A couple months back I put keith's old tranny from his R50 in to my WD21. (I had bought it about a year ago and finally got around to installing it.)

I had only driven it once or twice since then and now that I lost my work truck I've had to fire her back up and I'm noticing some quirks with the tranny.

From what I can tell the tranny is only going in to 2nd gear. It's sluggish coming off the line, has great midrange but never shifts and runs at higher rpm's than it should at lower highway speeds.

I can manually put it in 1st and it deffinitely does go in gear and I can manually shift in to 2nd to get it off the line, but then it still doesn't shift in to 3rd or "D"....which logically means it's also not dropping in to overdrive since the OD switch has no effect on it.

Keith an I were both under the impression that the trannies were the same....and in fact the harnesses and everything were identical. I'm wondering now if maybe the sensors are different or something.

I have to pull the the t-case this week and swap the speedo ring gear on the output shaft (it's missing!?) and I'm contemplating puting my old tranny back in as it still worked but had a small delay when shifting it in to drive.

Just thought I'd look for some opinions in case this rings any bells...before I do all that extra work!

Any ideas? Could this be some kind of fail safe mode?

The auto computers are not the same, nissan changed the electronic on them in 95 I recall.

I worked on & replaced stuff on my 90’s pathy and 2k X and the speedo sensor in the tcases where different and so was the torque Converters. Wonder if the fly wheels are different also?

The flywheels are the same.

I used the newer torque converter, had to - the old one would not fit the new tranny any way.

I also used the old speedo sensor as well.


What i'm on to now is that this is some type of limp mode - ie. the tranny protecting itself because it thinks something's wrong.

One possibility is that since the speedo sensor isn't working that maybe the tranny is confused without a signal from it. I know the tranny computer receives a signal from the VSS but I'm not sure how critical it is.

Anyone know what the differences were in the electronics? Are the tranny computer connections the same - so I could drop in the later model computer?

He posted on AC that he had disconnected the main tranny harness while investigating something else and hadn't reconnected it. Problem solved.