Circle-D_Brian

The 6.0 LQ4 motors all came with the 4l80 transmission, but watch out for the 6.0 LQ9/LS2. Those came with the 4l60/65/70 style of transmission. These would have included the silverado ss, escalade, denali, tbss, and a couple others I'm sure.

-Brian

G-BODY-JAMES

iTrader: (1)

oh good to know, but what would be better to know is how to determine those engines when they are all sitting in a line up on the wreckers shelf? Are there any stampings numbers or anything that I guy could use to identify these engines as to not get the wrong flexplate

Circle-D_Brian

An easy identifier for the LS2 is the aluminum block. The LQ4 and LQ9 as far as I know are very similar externally, but you can always pull a spark plug and check for flat top (lq9) or dished piston (lq4). Some LS expert may know stampings or casting numbers that I'm not familiar with.

-Brian

slvr T/A

iTrader: (7)

So I have a truck I just got (didn't run). Got it to crank yesterday. It's a 6.0/4L60e and I'm having issues with the flex plate making a horrible grinding sound on the starter. I noticed it has a billet converter with 6 mounting bolts and it has a stock style (dished) flex plate. Looks like it has a "long" crank but not 100% sure. I compared flex plate to block clearance to my trans am and the truck's flex plate is definitely closer to the block. I shimmed the starter down a good bit and it's not as loud when running now but it sound bad when cranking over. Is the flex plate maybe on backwards or the wrong one is installed?

99pewtervert

Okay all. I have a huge issue. I am stuck and its driving me nuts, and I dont know what to do. I have a 99 z28 convertible. I replaced the motor in it due to a rod knock. I purchased a motor from a buddy of mine thats built for spray. Under his impression its out of a 04 GTO (his car he bought is a LS swapped 240 so he is going off what the previous owner said). It has the long crank style on it. My OE motor has the short crank. I have a stock 4L60E, and have a dished flex plate. I also purchased a used converter that I was told is a circle D 3800 stall with anti-ballooning for spray. I went to install it into the car and the TC butts up again the flex plate and locks. I had three different people check the TC install and all said it was okay and should be far enough in. Now, we went to a flat flexplate from a 6.0 and it gave us the room we needed but the bolts didn't line up. Also, no starter will work due to the flexplate sitting almost against the back of the motor. Can anyone help me with this? I am at a loss, and not sure how to get this to work, if at all. Not sure if I need a different TC or just a different flexplate or what as this is my first time dealing with this situation and my 1st Camaro.

Circle-D_Brian

I would like to see 3 pictures. 1, your two flexplates 2, your crank flange 3, the front cover of your converter. From there, I can let you know what you need to do for sure.

-Brian

axld

hey Brian, I have read all 3 pages trying to get mine straight, still confused , I have a 03 5.3/4L60E currently in car . I bought a 99/00 IRON headed LQ4. what do I need to bolt up to trans? . I was told" just oblong the 6.0 flexplate to fit my converter" was all that was needed.? Thanks axld .

Circle-D_Brian

The bolt pattern is the least of your potential problems with this combo. Drilling the flexplate is fairly simple, but the standard 4l60 converter is going to come with the longer LS length pilot to work with the dished flexplate. The 4l80 pilot is shorter. The front cover of a factory style 4l60 converter also has too much curvature to fit the flat 4l80 flexplate correctly.

In a nutshell, the easiest and cleanest way to do this would be to get a custom converter and use the flat 4l80 flexplate. You need a 4l60 converter with the 4l80 front cover. We do this for no extra charge in our Pro Series line if you're interested.

-Brian

rpturbo

iTrader: (47)

Brian, so your off the shelf GM 278mm HP 4L80 LS Torque Converter is setup for what flexplate configuration?

Circle-D_Brian

The HP Series 278mm converters require the dished 4l60 or 6l80 style of flexplate. The reasoning behind this is they start life as a 4l60 converter that we change the impeller hub, stator splines and input splines to fit the 4l80. It re-uses the 4l60 front cover though.

-Brian

98 4mula

iTrader: (7)

I'm trying to get my flexplate situation settled. I think I have it figured out. I bought an early LQ4 and a separate 4L60e. The 6.0 is a long crank and the 4L60 is from a 2002 4.8 (after running the numbers). I was given a dished flexplate and some long bolts with the engine. I picked up a pro torque LS converter. I think I'm going to need a flat flexplate with no spacer. Is this correct, thanks.

Circle-D_Brian

Since the long crank motor only ever came with the 4l80 automatic transmission from the factory, you are limited to running the flat 4l80 flexplate with the 11.5" bolt pattern. The 4l60 converter requires a dished flexplate with the smaller 11.06" bolt pattern. The pilot length will be too long as well. The 4l60 converter you have will probably not work unless it was custom built with the 4l80 bolt pattern and pilot length. It's something we do from time to time.

-Brian

98 4mula

iTrader: (7)

Hmmm, seems like I'm SOL. Either replace the crank with a short crank or get a new converter built for the long crank. The converter was built for an F-body LS. Thanks for the quick response.

98 4mula

iTrader: (7)

Is there a way to find out if my converter was made to fit a 4L80 as well. Thanks

Circle-D_Brian

If it was built for an F-Body, I'm guessing it does not have a 4l80 front cover. It's a pretty rare request. If you post a picture of the front cover, I can let you know for sure.

-Brian

98 4mula

iTrader: (7)

Circle-D_Brian

You sir might be in luck. That converter appears to have the 10.75" 11.06" and the 4l80 11.5" bolt pattern. I cant tell the pilot length from that angle, but you can turn the converter over and measure how far the pads are off the ground. The measurement you need will be 1/4". If it's over 1/2", then you will need to have the pilot machined down. If you take a picture of the other side, I can let you know if it fits the 4l80 trans or not.

-Brian

98 4mula

iTrader: (7)

98 4mula

iTrader: (7)

Thanks for the info Brian, it's much appreciated. I got a measurement of approximately.675 from the pad to the end of the pilot.

Circle-D_Brian

Ok, ditch the dished flexplate for the 4l80 flat flexplate. Then grind or machine the pilot down to about .300" pad to pilot height. That should do the trick!

-Brian