Installed 4.56 gears on an auto 2017 and blew all the seals!
03-18-2021, 11:14 AM
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Installed 4.56 gears on an auto 2017 and blew all the seals!
I had a shop install the 4.56 gears and a few weeks later my wife is driving down the road and all the seals blow out. The shop inspected the gears afterwards and said they were just "too big" a other friend of mine agreed, however all the research I've found says 35s with 4.56 is the perfect crossover between daily driving and offroad. A few more facts.
- she was on the highway doing 60ish at 2700 -3k (not in o/d)
- the shop put a different gear oil in than extreme terrain said should be used which is 85/140
- I'm 8000 miles away on deployment and have no idea how to help her😂
- she was on the highway doing 60ish at 2700 -3k (not in o/d)
- the shop put a different gear oil in than extreme terrain said should be used which is 85/140
- I'm 8000 miles away on deployment and have no idea how to help her😂
03-18-2021, 11:39 AM
#2
Super Moderator
Which seals did it blow? 4.56 isn't too much gear, I've got it and run 70mph every day on 35's. I installed it myself at that. Gear oil is going to be negligible in my opinion. Should they have a good gear oil, sure, but really- and oil is better than none. I run 85w-140 but have mixed in 75w-90 in a pinch.
03-18-2021, 11:48 AM
#3
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Welcome Jerry68.. Thanks for your service.. Which axle.. Front or Rear? NOW.. the shop that did the install should "man-up" as something is not installed correctly.. Seals just don't Blow OUT.. I see you have a 2017 Sport.. it should have a Dana 30 Front and 44 rear.. the Dana 30 will not handle 4.56 gears WITHOUT Changing the Differential CARRIER. If your Friend is in Jacksonville have them check all the receipts for everything; find out why the shop failed to follow the instructions on gear oil and also ask the friend to visually inspect for gear oil leakage.
JKF members in the Jacksonville Fl area - your help would be great or at least a referral to a Good Shop.
JKF members in the Jacksonville Fl area - your help would be great or at least a referral to a Good Shop.
03-18-2021, 11:49 AM
#4
JK Freak
My first thought would be plugged vent or kinked vent hose, size of gears doesn’t matter
03-18-2021, 12:08 PM
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Which seals did it blow? 4.56 isn't too much gear, I've got it and run 70mph every day on 35's. I installed it myself at that. Gear oil is going to be negligible in my opinion. Should they have a good gear oil, sure, but really- and oil is better than none. I run 85w-140 but have mixed in 75w-90 in a pinch.
Also more of a shade tree mechanic and I'm always learning so I apologize if I dont use the proper terminology.
both front and rear axles and the seals around the axle shafts to clarify further.
thanks for the help gents
Last edited by Jerry68; 03-18-2021 at 12:11 PM.
03-18-2021, 01:06 PM
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Welcome Jerry68.. Thanks for your service.. Which axle.. Front or Rear? NOW.. the shop that did the install should "man-up" as something is not installed correctly.. Seals just don't Blow OUT.. I see you have a 2017 Sport.. it should have a Dana 30 Front and 44 rear.. the Dana 30 will not handle 4.56 gears WITHOUT Changing the Differential CARRIER. If your Friend is in Jacksonville have them check all the receipts for everything; find out why the shop failed to follow the instructions on gear oil and also ask the friend to visually inspect for gear oil leakage.
JKF members in the Jacksonville Fl area - your help would be great or at least a referral to a Good Shop.
JKF members in the Jacksonville Fl area - your help would be great or at least a referral to a Good Shop.
03-18-2021, 02:27 PM
#7
Super Moderator
The rear axle seals usually are reinstalled without issue as they sit out on the ends of the axle shafts. They're easy to damage though. Your indicator would be wet brake backing plates- if you knew what to look for, most people in general don't or won't. The front axle is similar except the seals are closer to the center section. Your gear set most likely came with new seals and on a 2017, I wouldn't have changed to the included seals either as they are inferior to what the vehicle came with. Again- the axle shafts have to be reinstalled carefully otherwise it's easy to tear the seal....ask me how I know.
