[JerseyHarold]

The vehicle is my 2014 Patriot with 2.4 engine, 6-speed automatic, and 4WD, with a little more than 100K miles.
Several months ago, it developed an under-floor thunking when accelerating or turning. It's somewhat intermittent but definitely present.
After replacing all 4 CV axles the noise is still there. I took it to another shop for diagnosis-only and they said it's a loose inner CV joint on the left front half shaft. I sent the Patriot back to the shop that did that repair originally, and they said the CV axle is OK, but the output shaft of the transmission is loose and I should take it to a trans shop.
My questions are:
Has anyone had experience with a concern like this? Can something else be at fault?
Can this be repaired without a full rebuild (in my experience, transmission shops LOVE to sell a complete rebuild as a cure-all for any concern)?
Any ballpark idea of what such a repair would cost?

Thanks in advance for your thoughts or advice.

Harold

 

[todde702]

That output for the rear drive shaft is actually out of the PTU or power takeoff unit. It unbolts from the transmission. Many people neglect the gear oil change on it and the rear diff, being an every 60k mile interval so the output bearing could be bad.

 

[JerseyHarold]

That output for the rear drive shaft is actually out of the PTU or power takeoff unit. It unbolts from the transmission. Many people neglect the gear oil change on it and the rear diff, being an every 60k mile interval so the output bearing could be bad.

Thanks for your reply. The left front CV axle is the one that's loose at the PTU.
I forgot to mention that when you go from drive to reverse there is a loud clunk from under the floor, and a squeaking noise when backing up. I got under the rear of the Jeep a while back and there is play at the RDU if you rotate the driveshaft. I don't know how much is too much or if it's related to the looseness at the front axle.

 

[todde702]

Well the PTU is only on the right side of the CVT and it spines directly into the differential carrier in the CVT. The right side CV shaft is very long, goes completely through the PTU and splines into the spider gears in the CVT differential. The left side CV axle goes into the other side spider gears of the CVT differential. So the way the Patriot 4x4 system works, as long as one front wheel is spinning, power can be transmitted through the PTU and to the rear diff. That said, we did have a person on here recently report they had their CV axles replaced, and the replacement was a little short and would not seat fully into the CVT to engage it's lock ring. Here's that thread, maybe your initial noise was a bad CV, but the new, similar noise is a length issue?
CV Axle vibrations lately | Jeep Patriot Forums

 

[Sandstone]

when you go from drive to reverse there is a loud clunk from under the floor, and a squeaking noise when backing up.

Almost sounds like a bad u-joint...

 

[JerseyHarold]

Thanks for the ideas. The place that did the front CV axles said the looseness they found was not the axle but is in the RDU itself. From the previous discussion and links, it looks to me like if there was an internal issue with the RDU there would be more noise and vibration than I'm getting...you'd think it would blow itself apart. I'm leaning towards the axle being too short to fully engage the lock ring. Maybe I should try to get the part number the shop used and see if the axle manufacturer/rebuilder has a reputation for short axles.

What's frustrating is that I haven't personally been under the Patriot to see things for myself. I'm a car person but this is the first 4X4 I've owned, and shops don't want you to go under the vehicle on their lift.

 

[JerseyHarold]

Correction: I meant to say Power Transfer Unit, not RDU.

 

[Sandstone]

JMO, but if the original problem developed before you had the axles replaced, then to me it's less likely to do with the replacement axles being the wrong length.

I know this isn't the best example (totally different vehicle), but in this case there's squeaking under power only in reverse, turns out to a drive shaft u-joint (around 9:50 in the video)

If you have someone who can help, you might have them operate the shifter back and forth from reverse to drive and back with their foot on the brake while you (carefully) look under to see if you can better tell where the clunk is coming from.

 

[JerseyHarold]

JMO, but if the original problem developed before you had the axles replaced, then to me it's less likely to do with the replacement axles being the wrong length.

I know this isn't the best example (totally different vehicle), but in this case there's squeaking under power only in reverse, turns out to a drive shaft u-joint (around 9:50 in the video)

If you have someone who can help, you might have them operate the shifter back and forth from reverse to drive and back with their foot on the brake while you (carefully) look under to see if you can better tell where the clunk is coming from.

