Determining which torque converter is actually installed

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

Asking this because I had planned on doing some transmission upgrades around the Thanksgiving timeframe, but am now wondering if everything I had been considering is really necessary.

Background: about 18 months ago, while the CRD was pretty much entirely bone-stock, I used MPPS to flash Yeti's 811 EGR/FCV delete + Stage 2 Hot tune (vers 1.02). This is the tune that the CRD has been running on ever since, and should have a torque output of 450Nm (330lb./ft.). At no point have I ever experienced torque converter chatter or transmission overheating with this tune, even when towing.

According to the sticker on the upper radiator cross-brace, this KJ did have the F37 recall performed on it. But what I don't know is if the original converter was replaced with the Euro unit as part of (or subsequent to) that, if there's something even beefier in there, or if I just happen to have the most resilient North American-spec torque converter known to man.

Short of dropping the transmission and eyeballing, is there any way to find out what might be in there?

ebbnflow · **Posted:** Tue May 14, 2019 1:41 pm

There is no way to know what TC is in your Jeep. Even dropping the trans will still present a mystery as the factory TC's have no identifying marks/part numbers on them. I'd say if you can put the pedal to the metal and you don't get shutter, then you've got a good TC.

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Mountainman · **Posted:** Tue May 14, 2019 4:08 pm

ebbnflow wrote:

There is no way to know what TC is in your Jeep. Even dropping the trans will still present a mystery as the factory TC's have no identifying marks/part numbers on them. I'd say if you can put the pedal to the metal and you don't get shutter, then you've got a good TC.

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X2, and you probably got an updated front pump also. I wouldn't touch it as you are very lucky. I'm on my third swap, as the public knowledge of the root cause (front pump valve) wasn't out there yet. At least I can install an even lower stall converter while I'm in there, a fairly recent discovery also.
Oh, you most likely (99%) have a Euro converter...

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

ebbnflow wrote:

There is no way to know what TC is in your Jeep. Even dropping the trans will still present a mystery as the factory TC's have no identifying marks/part numbers on them. I'd say if you can put the pedal to the metal and you don't get shutter, then you've got a good TC.

Thanks. This is pretty much what I suspected, but good to have confirmation.

Mountainman wrote:

X2, and you probably got an updated front pump also. I wouldn't touch it as you are very lucky. I'm on my third swap, as the public knowledge of the root cause (front pump valve) wasn't out there yet. At least I can install an even lower stall converter while I'm in there, a fairly recent discovery also.
Oh, you most likely (99%) have a Euro converter...

Good to know, and appreciate it. There's a part of me that wants to swap it out for a Suncoast anyway (which would be a useful upgrade), but if I don't have to budget for that I'm not going to complain

Mountainman · **Posted:** Wed May 15, 2019 6:19 pm

casm wrote:

ebbnflow wrote:

There is no way to know what TC is in your Jeep. Even dropping the trans will still present a mystery as the factory TC's have no identifying marks/part numbers on them. I'd say if you can put the pedal to the metal and you don't get shutter, then you've got a good TC.

Thanks. This is pretty much what I suspected, but good to have confirmation.

Mountainman wrote:

X2, and you probably got an updated front pump also. I wouldn't touch it as you are very lucky. I'm on my third swap, as the public knowledge of the root cause (front pump valve) wasn't out there yet. At least I can install an even lower stall converter while I'm in there, a fairly recent discovery also.
Oh, you most likely (99%) have a Euro converter...

Good to know, and appreciate it. There's a part of me that wants to swap it out for a Suncoast anyway (which would be a useful upgrade), but if I don't have to budget for that I'm not going to complain

The more aggressive converters require more line pressure to avoid shudder. So, you'd want to add the upgraded pump to the budget, which would never pay. Who knows, maybe there's a new pump and suncoast in there also

Dez · **Posted:** Wed May 15, 2019 11:50 pm

I have a even hotter tune then what yeti offers and my tc only shudders at 55mph and only when I push it far enough to speed up but not drop a gear. On stock tc with f37 recall. Doesn't do it any other time. If I hadn't of figured out when I could make it shudder I may of never felt it for myself lol.

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

Dez wrote:

I have a even hotter tune then what yeti offers and my tc only shudders at 55mph and only when I push it far enough to speed up but not drop a gear. On stock tc with f37 recall. Doesn't do it any other time. If I hadn't of figured out when I could make it shudder I may of never felt it for myself lol.

I can confirm that I'm not seeing this behaviour, and I'm *very* aware of how things behave at around 55mph - it's one of my favourite places to swear at the person who came up with the TCM programming whenever I try to overtake another vehicle from about that speed

Interesting that you're not seeing any shudder either, though. Which tune are you running?

DieselJeepLuvr · **Posted:** Mon May 20, 2019 10:42 pm

You could do a Carfax report on it to find out all the service records and contact all to see if anyone did the upgrade. Also If you're not towing in the mountains you may never notice a shudder. Also if the PO added a couple of tubes of Lubeguard Instant Shudder Fix. You may not have any issues with a stock TC. If you plan on keeping the rig then I'd definitely consider upgrading the front pump and getting a Suncoast TC. But in the mean time run it until it explodes.

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

DieselJeepLuvr wrote:

You could do a Carfax report on it to find out all the service records and contact all to see if anyone did the upgrade.

Pulled one when I bought it (this CRD was an eBay find). Nothing on there. If I can get the local dealer to cooperate, I may try to pull a VIP report.

Quote:

Also If you're not towing in the mountains you may never notice a shudder.

I've done that with 3000lbs.-plus on the back, and never felt a thing.

Quote:

Also if the PO added a couple of tubes of Lubeguard Instant Shudder Fix.

If they did, it's long gone - the transmission fluid was changed immediately after it was purchased along with the coolant, power steering fluid, transfer case, and front & rear diffs.

Quote:

You may not have any issues with a stock TC. If you plan on keeping the rig then I'd definitely consider upgrading the front pump and getting a Suncoast TC. But in the mean time run it until it explodes.

I hear you, and the drive-it-until-the-wheels-fall-off approach is the one I'm taking. I'd just like to know what's in there.

WWDiesel · **Posted:** Wed May 22, 2019 11:10 am

casm wrote:

I hear you, and the drive-it-until-the-wheels-fall-off approach is the one I'm taking. I'd just like to know what's in there.

Only sure way; install a new one then you know what you got and never look back.
Painful on the front end, but in the long run you will be much better off knowing what you have, its capabilities, and having a new front pump assembly installed as well.
Worn front pump parts can cause some weird issues!

Many have "been there, done that"... :banghead:

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

WWDiesel wrote:

casm wrote:

I hear you, and the drive-it-until-the-wheels-fall-off approach is the one I'm taking. I'd just like to know what's in there.

Only sure way; install a new one then you know what you got and never look back.
Painful on the front end, but in the long run you will be much better off knowing what you have, its capabilities, and having a new front pump assembly installed as well.
Worn front pump parts can cause some weird issues!

Many have "been there, done that"... :banghead:

I hear you on all of the above, and agree - but until there's a known issue I'd prefer to not upgrade. Yep, that could be a side-of-the-road moment. This is why I have the 200-mile AAA tow

Determining which torque converter is actually installed

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