That being said- shade tree or not, the fault happened as a result of reinstallation. It should have been noticed by the operator but it's easy to overlook those as residual oil from the install. Usually you'll get a 500 mile break in and then you've got to change the fluid. At that point, he should have noticed it and mentioned that it needed more work.
Regarding the gear set on your differential carrier- that change is only necessary (to a different carrier) if the vehicle originally had the 3.21 gears. Mine did not so I was able to reuse both front and rear carriers.
Side bar- axle seals are cheap, labor to do them is not. They're just labor intensive to get to them, though not difficult.
That being said- shade tree or not, the fault happened as a result of reinstallation. It should have been noticed by the operator but it's easy to overlook those as residual oil from the install. Usually you'll get a 500 mile break in and then you've got to change the fluid. At that point, he should have noticed it and mentioned that it needed more work.
Regarding the gear set on your differential carrier- that change is only necessary (to a different carrier) if the vehicle originally had the 3.21 gears. Mine did not so I was able to reuse both front and rear carriers.
Side bar- axle seals are cheap, labor to do them is not. They're just labor intensive to get to them, though not difficult.
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03-18-2021, 05:59 PM
#9
JK Jedi
I don't think I've ever multi-quoted so many in one post.
This is just total bulsh. Anyone telling you that 4.56 are "too big" have no clue what they are talking about. If they mean geared too low, that is a bunch of crap. If they mean "too big" as in they needed a different carrier, the ring gear literally wouldn't have bolted up to the old carrier. You could run that jeep with 5.38 gears which is as low as you could go, not adviseable with 35s, but even then you're not going to blow all the seals out, you'd just run really high RPMs.
I'd agree that the different weight of gear oil was not the difference maker here.
+1, as noted, the 4.56 gears literally wouldn't fit without the proper carrier. The ring gear bolts would not line up.
+1 here that the axle isn't being vented properly, and/or also likely they jammed the front shafts in carelessly and knicked the seals in the process. Anyone charging people to regear should know better though.
Literally no way to do a regear without pulling, and mangling, the pinion seals so those had to be replaced which I think is what you're getting at here. The front seals SHOULD have been replaced regardless. It's literally like 5 mins cuz everything is out anyhow. The rear seals do not get replaced during a normal regear (as Karl notes later).
The gears are chewed up cuz you lost that much gear oil and they weren't getting lubed, or cuz they eff'd up the regear in general? I mean, kinda sounds like they didn't have the pinion preload correct which lead to quick failure of the pinion seals. This could have lead to a lot more heat in general and failed axle shaft seals too I guess.
+1 on everything Karl said here and what I probably already reiterated above.
In general, it sounds like a real crap situation unfortunately. It sounds like maybe you purchased the parts and took them to the shop? If so, this is the reason you always let the shop purchase the parts too. That way regardless of part failure or install error, it's all out of your hands.
Which seals did it blow? 4.56 isn't too much gear, I've got it and run 70mph every day on 35's. I installed it myself at that. Gear oil is going to be negligible in my opinion. Should they have a good gear oil, sure, but really- and oil is better than none. I run 85w-140 but have mixed in 75w-90 in a pinch.
The rear axle seals usually are reinstalled without issue as they sit out on the ends of the axle shafts. They're easy to damage though. Your indicator would be wet brake backing plates- if you knew what to look for, most people in general don't or won't. The front axle is similar except the seals are closer to the center section. Your gear set most likely came with new seals and on a 2017, I wouldn't have changed to the included seals either as they are inferior to what the vehicle came with. Again- the axle shafts have to be reinstalled carefully otherwise it's easy to tear the seal....ask me how I know.
That being said- shade tree or not, the fault happened as a result of reinstallation. It should have been noticed by the operator but it's easy to overlook those as residual oil from the install. Usually you'll get a 500 mile break in and then you've got to change the fluid. At that point, he should have noticed it and mentioned that it needed more work.
Regarding the gear set on your differential carrier- that change is only necessary (to a different carrier) if the vehicle originally had the 3.21 gears. Mine did not so I was able to reuse both front and rear carriers.
Side bar- axle seals are cheap, labor to do them is not. They're just labor intensive to get to them, though not difficult.
