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Discussion Starter · #1 ·
Man...has this truck been a disaster or what?

I bought a 2006 Frontier V6 4x4 with 95k miles on it in the summer of 2016. I discovered bad transmission fluid shortly after the purchase, so I swapped out the fluids and bypassed the factory cooler but it was too late: in November 2016 the transmission failed. A local shop with a good reputation did the rebuild. When I got the truck back, it had a kind of subtle shudder sometimes during the 2-3 shift. But I drove it thinking maybe the problem was in my head.

Three weeks later, the Service Engine Soon light came on (cat codes on both sides), and a week after that the truck suddenly lost power. The engine wouldn't rev beyond 3000rpm, anything above 1500 sounded like the engine was coming apart, and 20mph was the top speed. Having just paid $3500 for a tranny rebuild, I didn't want to even think about having to replace the engine. I'd never heard of bad cats taking out an engine, and it seemed really odd that factory cats would go bad at only 95k miles.

After a few weeks, I decided to go under the truck and remove the cats. When I did, I saw shiny dents on the exhaust system. Turns out the transmission shop beat on the exhaust hard enough to dent it when they removed the crossover pipe. When I removed the forward cats, one of them was just a shell: all of the ceramic and insulation had blown downstream into the second cat, completely blocking it. The ceramic matrix had turned to powder. The other side had started coming apart, but most of the matrix was still in place. With the primary cats removed, I started the engine and--lo and behold--the engine sounded fine!

So I ordered new cats and installed them. I also did a compression check. The driver's side bank were all around 150psi. The rear passenger side cylinder was 200psi, but the center cylinder was 120psi! That was on the side that had the empty cat that had completely destroyed itself. I thought maybe ceramic particles were hanging up in the valves and causing the low compression. So I cleared the codes and fired up the engine...it sounded fine. I was tempted to call the shop and make a claim about the broken cats, since it appeared them beating on the exhaust may have fractured the ceramic matrix, leading to catastrophic failure after a few weeks of driving. But instead I just kept driving the truck. Within a week, compression on all cylinders was 195~200psi. I figured whatever was causing the low compression had resolved itself. Turns out that was wishful thinking.

After 1,200 miles or so, I noticed that the oil pressure gauge was dropping low when I went around corners. I checked the oil level and--HOLY COW!!--the dipstick was dry! I topped off the oil, thinking I must have messed up the last time I'd changed the oil. 1,000 miles later, the same thing happened. I topped up again. This time I called the transmission shop and stated my claim. I sent them pix of the dented exhaust, the cat matrix that turned to powder, the low compression, and now the oil consumption problem. I also told them about the harsh shifting problem. They told me to bring it by.

After topping off the oil, they said bring it back in 1000 miles. 700 miles later, the oil was down past the Add mark, so I brought it in. They agreed that the oil must be passing either the rings or the valve stems, but they wouldn't take responsibility. They also said they didn't feel the harsh shifting. So they told me to take it to the dealer for an assessment and report back.

The dealer did an "oil consumption test," which means they topped up the oil and sent me down the road. 700 miles later, I went back. Same problem. The dealer did note the harsh shift. Their assessment stated that they don't recommend rebuilding these transmissions. They only replace them with remanufactured ones, which have a lot more stuff replaced and checked than your average rebuild. So, it need a reman transmission AND an engine long block AND new cats because the new ones I'd just installed were oil fouled by the several gallons of oil that had gone through them in just a few thousand miles. The total estimate was $16,000.

I brought it to the transmission shop and, to my surprise and after some haggling, they agreed to replace the engine, cats, and to dig deeper into the transmission Three weeks later, I got my truck back. The engine seemed fine, but the 2-3 shift was still harsh. I brought it back immediately. They took it apart again and replaced a carrier something something...but again, the 2-3 shift was harsh. But while I was driving home, the engine stumbled at the SES light came on. There were powertrain codes and a pending crankshaft position sensor circuit A code. I limped the truck back to the shop.

After a bit of searching online, I found some transmission rebuild industry group websites that had articles talking about rough 2-3 shifts on the Nissan RE5R05A transmission. Here's one of them: http://www.atra.com/Gears/2011/2011-04/2011_4_4.pdf
I forwarded that article to the shop, and they said they'd look into it. They also reported that the engine problem was caused by a broken tooth on the flywheel/flexplate. A week later, when I got the truck back, they said they'd replaced the flywheel with a good used one and torn the transmission apart and replaced the o-ring mentioned in the article with the preferred upgraded one. I drove away and--FINALLY!--I think the shifting problem is solved.

But before I got home 70 miles down the road (where the roads are smooth and rough shifts become very apparent), the engine stumbled again, the SES light came on, the engine is in limp home mode, and it's throwing that pending crankshaft position sensor circuit A code again!

I dropped the truck off at the repair shop two weeks ago. The code went from pending to fail on the way to the shop. The shop has reported that once again, the flywheel has a broken tooth that's throwing off the crankshaft position sensor. They're replacing the flywheel with a brand new, OE one. I hope to finally get the truck back today.

Has anybody ever had broken teeth on a flywheel that seem to break while driving? This is just nuts. And to think: all of this started when some beancounter at Nissan HQ decided to cheap out to save a few dozen yen on the transmission cooler in the radiator...

If anybody has any thoughts or suggestions, I'm all ears.

Thx
Q
 

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Discussion Starter · #4 ·
The rebuild was $3250. Towing included. Two year warranty. Of which, I've got 9 months left. And based on the drive home today, it's finally fixed.

