I have read a few posts on this subject but went ahead and asking a question. Last Friday I took my 2017 Wrangler JKU Rubi HR to the transmission shop for a fluid change. They pulled the P7031Code before starting any work. Called me and warned my transmission clutches are more that likely damaged. I just added bigger tires 35 Nitto Ridge Grapplers and changed the gearing from 3.73 to 4.56. Gear change I updated the OBDC with JSCAN to 4.56 before they started but they had to pull it in bay with the 3.73 gear before the physical change took place. I forgot my programmer and I drove home on the 35's while my programming was off on the wrong tire size. Anyway my assumption is the tire and gear change caused the code. We cleared the code at the transmission shop and I am driving it for a few days to see if it will reset before proceeding. Anyway this shop is telling me if there is clutch material in the pan when they pull it I will need to get a $4000 rebuild. Does this make sense is there not a better way to just repair a part and not rebuild the entire transmission?

 

I'd imagine if you changed the gear ratio and then even just pulled it into the bay with the mismatched gears to what the ECU knows, that would be enough to throw the code. The tire size really has nothing to do with it. The tire size will make your speedo and shift points off, but you can drive forever like that and not throw any code. I wouldn't stress too much about this myself. Some fearmongering by the shop IMO.

Changing the tranny fluid isn't a hard DIY should you consider it. A mittyvac sucks most of the fluid out the dipstick tube, remove the pan, swap the filter, reinstall the pan and add new fluid (the same amount you removed). Not too bad, and you have mittvac for future use....all for way cheaper than shop is going to charge . I do get some folks don't, or can't, DIY....so just throwing the idea out there.

 

I appreciate the advice and comment on the code. I wasn't sure if it would be the tires or the gearing or both. For changing it your self I have read that the frame is a pain to get around with the pan. I should have most all of the tools here and could pull it up on a set of ramps. If that is not that big of a problem it is something that I would one interested in doing myself. Interesting this tranny shop earlier this year, I have a 2013 Lexus ES350 with a 6 speed tranny. The transmission started slipping when it was cold just for the first shift or two. I took it to them and they looked at it and said $5300 to fix and I about fell down..... Thought about it and if the car is broken its worth nothing and at 140k miles it is worth something more than that running. So I bit the bullet and paid them. It took them 2 months to finally get it right it continued to slip when cold and now had a growling hydro noise only in reverse.. In the end it was a plunger seal that they did not replace in the rebuild kit.... So with that said I do think they are a good shop been there a long time. So i was going to let them change the fluid in the Jeep easy right. Then they pointed to the dreaded P7031 Code and more drama. Thinking about it I wonder why the plunger seal was not replaced in the initial rebuild maybe it is not part of a standard rebuild kit. Then to see them again with the Jeep code and $4000 for a rebuild really got me nervous.

 

Well, i'm not going to lie, the two rear-most bolts are right over the exhaust and the cross-member. They can be a pain to access, but for me the secret has been using a small bit driver like this with the appropriate torx bit -



My exhaust has been rerouted so it's not in the way.....but my buddy recently did this service and his exhaust is still there and did not have an issue after sucking as much fluid as possible out through the dipstick tube. If you don't do that then well, it's a complete mess with tranny fluid spilling all over. My first service I attempted a "controlled spill". I'd stress "ATTEMPTED"! Also, if you use mittyvac to pull the fluid out you have an easy measurement of how much fluid to put back in. We typically just do a simple drain/refill with a filter change.