NissanDiesel Forums

About a month ago I replaced my transmission with one of my spares. It would appear I ruined it this past winter by being a fool with it 'bump' starting it in my friends well sloped driveway. That's what I suspect, anyway, as I never had any sound from it until after I did that a few times. The last day I drove it before removing it, it was singing me a multi-toned whine together in every gear except 4th which leads me to believe I damaged the layshaft cluster bearings and/or cluster drive set. Lesson learned.... Don't piss around bump starting in any gear but maybe 4th...

One good thing I found out. The clutches in these trucks are excellent. I've been driving this thing since 2004 and the clutch disc still had the words 'flywheel side' still legible on it and not even fully broken in yet. Still had some virgin surface left on both sides:-).

Seems like it was just yesterday that I posted about replacing the transmission. Well..... going again. Thought I noticed a change in the feel and sound, so decided to change the fluid. It came out as a nice grey chunky soup with pieces of bearing cage leading the way. My remaining spare also yielded a piece of bearing cage. Man, these trannys are a pile of cheap crap. Anyway, on Monday am going down to the transmission re-builder who tells me he may have one. More to follow...

N_R

For those just tuning in . . .

The front countershaft (layshaft) bearing is weak for the diesel application, until it got beefed up in 1985.

The reverse gear will die if abused much.

The nut retaining the 5th gear on the mainshaft can come loose.

Those are the major weak points of this 25-year-old transmission.

More info in this thread.

Well things are not looking too great. The tranny that was brought in was disassembled at my insistence and turned out to be scrap. It had been run out of lube. Brought down my one remaining spare which I know has eaten a bearing. They'll see what they can do with that. I have to juggle all this in addition to using my dying truck to go to work since I have no other vehicle.
More to follow as it happens....

N_R

Well, My second spare transmission turned out to be repairable and I picked it up last night all ready to go. They changed the bearings and it was the layshaft front bearing that had gone and all of them worn. They loctited the 5th gear nut as I requested. They told me that it was in pretty good condition except for the bearings. So... this weekend will change the tranny and I will do the taken out tranny at my own leisure. 150.00 for the bearing/seal kit and there apparently is one set left at the supplier after which no more will be available from him. No problem. I think I'll just match it all up at a bearing jobber and maybe see about replacing the front bearings with a heavier duty variety if possible.

More to follow...

N_R

The transmission is installed and seems to work well. It is running in synthetic blend 80W90. No noise at all and the neutral clatter is even much more subdued. Everything is nice and tight. Synchros are really good in this one. I'm gonna have to play with some rubber pads under the crossmember mounts as there is a body vibe in low second and low fifth. It used to be in high 4th. Funny how each time I disturb the mountings, the vibration moves around. I'll post again when I tear the old tranny down and for now, the world is back in order.

N_R