TRNW-2: Identifying 8L series units

[Jim Mobley]

Steve,
The ATRA 2021 Expo book has a lot of this information in form Steve Garrett.
Also here is an article from Gears Magazine.

https://gearsmagazine.com/magazine/8l90-changes-and-updates-they-are-not-created-equal/

On Wed, Jul 9, 2025 at 7:53 AM Steve Everett via trnw2 <trnw2 at trnw.net>
wrote:

> Thanks Art ,
>            this unit has a 24285391 part number on the tag, and has 15 pan
> bolts,  they ordered an 8L45 paper and rubber for it,  but the tailhousing
> gasket is much larger on this unit than what came in the kit ?  according
> to that info it isn't a 90? maybe its a 50?  I may see if Reese down at
> Aamco U can dig up anything on identifying these ?
>
>     I pulled the top plate on the valvebody and all the dampeners are
> there and not a scratch on them anywhere, I'm pretty sure this valvebody
> was never run in anything,  not sure why or how it ended up on what was
> supposed to be a stock unit ?
>
>    Steve
>
> On Wed, Jul 9, 2025 at 10:40 AM Art Landeck <artrans at optimum.net> wrote:
>
>> Here is the answer AI gives
>> [image: bGVnYWN5_bd236d88-3f19-458b-a86a-3ccb9883f862.png]
>>
>> Identifying GM 8L Transmissions | Shared Grok Conversation
>> <https://grok.com/share/bGVnYWN5_bd236d88-3f19-458b-a86a-3ccb9883f862>
>> grok.com
>> <https://grok.com/share/bGVnYWN5_bd236d88-3f19-458b-a86a-3ccb9883f862>
>> <https://grok.com/share/bGVnYWN5_bd236d88-3f19-458b-a86a-3ccb9883f862>
>>
>>
>>
>> Sent from my iPhone
>>
>> On Jul 9, 2025, at 10:35 AM, Steve Everett via trnw2 <trnw2 at trnw.net>
>> wrote:
>>
>> 
>>    I can find nothing in any of the tech I have that helps to identify a
>> unit,  the tI'ag on the trans has 0XNL in big letters ,  assuming it works
>> like most GM units it is apparently a 2020 unit?  which would be correct in
>> a 2021 vehicle,  I'm sure the XNL would tell me something? I just can't
>> find anything that tells me what ?
>>
>>    I've agreed to work part time , 3 days a week at an Aamco here in the
>> Metro area,  and this is a stock unit they somehow ended up with,  another
>> builder built it and had left two thrust bearings out of it, and had at
>> least one of the snap rings indexed incorrectly, but when it get it all
>> back together I need to make note of what vehicles it will fit in ?   it
>> has a brand new GM valvebody on it that they don't remember buying ?
>>
>>    Steve
>>
>> On Wed, Jul 9, 2025 at 9:56 AM pat schulte <zzyzxpat at gmail.com> wrote:
>>
>>> I know that the 8L45/50s I have seen do not use a dipstick and the fluid
>>> check is in the pan, but I think the very late 90s have gone that way as
>>> well. Not a stupid question, I have wondered this myself.
>>>
>>> On Wed, Jul 9, 2025 at 6:32 AM Steve Everett via trnw2 <trnw2 at trnw.net>
>>> wrote:
>>>
>>>> This is probably a stupid question,  does anyone know a way to tell if
>>>> an 8L is a 45,50 , or 90 by looking at the outside tag ?   similar to how
>>>> we identify the 6L's ?  I'm going through a unit someone built to make sure
>>>> its correct, and was told it came from a 2021 V6 camaro, which according to
>>>> what I looked up should be a 8L45,  but its not
>>>>
>>>>    I've built 6 or 7 of these, but haven't figured out how to tell them
>>>> apart yet
>>>>
>>>>    Steve
>>>> This message was sent from the TRNW Technical Discussion Forum (trnw2).
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>>>
>>>
>>>
>>> --
>>> Pat Schulte
>>> AAMCO Transmissions
>>> Temecula, Ca.
>>>
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