Problems downshifting - Infamous Nissan

PFDSA · 11-25-2020, 09:53 AM

Hello everybody.

Recently started having problems with my manual transmission. When I stop the truck, have problems shifting into 1st or reverse. If I shake the shift around a bit, it eventually goes into shift.

While in motion, have no problem shifting up, but have a hard time downshifting into 3rd,2nd and 1st, sometimes it grinds a bit.

In addition, the pedal is starting to squeak really loud when pressed, and sometimes there's a rattling sound when in neutral. The sound goes away when I fully press the clutch.

Will get the clutch disc and pressure plate replaced as soon as possible, but should I be worried about anything else? Synchronizers?

It's a 1988 4WD Double cab D21 (PMD21) TD23 2.4 Diesel

EDIT: Bled the Master Cylinder fluid with brake fluid DOT 3 until it became clear, since the old one was complete black, but didn't notice any changes.

nunya · 11-25-2020, 10:25 AM

I would suggest the throwout bearing be replaced, and the fork that moves it checked. Your truck has a hydraulic master and slave cylinder?

PFDSA · 11-25-2020, 10:55 AM

Quote:

Originally Posted by nunya

I would suggest the throwout bearing be replaced, and the fork that moves it checked. Your truck has a hydraulic master and slave cylinder?

Thank you for the suggestion!
I'm a complete noob...any idea on how I check if it has a hydraulic master and slave cylinder?

PFDSA · 11-25-2020, 11:22 AM

Quote:

Originally Posted by nunya

I would suggest the throwout bearing be replaced, and the fork that moves it checked. Your truck has a hydraulic master and slave cylinder?

Just checked the list parts for this model and it lists in japanese a part called "clutch operating cylinder/ clutch release cylinder", could it be the slave cylinder?
This is the photo of the part
clutch operating cylinder

clutch release cylinder

Reserector · 11-25-2020, 06:51 PM

Yes, that would be the "slave" cylinder.

street_rulerr · 11-25-2020, 07:32 PM

bleed the slave. this is a classic sign of air in the line. when in motion the rotating speed of the input shaft vs gears kinda matters less. they kinda natrually synch. at a stop one is in motion and the other is stationary so you kinda need that full-clutch-engagement.

rockcrawls · 11-25-2020, 08:07 PM

First thing I'd check is the tranny fluid level. Top that off to the fill hole at least with real GL4 fluid. And I hope this doesn't turn into another long discussion on GL4 fluid. haha. There are lots of threads on here about that.

OldGreyBeast · 11-25-2020, 08:36 PM

If your truck has the clutch damper, that may be the source of the problem as well. The damper is located on the firewall. Mine was very leaky when I first got the truck and caused a lot of problems with the clutch. I eliminated it (as quite a few people here have done) then flushed the lines and replaced the master and slave cylinder. Makes a huge difference in clutch feel.

Deerhurst · 11-25-2020, 09:19 PM

Quote:

Originally Posted by rockcrawls

First thing I'd check is the tranny fluid level. Top that off to the fill hole at least with real GL4 fluid. And I hope this doesn't turn into another long discussion on GL4 fluid. haha. There are lots of threads on here about that.

GL4. Always GL4. Thou must always use GL4 and GL4 is what thou shall use!

I'd check the bleed. Noise could be a throwout bearing. If you go through the effort of replacing that just do the clutch and inspect the flywheel since you'll be there anyways. I have had vehicles that the fingers on the pressure plate rattle. My dirt bike has an automotive style clutch (2002 Gas Gas 280Pro) and it rattles like a tin can of marbles in neutral. It's the fingers flopping around.

Maybe an input bearing on the tranny? Throwout bearings generally make noise when used so when the pedal is depressed vs when the pedal is out like yours.

PFDSA, I'm not sure if English is your native language as your location says Japan but your English is really good!

PFDSA · 11-25-2020, 09:57 PM

Quote:

Originally Posted by OldGreyBeast

If your truck has the clutch damper, that may be the source of the problem as well. The damper is located on the firewall. Mine was very leaky when I first got the truck and caused a lot of problems with the clutch. I eliminated it (as quite a few people here have done) then flushed the lines and replaced the master and slave cylinder. Makes a huge difference in clutch feel.

