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Looking for some guidance. I have a 4l80 behind a 4.3 v6 in a GMC Typhoon. Swapping to a LQ9 and am trying to determine the flexplate I need.
My converter is a Jakes unit with 3 bolts and a 9 3/8 and 10" bolt pattern. End of pilot to pad measurement is about 0.1875"
Is it possible to use this converter on the LS or will I be better off going with a 6 bolt TC?
Looking for some guidance. I have a 4l80 behind a 4.3 v6 in a GMC Typhoon. Swapping to a LQ9 and am trying to determine the flexplate I need.
My converter is a Jakes unit with 3 bolts and a 9 3/8 and 10" bolt pattern. End of pilot to pad measurement is about 0.1875"
Is it possible to use this converter on the LS or will I be better off going with a 6 bolt TC?
Thanks
You can probably find a flexplate to make that converter work. I would re-measure the bolt patterns. The 3 common ones are 10.75", 11.06" and 11.5". From there I can recommend a flexplate.
I've been reading up on this subject and I think I'm just more confused. I'm looking to get the right flex plate for my setup. I have a 2002 LQ4 6.0L and a 4l60E I bought from Performabuilt. Converter is a 4L60E Yank converter. Currently the transmission bolts up to the engine just fine and I have the correct clearance between flex plate and torque converter. However, the bolt pattern in the flex plate appears to be just a bit larger than the bolt pattern on the converter. I'm guessing that this is because the flexplate is for a 4l80e. What flexplate can I use to make this work? I assume my LQ4 has the short crank because its using a flat flexplate with a spacer.
Installing a long crank 6.0 with a 700R4. After reading this thread, Is there a flat flex plate that will work with the 700R4 converter for this application?
Last edited by Baldguy; 08-01-2019 at 05:06 PM.
Reason: Correction
Still a little confused after reading the thread a few times. So I'll ask for confirmation and hopefully can get some clarity through the wisdom of the folks here. I have installed a ls1 out of a 2004 gto with a short crank. I did upgrade to a TCI 399754 flexplate and still noticed a 1/4" gap between the TC and the flexplate after installation. I'm wondering what is an acceptable gap as in order to tighten the flexplate to the TC as it moves forward that 1/4" I'm pulling the tranny out in the next day or two to install a new stock converter in that I have but I believe adding a pilot spacer it would be too tight. I cannot tell in the original few posts if it is recommending that I need to add this with the flexplate.
I think I'm hosed, but thought I would at least ask the question.
I have a Circle D converter for my 4L80 and am running a long crank LQ4. I have just over .6" from mounting tabs to end of snout on converter.
I know at a minimum I need a flat flexplate with the 4L60 pattern, but is my converter usable or do I need to find something else? Wondering about just milling .3" off the end of snout??
Are you saying that if you put the converter on a surface plate, the "snout" is up .6" taller than the bolt pads? If so...that's how it's supposed to be.
If I'm misunderstanding you, ignore my next comments and explain what you mean.
If you have a long crank LQ4...then just treat it like a short crank motor with the spacer.
That spacer just adds back the distance.
So, you need a flat flexplate with the bolt pattern to match your converter bolt pattern, and that should be it.
Being active here again, I have deleted over a dozen posts in this thread - mostly unanswered questions and anything not related to flexplates.
I will also trim this thread further by deleting repetitive questions and answers that are unlikely to help future readers.
Please read and re-read the first few posts by myself (which was co-written with Circle-D) and Circle-D. If still confused, you can post your specific question here and hopefully it will be answered. However once answered, I may decide to delete your post and its answer if it seems redundant. Please do not be upset if your post gets deleted here; I think this will allow a good balance between information and questions without becoming a ridiculously long thread.
I have a question can I mate a 99 lq4 to a 2004 4l80e Trans? I have a 04 6.0 and I sent the rods through the block. Really want to rebuild it because it was my older brothers when he was in highschool 6 years ago and he gave it to me as a gift on. I’m now 18 and my brother has been deployed to Afghanistan and I found and bought a 99 6.0l lq4 with 84k on it, only spent a $1000 so far. I’ve heard that it’s not going to work but I’m very determined ( on a budget) the truck itself has 250k and many say it’s not worth it but the truck has a lot of sentimental value to me.