I wasn't sure what the guy meant when he said a tooth on the flexplate was broken. I thought he meant a starter ring tooth. But I picked up the truck and saw the old parts. As you can see in the pix below, two of the crankshaft position trigger tabs/teeth are bent and there was obvious contact with something. The third tooth (furthest left) was knocked off clean. I couldn't get a good planar shot, but the two tabs that had been hit were out of plane with the other tabs around the circumference of the flexplate. Not by much and, oddly, one is bent toward the engine side and the other is toward the tranny side.

The dude said there was a bit of aluminum sticking out from the housing and was somehow interfering with those tabs. He said they took a die grinder to it to give it more clearance. This used engine reportedly has 95k miles on it, and it feels like the truck used to when I first bought it--plenty of scoot. So I have no idea how anything in the rotating assembly could be so loose as to move many thousandths of an inch such that the flexplate tabs would contact metal in the housing.

There's no sign of contact on any of the other 27 tabs around the plate. The only thing that comes to mind is that the first one came with the used engine, and the wrecking yard tweaked them when they pulled, stored, or shipped the engine. The second time, the transmission shop bought a used flexplate. So it could have had the same rough treatment. The one they installed this time is new, pristine, and came out of a Nissan-branded box. Problem solved? Time will tell.



 

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Discussion Starter · #6 ·
That's good to know. The last time it happened, I turned onto a 50mph country road with traffic approaching. I romped on it hard enough to git up and go but not enough to light up the tires. And that's when the stumbling started. If that whomp of Nissan brute force changed the relative position of the tranny and engine by just a bit in the absence of the pin, I could see how contact would happen.

Now the question is: do I romp on it the same way tomorrow and test the theory, or ask the shop if they remember whether or not the pins were in place?
 

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Discussion Starter · #8 ·
Heh. That's true.

Problem is, the shop is deep in the...how shall I put it...multicultural part of an urban sh1thole, where melanin-challenged people like me are generally not welcome. The shop owners seem to be straight shooters, but I hate going there because of the...local environment. And I've been back 17 times (9 times to pick the truck off, 8 times dropping it off).

Then again, either way, if it's missing a dowel, it's gotta go back either way and they're not giving me free towing anymore.

That's it! Tomorrow...I romp! Stay tuned...
 

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Seems like that shop is not that good, for you to be there that many times.
 

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The rebuild was $3250. Towing included. Two year warranty. Of which, I've got 9 months left. And based on the drive home today, it's finally fixed.

I wasn't sure what the guy meant when he said a tooth on the flexplate was broken. I thought he meant a starter ring tooth. But I picked up the truck and saw the old parts. As you can see in the pix below, two of the crankshaft position trigger tabs/teeth are bent and there was obvious contact with something. The third tooth (furthest left) was knocked off clean. I couldn't get a good planar shot, but the two tabs that had been hit were out of plane with the other tabs around the circumference of the flexplate. Not by much and, oddly, one is bent toward the engine side and the other is toward the tranny side.

The dude said there was a bit of aluminum sticking out from the housing and was somehow interfering with those tabs. He said they took a die grinder to it to give it more clearance. This used engine reportedly has 95k miles on it, and it feels like the truck used to when I first bought it--plenty of scoot. So I have no idea how anything in the rotating assembly could be so loose as to move many thousandths of an inch such that the flexplate tabs would contact metal in the housing.

There's no sign of contact on any of the other 27 tabs around the plate. The only thing that comes to mind is that the first one came with the used engine, and the wrecking yard tweaked them when they pulled, stored, or shipped the engine. The second time, the transmission shop bought a used flexplate. So it could have had the same rough treatment. The one they installed this time is new, pristine, and came out of a Nissan-branded box. Problem solved? Time will tell.



I recently got my tranny serviced because of SMOD and now I am having the same exact issue with my flywheel/flexplate. I called the shop about this and they said if it's the starter or the flywheel, then it is not covered under the Tranny warranty. What should I do? Could the starter contact these crankshaft position tabs in any way?? I heard a whirring sound, I heard some grinding, and I even heard the grinding while I was driving. Haven't driven it since. This happened two days ago. Should I let the shop send a tow truck for it? Should I change the starter? I'm at a loss here. Spit-balling ideas here, could they have not aligned the tranny onto the motor correctly. The service was done 4K miles ago. Could the starter have loosened up and misaligned itself? Why now? This happened during a cold start. I live in Houston, TX, there is no extreme cold to worry about. When I turned it on last night, I heard a revolving clatter sound that went with the RPM. I bet the shop will chock it up to wear and tear and out of their hands. I'm sure they'll say, we'll cover the tow if you pay for the fix. Being that this is the fly wheel tabs that are damaged, they may try to say that if i don't change it out, it will void my warranty on the transmission since it will throw off the balance? Could this throw it off balance?

Asking for Ideas and opinions. Help a brother out.

07 SE 4x4 146K miles
 

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Discussion Starter · #11 ·
Man...that sucks.

My truck's been awesome since I got it back last. I can't tell you as a matter of fact whether it was, as V8 man diagnosed, one of the locating pins was missing, or if it was some aluminum casting material sticking out too far and needed grinding off, which is what the shop claimed (but seems extremely unlikely). If V8 man's diagnosis was accurate, then your rebuild shop lost a locating pin while they had the engine and tranny separated. I have little doubt that V8 man's diagnosis was faulty, and the shop made up the story about aluminum casting material needing to be removed. I mean, c'mon...we're talking about Nissan not some Soviet or Red China manufacturer. It's not like they'll have linemen grinding off chunks of excess engine casting material as the vehicles are being assembled.

If you take it back to them for repairs, be there as they do the work. When you see the transmission come down, stroll out into the shop and lay eyes on it. They probably won't want to acknowledge their screw up.

Keep us posted how it turns out.
 
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