TRNW-2: 6L90, jmdz torque converter

[art landeck]

jmdz is a captive clutch many have successfully changed  them to a jmbx 
but i have a friend that got burned twice doing that and had a chatter 
he could not got rid of and went back with the captive clutch to solve 
the issue. Was it  just a stroke of bad luck or is there more to it. I 
have done it and it worked but not sure I would do it again.

Justin Merritt via trnw2 wrote on 10/29/2025 6:51 AM:
> We have seen a few of these converters. They don’t seem to go down as 
> bad as a jmbx. Talk to your supplier about core before deciding to use 
> a billet jmbx in its place. We just use a reman jmdz when we see it.
>
> Justin
> Sent from my iPhone
>
>> On Oct 29, 2025, at 5:35 AM, Fred Whitaker via trnw2 <trnw2 at trnw.net> 
>> wrote:
>>
>> 
>>   Not sure I have seen a JMDZ converter. But If I were overhauling 
>> it,there is no way I would use it over. ANY Transmission I overhaul 
>> with 140K would get a new converter. Captive clutch or not. I would 
>> simply replace it with a quality converter from a supplier you are 
>> comfortable with. I myself wouldn't mess with the programming. The 
>> first one went 140K with no problems.
>> ------------------------------------------------------------------------
>> *From:* trnw2-bounces at trnw.net <trnw2-bounces at trnw.net> on behalf of 
>> John Vanklavern via trnw2 <trnw2 at trnw.net>
>> *Sent:* Wednesday, October 29, 2025 4:14 AM
>> *To:* trnw2 at trnw.net <trnw2 at trnw.net>
>> *Subject:* TRNW-2: 6L90, jmdz torque converter
>> *Date:* Wed Oct 29 2:14:23 PDT 2025
>> *Subject:* 6L90, jmdz torque converter
>>
>> I have a 21 chevy hd in the shop with a jmdz converter. I'm wondering 
>> what you guys are seeing with these in comparison to the jmbx. Are 
>> they as prone to failure? The main reason I'm asking is because this 
>> trans had no fwd with ball stuck in plate. When I called customer 
>> about it, he wanted me to overhaul and update trans anyway. I'm not 
>> going to argue with gravy. Trying to figure out if I should replace 
>> converter or reuse. trans has about 140k on it. besides my question, 
>> a general discussion about this converter would be nice. I understand 
>> it is a captive clutch.
>>
>> John Vanklavern
>> Jvk Services Llc
>> West Olive, Michigan USA
>> TRNW Member Since: 5/23/2025
>>
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>
>
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