Lost reverse but other gears are fine (Urgent Help Please!)

[Xander386]

So for context, about a month and a half ago I started towing trailers with small-medium loads on my 270k mile RWD 2002 QX4. And ever since I started towing more things have gone down hill. It started with it not shifting out at highway speeds. So I did a transmission fluid flush and it fixed that issue (the fluid was healthy and there were no metal shavings or "glitter" in the fluid). Then a few days later I hop in my car to go somewhere. Thinking my transmission was fine, as it was the day before (shifting perfect feeling healthy, driving smoothly). And it wouldn't engage reverse. It took some time, but I did get it to engage the gear, but I had to actually let the engine warm up for about 5 minutes with some light revving before it would do anything but act like neutral. Which after some research led me to believe it could be whats called a Line Pressure Solenoid (LPS). But after calling some transmission shops ive also gotten the opinion that it could be a "Reverse clutch drum" or something similarly named. I have a few options that I'm considering. But, because these things never happen at a great time. I'm tight on money and really cant afford a whole new transmission and installation costs. Not to mention how I need this car being able to tow, in order to continue making money. I really just want some opinions out of this. And if you or someone you know has had to deal with this issue I'd love some insight.

Solution 1 - pull a part transmission. On their site it says transmissions from pull a part locations average an $85 price tag. Very very manageable. Seeming like my best option at the moment assuming i can win a coin toss and get a working healthy one.

Solution 2 - I go on rockauto and purchase a shift solenoid. There are two listed, so it has me confused on which . As they are both listed as shift solenoids on rockauto. (Solenoid one, and solenoid two). They are $150 each. And finally buy a pressure control solenoid ($200) (which i guess would be the LPS i saw someone refer to in another "i lost reverse on my pathfinder" thread. As well as a 'shift improvement/reprogramming kit' ($350 from the right distributor) which would increase tow capacity and such. The only problem with this is that I would have to do this myself, or pay lots in labor at a shop. Avoiding shops this would cost around $700 all in including some tools i lack. Not to mention how ive never dug inside a transmission before.

Solution 3 - (this is if all else fails) eat the damage and buy a new/re manufactured transmission from a local distributor or shop and have it installed. This would end up around $2,000-$4,000 if my estimates are right. Again, this is my last resort.

And solution 4 - This is combining options one and two. Junk yard transmission WITH the shift improvement kit. $85 (transmission) + the $350 (kit). $435 inparts. And then possibly labor fees if i decide to not risk messing up my transmission with my own shoddy work.

IDEALLY i could get option 4 for relatively cheap because that improvement kit would be a life saver for towing. The last place I want to be in is this situation again in the future.
But yeah every gear is fine. They all shift and engage amazingly.... except reverse. It just acts like neutral until the engine is warm. Then it will engage pretty reliably but no sooner. This only started in the last 2 or so weeks for the most part.

Any and all insight is appreciated! Thanks in advance.

[Aznpersausion]

1 hour ago, Xander386 said:

 I'm tight on money and really cant afford a whole new transmission and installation costs. Not to mention how I need this car being able to tow, in order to continue making money. I really just want some opinions out of this.

 

I just saw you previously posted that you upgraded your rear shocks to the more expensive bilsteins for no good reason. You were even looking into OME struts...crazy. That money you could have saved with the 5100s could have been used for a rainy day such as today. My opinion is you need to get smart with your money.

 

With that said, your transmission is almost certainly done. Have you properly checked the fluid level? Here is the FSM:

 

https://www.nicoclub.com/infiniti-service-manuals

 

Edited August 1, 2023 by Aznpersausion

[Xander386]

I understand what you're saying but realistically those purchases had no affect on this now. Some events happened in mine and my families lives that i would rather not have to explain on a car forum. But, thanks for your courtesy...

And I understand that its probably cooked. Which is why I was listing my options for replacement transmissions. And yes, I did in fact check my fluid level properly. I did a full fluid flush and filter replacement. And put back in the proper amount of fluid. And as I explained, it did no good for reverse after a while. For about 5 days it drove perfectly, then the reverse issue came back out of the blue.

[hawairish]

10 hours ago, Aznpersausion said:

I just saw you previously posted that you upgraded your rear shocks to the more expensive bilsteins for no good reason. You were even looking into OME struts...crazy. That money you could have saved with the 5100s could have been used for a rainy day such as today. My opinion is you need to get smart with your money.

 

My opinion is this should have been omitted.  It's none of your business how, when, or on what people spend their money on.  Shaming them about it is bull@!*%.

 

12 hours ago, Xander386 said:

I really just want some opinions out of this.

 

Haven't experienced this, and hope not to, but the issue has surfaced here in the past a few times.

 

My opinion would be either option 1 (pull-a-part transmission) or option 3 (get it repaired professionally).  Option 2 is largely throwing parts at a problem, but for all you know, option 3 could become option 2 if the shop says one of those parts is the problem and can change it without a full rebuild.  Problem is option 2 may only be delaying an inevitable failure, and then you're right back at the beginning.

 

If you think you can rebuild yours, but you need the truck operational to bring in income, then go with option 1 and try to limp along.  This would give you time to rebuild the transmission, either by yourself or professionally.  Swapping the transmission isn't terrible, provided you have a bunch of extensions, some patience, and a transmission jack.  There may also be a lot in savings if you pull it yourself and still have it professionally rebuilt.

 

Of course, if you're mechanically inclined and just happen to have an extra transmission to play with (after taking option 1), you might as well explore.

[Slartibartfast]

First thing I'd do is check that the fluid level is correct. Auto trans fluid levels can be tricky to get right. I doubt this is the problem unless yours has a leak somewhere, but, yeah, worth checking the easiest thing first.

 

Given how fun transmissions aren't to remove, I would be tempted to drop the pan and check the solenoids that you suspect are bad first, on the off chance you find something obviously wrong. If you find a smoking gun, order some parts and see if you get lucky.

 

That said, $85 for a used/lower mileage trans sounds pretty good compared to $350 for solenoids that may or may not buy you some time on a box with 270k on it. And then, yeah, you could have your old one gone through, or dig into it yourself at your convenience, so you're not rebuilding your first transmission in a panic with the truck on jackstands.

 

Either way, the AT section of the service manual should come in handy, if you haven't downloaded that yet.

 

When I flushed mine, I added an external cooler and a Magnefine external filter in hopes of keeping it going longer. The cooler especially is a good idea if you're towing frequently.

 

1 hour ago, hawairish said:

Shaming them about it is bull@!*%.

 

Agreed.

Edited August 1, 2023 by Slartibartfast