Litens 920834A Alternator De-coupler Life Expectancy

95Z28A4 · **Joined:** Sun Mar 30, 2014 9:53 am **Posts:** 297

The alternator de-coupler in my wife's CRD is failing at 78k miles. I pulled the cap and saw the typical rust/dust. I ordered a new Litens 920834A from Advance Auto. Anyone have high mileage on a Litens 920834A? I am hoping this "upgraded" de-coupler will last at least 150K miles.

flash7210 · **Posted:** Mon Sep 14, 2015 8:59 am

I went 160,000 miles on my stock alternator pulley.
Probably a lot longer than I should have but it was still working ok when I swapped it for the upgraded litens pulley.
I see no reason why the new pulley should not last for 150k miles or longer.

95Z28A4 · **Joined:** Sun Mar 30, 2014 9:53 am **Posts:** 297

I just completed replacement of the alternator decoupler pulley with the upgraded Litens pulley. It took 1.5 hours to remove the alternator, swap out the decoupler and re-install the alternator. The old decoupler is seized. The decoupler went from quite to clicking to completely seized in less than 2 weeks. The CRD currently has 78,473 miles on it.

thefunk · **Posted:** Sun Sep 20, 2015 10:08 pm

Why the decoupler pulley? Why not a regular plain $5 pulley? What's the engineering behind it?

Rixram · **Posted:** Mon Sep 21, 2015 7:38 am

thefunk wrote:

Why the decoupler pulley? Why not a regular plain $5 pulley? What's the engineering behind it?

I am sure someone will have a technical answer, but with the way this engine hops about at idle, it'd put too much shock on the othet components.

I had a decoupling pully go tits-up, and it took out a serp belt pulley and contributed to the premature failure of the setp belt tensioner.

thefunk · **Posted:** Mon Sep 21, 2015 8:48 am

ahh, that makes sense, kind of. I've never seen it on other 4 cyl or 3 cyl diesels. So maybe this engine just idles abnormally rough? I wonder if adding a billet torque converter and/or engine tune would smooth things out enough that the decoupler is no longer necessary...I might have to find out. The thing is just a sprag clutch, I'm a little surprised they don't last longer.

thermorex · **Posted:** Mon Sep 21, 2015 8:54 am

As I know, all newer computer controlled engines have alternators with decoupler, mainly because alternator does not work 100% of the time, due to engine efficiency reasons. I am sure it has nothing to do with the engine running rough. It has to do with starting and stopping the alternator while the engine is running.

I think the decoupler failing is due to being a less heavy duty part than it should have been, this is why Litens came up with the updated part.

kissfan79 · **Posted:** Mon Sep 21, 2015 10:01 am

Hey guys....
So just to confirm...the Litens 920834A will indeed work on the Liberty CRD? I went to Advance Auto's website and pulled it up. It said to would not fit the CRD.

Thanks, Jim

flash7210 · **Posted:** Mon Sep 21, 2015 10:31 am

kissfan79 wrote:

Hey guys....
So just to confirm...the Litens 920834A will indeed work on the Liberty CRD? I went to Advance Auto's website and pulled it up. It said to would not fit the CRD.

Thanks, Jim

Yes, it will work.
I found a local guy who repairs alternators and starters. He had the pulley in stock and sold it to me for $50 and installed it onto my alternator.

kissfan79 · **Posted:** Tue Sep 22, 2015 2:48 pm

flash7210 wrote:

kissfan79 wrote:

Hey guys....
So just to confirm...the Litens 920834A will indeed work on the Liberty CRD? I went to Advance Auto's website and pulled it up. It said to would not fit the CRD.

Thanks, Jim

Yes, it will work.
I found a local guy who repairs alternators and starters. He had the pulley in stock and sold it to me for $50 and installed it onto my alternator.

Thanks. Did you pull the alternator off and take it to him or did you drive your Liberty to his shop and he installed it while the alternator was still on the vehicle?

papaindigo · **Posted:** Tue Sep 22, 2015 3:11 pm

Flash is correct and that's the PN for the updated grease filled pulley Litens recommends for the CRD although it is 2.5mm smaller in diameter which doesn't matter.

Website checks for parts fit are notoriously dicey and often infuriating especially the ones that won't let you search for a part without specifying a vehicle. Way too much "help" brought to you by idiots. Can you hear me O'Reilly Automotive?

flash7210 · **Posted:** Tue Sep 22, 2015 3:13 pm

kissfan79 wrote:

flash7210 wrote:

kissfan79 wrote:

Hey guys....
So just to confirm...the Litens 920834A will indeed work on the Liberty CRD? I went to Advance Auto's website and pulled it up. It said to would not fit the CRD.

