94 4 cyl automatic overdrive & lock-up

Kydiesel · Mar 17th, 2005, 09:18 AM

I have rebuilt 100s of transmissions but only a few nissans. checked the fluid and all the usual stuff. going to pull the pan soon though I don't expect to see anything wrong. I rebuilt this one at 130,000 the first time. it has the same symptoms this time. actually the unit shifts into overdrive at about 40 mph at light throttle then as you accelerate at 46 mph (about when lock-up should occur) it downshifts back a gear, lock up never seems to occur. just as if you had pushed the overdrive lock-up button in. The button works normally, light comes on and it downshifts at say 45 mph back a gear as it should. given this fact I think the lockout switch is ok and the clutches etc.. are ok. The first rebuild everything inside looked great. I put in a kit any way and a torque converter and that solved the problem. after about 6 months 30,000 miles later it did it again one day on a trip to lunch. that afternoon on my way home I got on it rather hard and let off and it shifted and has done so ever since, till yesterday! now at 240,000 it has done it again. no tell tail signs of warning just wouldn't go into overdrive and lock-up after I pulled through a drive through window it had shifted fine all day before that. I think I have an electrical problem, not the lockout switch I think I have ruled that out. Maybe a speed sensor? though the speedometer still works, maybe a temp switch, though the temp gauge still works, Maybe a gov trash problem, or valve body? and I am thinking really hard about the torque converter. That is the only part I replaced the last time that I really could not diagnose and believe was ok before I replaced it. I also have a friend that has an identical problem. He was on the way to the trans shop last week when his seemed to strip out something (non- related I think) he had been driving like that for 10,000 miles. so this seems to be a chronic nissan problem. Has anyone else seen this before??

Kydiesel · Mar 17th, 2005, 07:46 PM

Up-date It has been a while since I looked at the tranny it is a RE-4R01A I thought the E stood for electric but it seems this is a hydraulic transmission I still believe it has something to do with the lock-up maybe it looses pressure when it shifts and goes back to 3rd? still driving in 3rd...

**88pathoffroad** · Mar 18th, 2005, 01:31 AM

Run the TCU error codes.

Here you go. You're welcome.

http://wd21forums.damagedreality.com...topic.php?t=17

Kydiesel · Mar 18th, 2005, 09:23 AM

[quote=88pathoffroad]Run the TCU error codes.

Here you go. You're welcome.

http://wd21forums.damagedreality.com...topic.php?t=17[

I don't think it has a TCU since it is not an electronic transmission. No box under the seat just the one ECM. there are no shift sol, etc.. The only electric part is the TC lockout that recieves a signal when the accelerator is at idle and the Overdrive lockout that is attached to the button in the cab. I have checked and both are working. The truck is a 4 cyl. I think that is the difference, the 4 cyl pickup seem to have a different tranny than the pathfinders and the V6s Thanks though and feel free to correct me if I am wrong here. I plan on pulling it out today maybe that will shed some light. I am surprised that no one seems to have had this problem but me. This is my 3 rd time with this truck and I know one more in my area the same thing.

Kydiesel · Mar 21st, 2005, 11:59 PM

Well I took the unit out, just as I suspsected it looked great inside. even after over 100,000 the clutches still look good. there was metal and friction material in the pan though. so I suspect the torque converter. I ordered an rebuild kit and TC today That fixed it the last time nd I am sure it will again this time I just wish I really knew what part I was actually fixing in the process that makes it work again 100,00 miles.

**88pathoffroad** · Mar 24th, 2005, 12:12 AM

Man, that sucks. At least you have the experience and are able to do it yourself.

Kydiesel · Mar 27th, 2005, 09:36 AM

Quote:

Originally Posted by 88pathoffroad

Man, that sucks. At least you have the experience and are able to do it yourself.

Yep but didn't want to spend the whole weekend workin on it and my resources are limited here at home. took me about 4 hrs to get it out. I got it together now, will give an up date when I get it finished. $ 300.00 poorer Kydiesel

Kydiesel · Mar 28th, 2005, 11:45 PM

Well I guess this is my last post. I think I found the problem. after overhaulin the whole tranny with new clutches etc..and a new Torque converter I still had an overdrive problem. same as before. I had another nissan sitting in the garage right beside it so I took the valve body out of the doner and presto! overdrive and lock -up all is well. sure wish someone had discovered this before me. looks like the no overdrive and lock - up problem was valve body related. Now all I have to do is fix the old valve body and get my other truck going. it is a total I bought to replace this one it is ready for paint... Thanks guys"