've been able to find other people posting about it on other forums experiencing the same type of symptoms and led to them finding that the pilot was toast. Only taking it all out and checking might give us the answer, or maybe not. This was supposedly a brand new one and it's recommended here as the double wide Nachi 5202z bearing.

 

[Mark Jennings]

Question…..what type of gear oil, GL-4 or GL-5?

 

[DesertFJ40]

Question…..what type of gear oil, GL-4 or GL-5?

I'm using GL4 SAE 90. The brand is Car quest and I bought it from adananced auto a few years ago in a 5 gallon bucket. It's probably considered a "cheap" brand but there was no other straight SAE 90 oil to be found like the Toyota manual calls for. I had used it previously in my 3 speed column shift transmission with no operational issues.

 

[Mark Jennings]

I'm using GL4 SAE 90. The brand is Car quest and I bought it from adananced auto a few years ago in a 5 gallon bucket. It's probably considered a "cheap" brand but there was no other straight SAE 90 oil to be found like the Toyota manual calls for. I had used it previously in my 3 speed column shift transmission with no operational issues.

Well that brings up another question
….and the reason I’m asking, from the pictures, it looks like that 3rd gear synchro clutch is well worn, there should be a good size gap between the bronze clutch and gear teeth, the picture shows minimal clearance….
Question; did you replace the synchro clutches when you installed the 4 speed? And if you didn’t, any ideas on how many miles on the 4 speed before install?

 

[DesertFJ40]

Well that brings up another question
….and the reason I’m asking, from the pictures, it looks like that 3rd gear synchro clutch is well worn, there should be a good size gap between the bronze clutch and gear teeth, the picture shows minimal clearance….
Question; did you replace the synchro clutches when you installed the 4 speed? And if you didn’t, any ideas on how many miles on the 4 speed before install?

For the gear teeth, do you mean the small gray/silver gear teeth that are to the right of the bronze syncro (clutch?) Is that what you're saying has minimal clearance? I really have no idea though as to how everything should look as far as clearances, your suggestion made me curious. I've never rebuilt a transmission before, let alone this one. Everything seemed clean, unworn, and both input/output shaft showed no signs of use when I first received it back in 2019. All bearings were in place when I took the covers off to put on the gaskets a while ago. When I started to drive it, i believe the input shaft bearing was making some noise. The noise would stop if the vehicle would coast in neutral. This was before everything went bad.

I bought this transmission back in 2019 from Specter off Road and barely had the chance to install it within these past few months. I don't know where they got it from or the history behind it, but according to their website, this transmission was not rebuilt and only inspected for wear/tear. When I received it, it looked brand new. This is the 1969-1971ish h41 that is seen in some toyota manuals as " F-engine with 4-speed. " From what i've read, they came on the fj55.

 

[DesertFJ40]

Also since you asked, I began comparing both my transmission inside of the fj40 to the one i have waiting to be installed.



Something is weird. The first part of the video is the h41 in my fj40. I'm able to move the shift-collar into neutral and into gear (to the right) with some slight difficulty. Not as smooth as it use to be. When I put it back into neutral, im able to spin the collar and you can see some of the gears moving. To me, that seemed okay at the time. Now the second part of the video is the other h41 that I have. Moveing the shift collar from neutral and to gear is a lot easier than the one in my fj40. When I put the shift-collar into neutral, I can barely spin the collar or manipulate the gears. I can only spin it if I turn the output/input shaft by hand. Putting it into gear is much more difficult to spin. Why is the one in my fj40 spinning and the one I have out on the floor tough to spin? Which one is correct?

Now the strange part. I went back to the one in my fj40 so I could put the top plate back on so no dirt/dust could get in. I tried rotating the shift-collar while in neutral just for the heck of it. It was stuck in place! Nothing spun like it did at the beginning of the video. After moving the syncro ring by hand and some verbal persuasion, something loosened up and I could spin it. What is going on?!

Lastly, I compared the sycro ring to gear teeth gap that I think you're talking about. I manuipulated the shift-collar, right to left, several times to get everything into place as much as it could.

This first picture is the transmisison still in the fj40. Also, you can see there are some teeth missing on the gray gear to the right of the brass/bronze syncro. I assume that's how it should be, it looks exactly the same in my spare transmsison. I spun the gears enough to find that part with the missing teeth just to confirm.

Here is a photo of the second transmission. As of now, i've loosened up most everything on the fj40 so I can tilt then engine/transmsion back to clear the rear crossmember. It should be coming out hopefully by the weekend.