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Discussion Starter · #1 ·
Nissan Patrol 1986 highroof
Hello, i have a rather strange issue with my 5 speed gearbox. Nothing that keeps it from running but its getting really annoying and kinda takes away some of the joy driving this machine.
When i start the car in the morning, the gearbox easely goes into gears and shifts smoothly, takes no effort at all, and can shift gears quickly. as i keep driving and the the temps rises its getting more tight and feels like it dont want to mesh into gear. From 3rd to 4th i have to hold it into fourth and wait for it to mesh, apploying some force. This issue is on every gear. Ive also noticed when the engine is cold, it revs down alot quicker to idle after i engage the clutch so i thought this could be the issue, but i have tried waiting for idle then changing gears. Still a struggle to sh

I鈥檝e tried replacing slave cylinder, master cylinder (all new parts) new and flushed fluid.
I allso tried to adjust the clutch pedal to give it some more leverage to the pressureplate. No difference.

Then i saw some guy on this site commenting about changing to a thinner gearboxoil, so i did. No difference. I would assume it should be the other way, that thicker oil would allow a smoother gear mesh? Could this be the issue that my gearboxoil was originaly thin, then i changen to the same stuff?


In the mornings here it could go down to -35 celcius and the shifting is just awesome and easy, but as i drive 10 minutes it starts getting worse. Any ideas? Sorry for the typos. This was written on an iphone with cold fingers 馃ザ
 

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GU8 CRD
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Try changing the bushes where the gear lever connects. My daughter's had a similar problem and we also found the rubber boot damaged and dirt had got into the mechanism (and water into the box as well). Giving the area a flush with motor oil (the gearbox oil doesn't seem to reach it too well), new bushes and a couple of flushes seems to have been the fix for it.
 

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Discussion Starter · #3 ·
Thanks for the reply. But im pretty sure it cant be the bushings. When i shut the engine off, it takes absolutely zero effort to engange gears


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nissan
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Does the clutch pedal feel the same when it's hot and cold? It certainly sounds like clutch drag but it's often hard to determine the root cause of that.

Has the clutch/pressure plate ever been changed? How many kms on the vehicle? Does the slave cylinder have a heat shield?

Edit: TBH it sounds like a stuffed pressure plate to me and the only solution is a replacement which isn't cheap and a whole lot of work. The temper goes out of the diaphragm fingers with age and number of heat cycles. They become less stiff and flex more allowing a large movement of the throw out bearing but only providing a small movement of the pressure plate which continues to drag on the clutch plate. This is less of a problem when cold because the steel is stiffer when cold.

If clutch drag is the problem then you should be able to check that by matching revs at gear changes. This is easiest to do in the higher gears. Instead of letting the engine drop back to idle at gear changes only let it drop back to the revs it would be at when engaged in the next gear. Do the same on down shifts by increasing engine revs.
 

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Discussion Starter · #5 ·
I dont remember the results of rev matching. Kinda gotten used to it so i cant remember. But wil definetly try after work. Kms on chassi is 350k. Engine and gearbox? No clue. Could be the fourth engine and second gearbox for all i know. These cars are extremly rare here and 99% of them are unregistered offroad vehicles.

If i remember correctly there is a tiny bit of a hissing noise from bearing when clutch pedal is enganged. A clutchkit comes realy cheap, and gearbox down is no issue. Just need to wait for the summer heat, so i dont die


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nissan
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Engine and gearbox? No clue. Could be the fourth engine and second gearbox for all i know.
These are incredibly robust engines and gearboxes which regularly last past 500,000km so the engine and gearbox are probably original and the clutch probably is too. I changed mine at 290,000 so doing yours at 350,000 should not be unexpected.
 
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