Will definitely try that out!

11-25-2020, 09:53 AM	#1
PFDSA Join Date: Nov 2020 Location: Japan Posts: 31 Vehicle: 1988 Datsun Truck D21 Thanks: 34 Thanked 6 Times in 3 Posts	Problems downshifting Hello everybody. Recently started having problems with my manual transmission. When I stop the truck, have problems shifting into 1st or reverse. If I shake the shift around a bit, it eventually goes into shift. While in motion, have no problem shifting up, but have a hard time downshifting into 3rd,2nd and 1st, sometimes it grinds a bit. In addition, the pedal is starting to squeak really loud when pressed, and sometimes there's a rattling sound when in neutral. The sound goes away when I fully press the clutch. Will get the clutch disc and pressure plate replaced as soon as possible, but should I be worried about anything else? Synchronizers? It's a 1988 4WD Double cab D21 (PMD21) TD23 2.4 Diesel EDIT: Bled the Master Cylinder fluid with brake fluid DOT 3 until it became clear, since the old one was complete black, but didn't notice any changes. Last edited by PFDSA; 11-26-2020 at 09:10 AM.

11-25-2020, 06:51 PM	#5
Reserector the Flaming Marshmallow Join Date: Oct 2015 Location: Laurel, MS Posts: 1,572 Vehicle: Nissan HB KC 4x4 Thanks: 26 Thanked 381 Times in 302 Posts	Yes, that would be the "slave" cylinder. __________________ Becoming the Flaming Marshmallow * SAS * V8 Conversion * The FM "Z71 Conversion" Explained Vid * Ride-Along Vid

11-25-2020, 08:36 PM	#8
OldGreyBeast 1986.5 HB 4x4 3.0V6 Join Date: Mar 2012 Location: North AL Age: 33 Posts: 3,944 Vehicle: 86.5 Nissan D21, 87 Mercedes 190D Turbo, 10 Mercedes E350 AWD, 17 Honda CBR500R, 16 Suzuku GSXS1000 Thanks: 386 Thanked 484 Times in 423 Posts	If your truck has the clutch damper, that may be the source of the problem as well. The damper is located on the firewall. Mine was very leaky when I first got the truck and caused a lot of problems with the clutch. I eliminated it (as quite a few people here have done) then flushed the lines and replaced the master and slave cylinder. Makes a huge difference in clutch feel. __________________ Build log for the Beast - https://beastbuildlog.blogspot.com - Last Updated 18 OCT 2016 1986.5 FSM GI section - https://imgur.com/gallery/mjT18bV

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

11-25-2020, 10:25 AM	#2
nunya Join Date: Apr 2019 Location: Southeast Posts: 973 Vehicle: nissan d21 93 kingcab 2wd Thanks: 287 Thanked 217 Times in 180 Posts	I would suggest the throwout bearing be replaced, and the fork that moves it checked. Your truck has a hydraulic master and slave cylinder?

11-25-2020, 07:32 PM	#6
street_rulerr Join Date: Nov 2015 Location: West Coast Posts: 2,262 Vehicle: 1996 4x4 5spd Thanks: 0 Thanked 201 Times in 190 Posts	bleed the slave. this is a classic sign of air in the line. when in motion the rotating speed of the input shaft vs gears kinda matters less. they kinda natrually synch. at a stop one is in motion and the other is stationary so you kinda need that full-clutch-engagement.

11-25-2020, 08:07 PM	#7
rockcrawls Join Date: Jan 2018 Location: A bubble Posts: 259 Vehicle: 1991 D21 4wd 4cyl, Case 580D backhoe loader Thanks: 56 Thanked 32 Times in 31 Posts	First thing I'd check is the tranny fluid level. Top that off to the fill hole at least with real GL4 fluid. And I hope this doesn't turn into another long discussion on GL4 fluid. haha. There are lots of threads on here about that.