Thanks, Jim

Yes, it will work.
I found a local guy who repairs alternators and starters. He had the pulley in stock and sold it to me for $50 and installed it onto my alternator.

Thanks. Did you pull the alternator off and take it to him or did you drive your Liberty to his shop and he installed it while the alternator was still on the vehicle?

Yes. I had to remove my alternator and take it to him.

Dennis MacGyver · **Posted:** Sat Jun 04, 2016 4:24 pm

About a 10 months ago and 15,000 miles I replaced my Alt. OAD clutch with a Mopar original 53013554AF. The thing is making noises again and causing a very slight movement to the tensioner which I replaced a year ago when I did the Alt. OAD / clutch I want to get on this quick before the tensioner fails again. The tensioner was rock solid, NO movement at all, when installed last August.

So you who have replaced with the Litens 920834A "new and improved" from Advanced Auto, how are yours performing?

This darn component going bad so frequently is BS!!

The best way to change it is with an air impact wrench, with the alt. on the bench. EASY job this way, maybe 1/2 hour total.

Found this thread too viewtopic.php?f=5&t=78875

Billwill · **Posted:** Sun Jun 05, 2016 3:27 am

The reason the original decoupler fails is that it is a dry system open to the envirement where water can get in and rust the spring...this rusting and friction is the cause of the "red dust". Eventually the spring seizes up or snaps.

The sealed greased Litens should work a lot better and I have only seen good reports on it on all the Jeep forums....I would replace my coupler on my 2002 CRD with a Litens coupler but trying to get one shipped here to SA from overseas is a major headache so I will have to go for the OEM one.

I read up a long story on why a decoupler is needed on 4 cylinder engines....the CRD and the 2.4L needs it while the 6 cylinder 3.7 Gasser does not need it. It has to do with the uneven pulse of the engine and the overun when shutting the engine off.

The alternator on the Jeeps never truly shuts off completely...the output voltage is constantly increased or decreased by the field coils pulsing down to ground at a varying rate using Pulse Width Modulation...this is the same as on the 3.7 L gasser which uses a fixed pulley. :wink:

95Z28A4 · **Joined:** Sun Mar 30, 2014 9:53 am **Posts:** 297

I installed the Litens at 78K miles (see OP) and it is still working quietly at 99K miles. Still too soon to determine if it will last longer than the OEM de-coupler.

Sir Sam · **Posted:** Sun Jun 05, 2016 12:13 pm

thefunk wrote:

ahh, that makes sense, kind of. I've never seen it on other 4 cyl or 3 cyl diesels. So maybe this engine just idles abnormally rough? I wonder if adding a billet torque converter and/or engine tune would smooth things out enough that the decoupler is no longer necessary...I might have to find out. The thing is just a sprag clutch, I'm a little surprised they don't last longer.

My 98 Mercedes 6cyl had it. I think most newer diesels will have it as well, at this point its a common 20 year old technology, though the stock one just doesn't seem to last as long as the alternator does.

Since there is an auto-tensioner if the pulley seizes up it will wear it out pretty quickly, the tensioner costs more than a rebuilt alternator.

Dennis MacGyver · **Posted:** Mon Jun 13, 2016 9:07 pm

Received the new style AOD Litens 920834A. Removed the Alt. to put it on and noticed the pulley had some lateral play in it. Removed the pulley with an impact tool but the small spacer behind the pulley was stuck on the Alt. shaft. I grabbed it with pliers and tapped the end of the shaft with a small hammer, lightly at 1st then harder until the end of the shaft mushroomed. Wouldn't budge. I then separated the case, placed it on blocks to separate it, after much persuasion it began to move. It popped off and I then found that the Alt. shaft surface that the housing bearing rests on was severely worn. The portion of the shaft where the AOD spacer rests upon had a huge burr on it locking the spacer in place on the shaft. Two of our local AutoZone's had the Alt, in stock. I still removed the new pulley that the AZ unit came with and placed the Litens 920834A on the new Alternator. Running fine now.

So if your Alt. pulley has lateral play in it, it could be the Aly. housing bearing or the Alt. shaft is worn causing wobble & noise from your AOD pulley.

Litens 920834A Alternator De-coupler Life Expectancy

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