Need Old Nissan Auto Transmission Help

Roger McDaniels · **Posted:** Mon Apr 20, 2015 10:07 pm

I've got an '87 Sentra with a RL3F01A that won't shift to 3rd. 1st-2nd work fine, but it never tries to go to 3rd. It's a 3-speed with a single servo/band, internally controlled with only a kick-down cable for an input. Based on 1st-2nd working, I'm thinking it has to be in the valve body, but I pulled it apart and it looks good and everything operates smoothly. I'm thinking of going junkyarding for a valve body, since a bunch of old Sentras/Stanzas/Pulsars used this transmission and it takes all of 5 minutes to pull the valve body, but I figured I'd post here in case I'm overlooking something.

I wouldn't be averse to paying someone who's good with these to fix it if you know any old Nissan gurus, but I only paid $300 for the car, so I'm probably not going to be looking to pay very much.

RodneyWright · **Posted:** Mon Apr 20, 2015 10:36 pm

call Rex Deffenbaugh over at Happy Japs. He might be able to give you some insight.

233 E Johnson St, Cary, NC 27513
(919) 467-2884

Chad Culbertson · **Posted:** Tue Apr 21, 2015 8:30 pm

Does it have a governor or anything in it? I know old chevy transmissions had a governor that was gear driven to some spring loaded weights that determined shift points and such.

Also, is the linkage adjustable by chance? Wonder if it's possible it's actually in 2 if it has it, guessing you should be able to feel that when shifting it anyway, plus R-N-P would probably be off too.

Just some extra ideas, otherwise I know nothing about Japs, lol.

Roger McDaniels · **Posted:** Tue Apr 21, 2015 10:42 pm

It has a governor in the valve body that's pressure driven, or maybe 2 governors, I'm not sure. My automatic transmission Kung Fu is weak. It's operating the 1-2 shift valve. It just doesn't operate the 2-3 shift valve. I already checked the linkage and adjusted the kick-down cable. I even disassembled the valve body and cycled all of the valves manually, and they operate smoothly, but a valve body looks like a negative of a pile of spaghetti to me, so I'm probably doing something wrong.

Chad Culbertson · **Posted:** Wed Apr 22, 2015 8:33 am

I know some valve bodies have little check balls too, if it lost one of those somewhere it might be an issue. It seems like maybe a valve body might do the trick, perhaps it's clogged up in one of the tiny passages somewhere?

RickyBeam · **Posted:** Wed Apr 22, 2015 3:48 pm

As our rallyx toy, do we *really* need it to go more than 45mph? I'm just sayin'.

("want" maybe, "need" or "should" probably not. Yes, at VIR, there are places where cars can get "exceedingly" fast -- usually headed into a tree or 90deg turn.)

Roger McDaniels · **Posted:** Wed Apr 22, 2015 6:48 pm

It's more the RPM than the speed. At 45 the engine is screaming and bouncing off of the rev limiter. I don't know how much of that it can take.

Roger McDaniels · **Posted:** Thu Apr 23, 2015 2:45 pm

This may be fixed. I stopped by LKQ today and they had a 1987 Nissan Pulsar (same transmission as the Sentra) with an automatic that was relatively intact. I pulled the valve body and put it next to the Sentra valve body. The first thing that I noticed was that the Pulsar valve body was filthy, covered in black crud and the filter was jammed with bits of clutch/plate metal and disintegrating cork gasket material, much like I'd expect an '80's Nissan valve body to look, while the Sentra valve body had looked very clean when I pulled it. Then I noticed that the Sentra valve body was missing a couple of obvious parts, like a valve return spring and one of the bolts that clamps the halves halves of the body to the separator plate. There may be more discrepancies, but I never opened the Pulsar valve body (didn't feel like messing with it); I just put a new filter on it and wiped off the obvious external crud. I didn't want to run the car for long because I've got the water pump belt off of it (waiting for a power steering part), but I fired it up with the Pulsar valve body in it and revved it up, and it went to 55 MPH without hitting the rev limiter (front is off the ground on jack stands, didn't actually drive it anywhere), where before it would only go to 45 before it started bouncing off of the rev limiter.

I think that someone may have worked on it before and not put it back together correctly. When we got it, the prior owner just told us that it would no longer go in to 3rd gear, so we don't really know anything about the car's history.

Roger McDaniels · **Posted:** Tue Apr 28, 2015 11:24 am

And that didn't fix it.

I finally ordered the ATSG service manual for the transmission. It has exploded diagrams, diagnostics, valve body schematics, and overhaul procedures. It cost $30, but it was worth it. I ordered it as a downloadable PDF, so I got delivery within a few minutes. Following the diagnostic procedure led to this:

Chad was correct, there was a mechanical governor and the gear was stripped. Apparently it was never shifting to 2nd. I felt it do something that changed the RPM, maybe high and low clutches? I don't know enough about it to say.

A quick trip to LKQ and $11 for the mechanical governor out of the Pulsar (one bolt, takes about 30 seconds to remove) and it shifts now. Driving this thing jacked up in the air on snow tires with a very questionable alignment at 70 MPH is exciting.

Chad Culbertson · **Posted:** Tue Apr 28, 2015 11:52 am

Possibly the torque converter locking up, although I would imagine after 2k rpm or so it should be locked up, but maybe without the governor working properly it wasn't locking up till higher rpm.

I'm not an automatic expert, however I did manage to rebuild my own 700R4 in my 85 Chevy pickup and only had to pull it back out twice, lol.

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Need Old Nissan Auto Transmission Help

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