Transmission suicide at 70mph

[oaky8]

My tranmission sh*t the bed yesterday. Maybe you all can help me figure out what i need to replaced. 98' 4wd 3.3 pathfinder LE with 4spd auto

 

Last night i was on my way home from a 1400+ mile round trip. FL to LA and back to FL. Half way through the drive back it seems that the trannys dropped 4th then re-engaged 4th. So quickly that it almost felt like a bump in the highway. I continue on cautiously (never stopped) nothing else weird happens until... I have to stop and crawl in mobile traffic through downtown mobile. It then starts making noise. 1-2 shift point moves up in rpm range from 2k to 3k. Once across tunnel i hear a constant noise that sounded as if it was coming from rear differential. It went away after a while maintaining a constant speed. Also when accelerating the transmission made noise but when off throttle it would subside (this was only for a short time did not happen again). A while later I stop for gas. As i slow down to stop and then later pull out to get back on road the transmission starts making a noise, feels laboured, and like its slipping. The noise from transmission sounds like something is spinning and rubbing on something else. On another car I once had a bent splash/heat shield rubbing on a drive shaft and it sounded a lot like that. Its not VERY loud but the radio would have to be pretty high to drown it out. I checked under and nothing is leaking. Temps are fine. So i decided to baby it home (another 300 miles). 1st sounds bad, slammed into second (high rpm and way harder than usual) 3rd sounds bad, and then slams and shutters into 4th. I hit the overdrive button and it drops to 3rd where the noise is almost gone, i drive like this for a few miles then press the button again. It goes into 4th without a slam and doesn't start making noise. I continue fighting it the entire way home, every time getting scared that it will not move after slowing down or stopping. The noise and problem was only present when not moving in 3rd or 4th gear. If the noise did start it would go away after driving for a few miles. But then i got off the highway one last time and on that very exit ramp the tranny completely died after stopping for the signal light. I had selected neutral when slowing down on the exit ramp this might of broken its final leg. Luckily i was only a few blocks from home and i got towed. This morning i started the car, put it in drive and it made the noise but would move. I didn't drive it anywhere just rolled forward and back a few feet.

 

So my question is where do i look first? I suspect the first hit i felt was a slip of the torque converter which caused strain on the rest of the system. I also suspect something broke off somewhere because of the noise. I know of a 2wd pathfinder where i can source parts but i'm not sure if 2wd and 4wd have the same transmission. The shift from 1-2 has been a light hit for a few months, but everything else has been normal. Checked ATF today its full and red without any flakes on dipstick. Maybe a slight burn smell but I have never smelled good vs bad atf before so im not sure. There was a film of atf on the lower bell housing on starter and on fluid cooler lines. But it was not a fast leak so i couldn't trace it. I assume torque converter and entire tranny will have to be swapped.

[oaky8]

.... now i think this will become an automatic to manual swap thread. I will be following this god send walk through. Since the automagic gave out and i need to replace it anyway I will attempt to swap in a manual. I have found the 5 speed at a bunch of local salvage yards. But these places aren't really that cheap. So I will first look for a u-pull it type of deal. That way I can get all parts i need in one parts run. (my second car is an 80's rx7. so im not sure how ill drag a tranny home). If i can't find a self service parts yard manual pathfinder i will make calls to the salvage yards and sweet talk them into cutting me a deal for buying a bunch of parts.

 

Questions for you pros;

Will the car run without the manual ECM? I read that it just turns off the service light, but thats on from a cracked header anyhow.

Will my current automatic transfer case fit a manual transfer case? are they all the same tx-10?

Can i pull the manual wiring harness? Seems like the walkthrough wants me to splice wires but I'd feel better just putting in a proper nissan oem wire section.

What does tranny + transfer case weigh?

[adamzan]

I think It will run fine without the manual ecm. But it might not cost that much to pull the one from the donor. Transfer case I'm not sure about, I would just grab the whole deal from the other truck and use that. Then you don't have to mess with splitting the two. They are all tx-10 though unless you have the electric switch and not the floor lever.

 

My auto and tcase weighed probably 250+ lbs. It took 3 of us to lift it and the new one.

[oaky8]

Of course if i could find the ecm and tranny and everything in one car i would get it. But i worry that i will have to source parts from a few different vehicles. I have the floor mounted 4wd select. None of the electric switch stuff.

250lbs is a lot. Dont think i can fit that in the rx7.

 

I read that the gears are shorter on the manual. I would really like for the pathfinder to be able to cruise at 80mph without having to be at 3K rpm. Is there any other gear set i can swap in or should i just look at doing a rear end final drive swap? I hardly use the 4wd or go off road so i don't especially need short/low gears. I would rather highspeed highway cruising.

[jyeager]

Sorry to ask this, but you don't mention checking your tranny fluid level.

 

 

[oaky8]

And we are back to just a automatic swap. I couldn't source all components needed for manual swap. Would be more expensive for the manual swap. With the prospect of doing some off roading and overlanding in the next year i think it will be easier to highway travel and off road with an auto box. Torque converter holding all the power makes wheeling a lot easier.

 

I got an auto tranny from a u-pull-it place. i suspect 200K + miles on it compared to my r50 with 151K miles. since odometer is electric and batteries aren't left in cars i couldn't tell. I learned a lot by dropping that transmission first. Will make removal of my cars transmission easier and quicker.

