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D21 4cyl 4x4 trans upgrade?

Posted: Mon Apr 29, 2019 5:36 pm
by Datsuntech
Bear with me as I write a book...

A few years ago I picked up a Japanese 1992 4dr D21 Nissan Datsun, TD27T, 5-spd 4x4. Soon after I got it I noticed a bad noise from the front of the trans. When I took out the trans the input shaft seal had failed and the input shaft bearing was toast. While tearing it down I found that the needle bearings in the input shaft were pitted and had wrecked the input shaft and the end of the mainshaft. Rather than replace all of that I found a rotted truck with a bad engine but a newer rebuilt trans in it. Being from a Z24 powered truck the case front had to be changed to fit the diesel. I took the trans apart inspected everything replaced the seals and gaskets and put it back together with a new clutch.
All good...
Fast forward to a few weeks ago I'm on the highway and bang! No 5th! Crap Ok try 4th, yup that works slow down some more, no 3rd...
All I have is 4th/direct no other gears or reverse. Well 4th got me to my destination but when I stopped I noticed oil coming out of the bellhousing so the input shaft seal is toast again and most likely the clutch. I haven't had time, nor desire to pull this trans to see just what went wrong but this is the second trans on this truck with only a little over 130,000 kms. I use this to tow my camper and my cars around on a car trailer. When the trans blew up though I was unloaded and just cruising along.

I write all of this to ask. Has anyone upgraded the trans on the back of the diesel? FS5R30 from a V6 Pathfinder?
I have never blown up a FS5W71 in any of my 2wd trucks or even in my 510 that I drive the crap out of, but this truck continues to eat transmissions.
Suggestions??

Re: D21 4cyl 4x4 trans upgrade?

Posted: Wed May 01, 2019 1:14 pm
by Bow_Tied
Welcome to CNTC!!

To be honest, few, if any, members here have JDM diesels.

Were you towing heavy loads in 5th typically? Were the loads in excess of the rated capacity for either gear box?

When you swapped transmissions, did you replace the pilot bushing/bearing? This is my first consideration as to what would cause input bearing failure, well, next to low oil in the trans.

Re: D21 4cyl 4x4 trans upgrade?

Posted: Wed May 01, 2019 5:13 pm
by Datsuntech
The truck itself other than the engine and bell housing bolt pattern is basically the same as any 4cyl 4x4 D21. I have towed lots but not long distances. Typically under 150kms with my camper 2500lbs and my car trailer around 4500lbs max for usually less than 100kms. All of this on flat prairie. When it did blow I was 700kms from home empty with literally no warning.
I did replace the bushing along with the clutch and release bearing. I probably had no more than a few thousand kms on that setup, but it was an unknown used trans that I used to replace the original trans.
On the subject of used, when I pulled the trans for the first time around 128k someone had already been in there as there was orange rtv all over the gasket for the input shaft cover. The truck now has barely over 130k and this will be the third time the trans has been out.

I own three JDM vehicles and what I've noticed is that low km vehicles from Japan have typically led a rough life. The clutches are usually toast and the transmissions are worn. This is probably from sitting in bumper to bumper traffic for long periods or driving the crap out of them. Who really knows...

As far as oil goes I filled it with the recommended GL4 oil and over filled it slightly as per TSB# NTB97018

This failure is definitely not input shaft bearing as there was no noise only a lurch and then all gears but 4th went. Eventually I will pull it apart to see what happened, but sort of not motivated at the moment.

Re: D21 4cyl 4x4 trans upgrade?

Posted: Thu May 02, 2019 1:58 pm
by Bow_Tied
Sounds primarily like bad luck. :/

Post some pics of your rig! :)

Re: D21 4cyl 4x4 trans upgrade?

Posted: Thu May 02, 2019 8:57 pm
by Datsuntech
Here she is.Image

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Re: D21 4cyl 4x4 trans upgrade?

Posted: Thu May 02, 2019 11:02 pm
by the x kid
Looks cool.


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Re: D21 4cyl 4x4 trans upgrade?

Posted: Thu May 02, 2019 11:30 pm
by Bow_Tied
sweet!

Re: D21 4cyl 4x4 trans upgrade?

Posted: Sat May 04, 2019 11:21 am
by Adam
I would try and find a trans from a v6 pathfinder/hardbody. First gen Xterra would also work as well as 96-2000 pathfinder with the vg33. But I believe the gearing is a little different on the later ones (both auto and stick shift). I know I put a 2004 Xterra automatic in my 94 pathy and it was great. But 1st gear was longer so I had less take off power.

FYI the manual ones were only rated to tow 3500lbs at least on the gassers. The automatic was good for 5k. Someone who worked at Nissan once told me it was only so they didn't have to warranty clutches.

Re: D21 4cyl 4x4 trans upgrade?

Posted: Sat May 04, 2019 11:37 am
by Datsuntech
That's my goal, but with the TD27T I have to use the original front case half as the bolt pattern is different than the KA24 that this trans (FS5W71C) normally came with. And the VG30 also has a different bolt pattern. So if I could find a front case half with the TD27T bolt pattern that fits the V6 trans (FS5R30A)Then I'd be good. As I have everything else. I have my own personal wrecking yard. Image

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Re: D21 4cyl 4x4 trans upgrade?

Posted: Sat May 04, 2019 11:44 am
by Datsuntech
Adam wrote: FYI the manual ones were only rated to tow 3500lbs at least on the gassers. The automatic was good for 5k. Someone who worked at Nissan once told me it was only so they didn't have to warranty clutches.
I am a former Nissan Tech through the 90s and early 2000s. I agree completely with what the other guy said.
I've towed many a heavy load with my 2WD 4cyl trucks and never had any trans issues. The FS5W71C is plenty strong, but the FS5R30A is stronger. I'm just sick of doing transmissions on this thing every second oil change... Image

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