I'm pretty much a one-man band and wouldn't be comfortable being underneath the Jeep while someone goes through the gears. I considered the driveshaft as well. Is the rear u-joint replaceable or do I need a whole driveshaft? I found a manufacturer and part number for the center carrier bearing, FWIW.

 

[mr_et2]

If you've got a go-pro or similar camera, set that up underneath while you shift thru the gears.

 

[Sandstone]

Is the rear u-joint replaceable or do I need a whole driveshaft?

U-joints are on ebay, I think NAPA and other places sell them too, but they're probably all made somewhere else.

Fits - Jeep Patriot 2007-2014 - Driveshaft Ujoint Pair ( 2 U-joint ) | eBay

Jeep Patriot 2007-2014. No Modifications, No Welding, and No Special Tools Required.

www.ebay.com

If possible, I'd try to get one with a grease fitting.

 

[JerseyHarold]

I went back to the shop that did the inspection and he is adamant that the trans is OK. I then circled around to the shop that did the work and asked them for the they said they couldn't find the part number of the left front axle they installed. I explained I had done some research and found some axles are a little short and don't fit well. They came up with GSP NCV12600. Depending on the reference, some parts listings show it as a left rear axle and others as a left front. I tried going to the local Jeep dealer with my VIN, but they were closed today. I want to pin down exactly what the Mopar parts number is and then I can cross-reference to aftermarket numbers. I asked the shop owner to put the Jeep on a lift to see if there is an aftermarket number on the axle. This should happen late this week or early next.
I'm trying to do anything I can to avoid involving a transmission shop because they are 'rebuild only' operations and aren't ashamed to ask big (and often outrageous)bucks for any job they do.

The other reason I don't want a trans shop involved is because once they touch it, the first shop's responsibility evaporates.

Sorry for the rambling but I'm pretty frustrated at this point.

 

[Sandstone]

No worries, thanks for the update.

 

[JerseyHarold]

I went to my local Jeep dealer, less than two miles from home, to get the factory part number of the left front CV axle. My plan was to cross reference the aftermarket number from it. I was amazed when the parts guys told me: We don't give part numbers because then customers can use them to compare prices. I asked for the parts manager and was told the same thing. Guess I'll have to try another dealer and see if they will help. It sure is a strange way to do business....

 

[todde702]

There are quite a few online oem parts lookup sites that give you all the oem part numbers. Such as: 2007-2017 Mopar Axle Half Shaft, Left 5085220AE | Mopar Estores

 

[JerseyHarold]

There are quite a few online oem parts lookup sites that give you all the oem part numbers. Such as: 2007-2017 Mopar Axle Half Shaft, Left 5085220AE | Mopar Estores

Thanks for the link. There's more than one possibility when it comes to the axle part number, which the shop had trouble pinning down. My idea was to ask the dealer for the part number used in my particular Patriot by VIN. I'm concerned they used the wrong part.

 

[Sandstone]

FWIW, here's the link for Mopar's online parts catalog, which is supposed to be able to give you the right part number according to VIN.

MOPAR Online Parts Catalog

ShowMeTheParts is changing how the world finds replacement parts for their vehicles.

catalog.moparrepairconnect.com

 

[JerseyHarold]

Looks good, thanks for posting the link. I'll check it out later after work.

 

[JerseyHarold]

UPDATE: I got the Mopar part number for the driver's side CV axle and crossed it over to a GSP number (GSP is the aftermarket axle manufacturer). I brought the Patriot in to the shop yesterday and the part they installed has the correct number. They replaced the driver's side axle under warranty but it still shakes where the inner axle goes into the transfer case. They ran the Jeep on a lift and the shake is obvious. I also noticed a slight shake in the passenger's side axle, but it's nowhere near as pronounced as the driver's side.
I assume there is a bearing in the transfer case that has gone bad. Can anyone name that part so I know what I'm asking about? Can the bearing be replaced without dropping the transfer case and/or transmission? Any idea of cost/labor time involved? Would a drive-line shop be a good choice to try? I live in Freehold, New Jersey 07728 (Jersey Shore area) if anyone has a recommendation.

Sorry for the long post. I appreciate everyone's help.

 

[Sandstone]

They replaced the driver's side axle under warranty but it still shakes where the inner axle goes into the transfer case....

On the drivers side, the axle goes into the transmission directly.
Judging by the way the transmission is put together, it would have to be removed and the case split to get to whatever is worn or loose.