Since the replacement torque converter is probably old and maybe worn i want to make sure its even good. In the FSM i saw a tool for testing. I dont have that tool. Do transmission shops generally have equipment to test the usefulness of a transmission? Would hate to install entire transmission to find it slips as well. At this point i feel that the replacement tranny might be a crap shoot.

some tricks i learned

1) remove transfer case floor transfer case shifter handle BEFORE dropping tranny

2) the top two transmission/engine bolts are a pain to reach. Drop the transmission crossmember and the entire engine/trans will tilt back giving you more room to work. Bolts can be reached through interior tranny tunnel hole, or from underneath. Make sure to have a universal joint and 2+ feet of extensions.

3) its almost impossible to reach the 4 14mm bolts that hold torque converter to flexplate. A flat combination wrench or crows foot socket would be useful. Could not use a standard socket. Not sure how i will bolt these on for re-insall much less to spec torque

 

While im down here I will replace the rear main seal. Dont think its leaking since i notice no fluid level change during oil changes. But posterity I guess.

Are there any other seals i should replace? Some oil does leak then burn on header out of the valve cover, that seems to be very common. I smell a hot oil burn smell often when idling after a drive. I assume this is the source of that smell.

 

 

Sorry to ask this, but you don't mention checking your tranny fluid level.

 

 

yep, I checked it the next morning. Its part of the original post, second paragraph. I pulled the drain plug on tranny fluid last night and it looked pretty black. Wasn't a lot of light out so i couldn't see through stream, but i didn't see any red to it. However on the dipstick the fluid was very red and looked completely normal.

[kdj]

Did you find out why the first one failed? Plugged cooler, lines, filter maybe low fluid from a leak? Normally they just don't fail, one thing causes them to fail. I'd stay with a auto. sorry if I missed anything in first post. Tighten up the valve covers a "bit". Clean things up and see if and where the oil leak comes from. While you have it apart its the best time to track down things like that.

[fixinto]

i would check the lines before i bolted up the new one. make sure they flow proper from trans into rad, and back out of rad through the line that runs back to the trans. Oil leak is uber common. Try tightening the rocker covers half to 3/4 of a turn. seems to work for a lot of the guys, although it didnt for me. had to pull the upper intake to change them out. They were like hard plastic instead of rubber. Probably original. If you do decide to address it, would be a really good time to change your plugs. "dreaded number 6" u know.

About the seals. I would probably do a front and rear seal on the salvaged trans. and do a fill and drain with some el cheapo auto trans fluid before bolting it up for the last time and topping it off with whatever your going to use. Like you were thinking, its probably not a bad time to change the rear main while your in there. I suggest At least some blue lock tite on the converter bolts when you put it in. Dont want them backing out on you = crappy day.

The transfer case shouldn't weigh more than 70 to 80lbs. "passenger seat for the win" set it on a towel and seat belt that bad boy in for safety. Trans. Ya gotta roll under the hatch for that. Bring some tie down bungy or straps to secure it, and to hold your hatch down just in case you have to leave the tail hanging out. "tie a shop towel on it so it will be marked for cars behind you to see more easily". Other than that, I cant really think of a whole lot of other things you need to change or mess with. Hope you get your pathy back on her feet.

 

Best of luck to you \

 

Pat

[oaky8]

Thanks for the replies!

 

I got the whole junkyard tranny and transfer case home in my dads sedan. Im a small dude and manhandling the transmission+transfercase by myself really took me out. I had a long nap once i got home.

 

I think the transmission cooked itself because I didn't take care of it then towed. The pathy wasn't driven regularly for about 6 months in 2014, my dad would take it for a spin every once in a while for me. Once I got back home and began driving it daily again I noticed the hard shift from 1 to 2nd gear. I should've flushed the fluid then, but i didnt. lator on coming into 2015 i towed a utility trailer with about 700lbs of stuff about 750 miles (LA to FL), during the drive i felt a lot of heat coming from e-brake handle area. Didn't really cross my mind that it was overheating. I think the dash has an A/T overheat idiot light, it never came on. The transmission drove fine and never slipped until what i described in first post "trannys dropped 4th then re-engaged 4th. So quickly that it almost felt like a bump in the highway". So cause of failure being old fluid that was past due for a flush, probably full of metal and not very good at handling heat anymore.

 

I haven't had a chance to drop current transmission. But i'm thinking i will take both torque converters to a shop and have them tested. I think the one way stator is making the noise during idle. If Its just the torque converter i will use the current transmission because im sure its lower millage. I will then have the transmission gone through and made sure its clean and free of debris. Also it seems like the salvage transfer case leaked/s fluid. So i will likely take back the transmission and transfer case but use the torque converter. I will definitely clean out the radiator and fluid lines.

I'm also thinking to relocate the breather hoses higher up, they are way too low and pointed down. The few times i've been through some mud puddles or in a small creek i got mud and water on everything in the engine bay.

 

[Procrastinational]

I read that the gears are shorter on the manual. I would really like for the pathfinder to be able to cruise at 80mph without having to be at 3K rpm. Is there any other gear set i can swap in or should i just look at doing a rear end final drive swap? I hardly use the 4wd or go off road so i don't especially need short/low gears. I would rather highspeed highway cruising.

That's the one thing I hate about my 5-speed. RPM's are very high on the highway. Mine hovers around 3500 at 80.

Mind you, it'll run at that all day long if you can put up with the noise, but it's very tiring on road trips.

 

For your use it sounds like replacing with an auto is the right choice.

Edited February 28, 2015 by Procrastinational

[fixinto]

Ya we can crawl up a tree with the SE five speed but as far as interstate goes. 70mph 3200rpm. i usually drive 58ish. its 2500ish. better gas millage.

 

 

pat