Did you bother to read. I mean COME ON people.
This is your first post, so I'm assuming not.
Go read this thread and you will have your answer. @mrvedit might have a nicer answer for you.
you should be able to run the flexplate that is on the 04 engine on the 99
If the 99 is a "long crank" then don't use a spacer
if the 99 is a "short crank" use the spacer
In short:
The SBC and similar LT engines all had what we now call a "long" crank and mate to any 4L80E, 700R4 and "LT" style 4L60E. Some of the '99 and '00 LS1 truck engines also had a "long" crank so that they could mate directly to a 4L80E.
However all other LS engines have a "short" crank and mate to the "LS" style 4L60E. To use a 4L80E, 700R4 or "LT" style 4L60E you need a spacer.
There are some exceptions, but that covers most cases.
The flexplate issues are described in the thread, in some case a different flexplate is needed or the holes need to be elongated a bit.
Maybe someone knows all the details, but I sure don't know how to predict whether a '99 or '00 truck LS1 is short or long crank. Which is why MaroonMonster did not give you a specific answer.
In short:
The SBC and similar LT engines all had what we now call a "long" crank and mate to any 4L80E, 700R4 and "LT" style 4L60E. Some of the '99 and '00 LS1 truck engines also had a "long" crank so that they could mate directly to a 4L80E.
However all other LS engines have a "short" crank and mate to the "LS" style 4L60E. To use a 4L80E, 700R4 or "LT" style 4L60E you need a spacer.
There are some exceptions, but that covers most cases.
The flexplate issues are described in the thread, in some case a different flexplate is needed or the holes need to be elongated a bit.
Maybe someone knows all the details, but I sure don't know how to predict whether a '990 or '00 truck LS1 is short or long crank. Which is why MaroonMonster did not give you a specific answer.
Some of those odd-ball engine years in regard to crankshaft flange thickness are determined by original transmission combination.
As you said; a 4L80E transmission would have to paired with the engine... and in those years would have the thicker crankshaft flange.
Also for Gen I small block Chevy engines... the engine has to have a One-piece real main seal to have the thicker crankshaft flange.
Gen I engines with a Two-Piece rear main seal have a completely different crankshaft flange (and those even varied depending on displacement and main-journal diameter).
So I have read this thread and I couldn't find an exact answer to my situation.
I have a 1999 c1500 suburban with an LT style 4l60e trans with the 298mm torque converter. Well it just went out.
Anyway I was able to get a 4l60e out of a 2001 Sierra 1500 that has the LS style bellhousing with the 300mm torque converter.
Now should the torque converter just bolt right up to my flexplate or do i need to get a different one? And if so, then will I need to get a new starter as well?
While I started this thread 7 years ago, I have forgotten many such details.
Someone correct me or confirm, but I'm reasonably confident that the 300mm torque converter will either bolt up directly or the three holes in the flexplate only need to be elongated a bit.
I am a bit concerned whether your 1999 C1500 engine has the long crank or the short crank. If long crank, the LS style 4L60E will not bolt up at all. (But I think all the long crank models came with a 4L80E.)
If you decide to remove the 300mm torque converter to check the bolt fit, be sure to fully install it on the trans again - the mounting pads need to be a bit over 1" recessed from the mating surface of the bell housing.
Hopefully one of the experts here can correct me or confirm.
Hi
This post is super informative, thanks! I am trying to fit a LS style 4L60e to a gen 1 small block. I anticipate I will be able to achieve this by using a dished flexplate and machining a separator plate to push the trans away from the block a little, though I still have some measuring to do. Anyway, to my question...
I see you have the LS flexplates at an 11.06 bolt circle. I see this number quoted a lot.. but I also see a lot of parts quoting 11.25". Everything on Rock Auto with an LS motor seems to quote 11.25 and when I check the parts on the manufacturers' sites, they say 11.25" as well. Are there two patterns for LS or are they quoting the wrong number??
01-27-2019, 07:22 PM