That being said- shade tree or not, the fault happened as a result of reinstallation. It should have been noticed by the operator but it's easy to overlook those as residual oil from the install. Usually you'll get a 500 mile break in and then you've got to change the fluid. At that point, he should have noticed it and mentioned that it needed more work.
Regarding the gear set on your differential carrier- that change is only necessary (to a different carrier) if the vehicle originally had the 3.21 gears. Mine did not so I was able to reuse both front and rear carriers.
Side bar- axle seals are cheap, labor to do them is not. They're just labor intensive to get to them, though not difficult.
In general, it sounds like a real crap situation unfortunately. It sounds like maybe you purchased the parts and took them to the shop? If so, this is the reason you always let the shop purchase the parts too. That way regardless of part failure or install error, it's all out of your hands.
03-18-2021, 07:36 PM
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I don't think I've ever multi-quoted so many in one post.
This is just total bulsh. Anyone telling you that 4.56 are "too big" have no clue what they are talking about. If they mean geared too low, that is a bunch of crap. If they mean "too big" as in they needed a different carrier, the ring gear literally wouldn't have bolted up to the old carrier. You could run that jeep with 5.38 gears which is as low as you could go, not adviseable with 35s, but even then you're not going to blow all the seals out, you'd just run really high RPMs.
I'd agree that the different weight of gear oil was not the difference maker here.
+1, as noted, the 4.56 gears literally wouldn't fit without the proper carrier. The ring gear bolts would not line up.
+1 here that the axle isn't being vented properly, and/or also likely they jammed the front shafts in carelessly and knicked the seals in the process. Anyone charging people to regear should know better though.
Literally no way to do a regear without pulling, and mangling, the pinion seals so those had to be replaced which I think is what you're getting at here. The front seals SHOULD have been replaced regardless. It's literally like 5 mins cuz everything is out anyhow. The rear seals do not get replaced during a normal regear (as Karl notes later).
The gears are chewed up cuz you lost that much gear oil and they weren't getting lubed, or cuz they eff'd up the regear in general? I mean, kinda sounds like they didn't have the pinion preload correct which lead to quick failure of the pinion seals. This could have lead to a lot more heat in general and failed axle shaft seals too I guess.
+1 on everything Karl said here and what I probably already reiterated above.
In general, it sounds like a real crap situation unfortunately. It sounds like maybe you purchased the parts and took them to the shop? If so, this is the reason you always let the shop purchase the parts too. That way regardless of part failure or install error, it's all out of your hands.
This is just total bulsh. Anyone telling you that 4.56 are "too big" have no clue what they are talking about. If they mean geared too low, that is a bunch of crap. If they mean "too big" as in they needed a different carrier, the ring gear literally wouldn't have bolted up to the old carrier. You could run that jeep with 5.38 gears which is as low as you could go, not adviseable with 35s, but even then you're not going to blow all the seals out, you'd just run really high RPMs.
I'd agree that the different weight of gear oil was not the difference maker here.
+1, as noted, the 4.56 gears literally wouldn't fit without the proper carrier. The ring gear bolts would not line up.
+1 here that the axle isn't being vented properly, and/or also likely they jammed the front shafts in carelessly and knicked the seals in the process. Anyone charging people to regear should know better though.
Literally no way to do a regear without pulling, and mangling, the pinion seals so those had to be replaced which I think is what you're getting at here. The front seals SHOULD have been replaced regardless. It's literally like 5 mins cuz everything is out anyhow. The rear seals do not get replaced during a normal regear (as Karl notes later).
The gears are chewed up cuz you lost that much gear oil and they weren't getting lubed, or cuz they eff'd up the regear in general? I mean, kinda sounds like they didn't have the pinion preload correct which lead to quick failure of the pinion seals. This could have lead to a lot more heat in general and failed axle shaft seals too I guess.
+1 on everything Karl said here and what I probably already reiterated above.
In general, it sounds like a real crap situation unfortunately. It sounds like maybe you purchased the parts and took them to the shop? If so, this is the reason you always let the shop purchase the parts too. That way regardless of part failure or install error, it's all out of your hands.