Bolt Spacing on Flexplate Different?
Thread Starter
Joined: Jan 2011
Posts: 1,921
Likes: 80
From: North Houston
Bolt Spacing on Flexplate Different? I pulled my 4l60e from the back of my LS1 the other day with the plan of servicing the trans filter and swapping converters. First, that stupid little o-ring for the filter wouldn't come out/go in without much more fight than I thought should be necessary! But that's over with... Second, the 8 bell housing bolts were RIDICULOUS to get to! Even with a 2' 3/8" extension, swivel sockets and wobble extensions, I spent entirely too much time getting those suckers out! I ended up having to drop the k-member in the back a little to get access. Awful. 
Finally, the coup de grace was discovering something that brings me to my question. When I installed the tranny and current converter about 500 miles ago, I bought a Quicktime flexplate RM-991 from eBay for LS1s with 4l60e transmissions. I didn't think twice, just bolted it up, got the stall installed (came with the transmission, I believe it is a 10.5" billet converter IIRC) and went along my business. Now I tried bolting up this new, "stockish" converter (stock size) for my application ('00 Z28) and ruined a hole in the converter. Upon further investigation, the new converter is about 9.5" from each mounting hole to the next. This is about .25" too far for the flexplate mounting points, which worked fine with the other ls1/4l60e converter!
So my question is this: was my Quicktime flexplate not REALLY meant for an LS1/4l60e combo and I just got lucky with the converter bolting up? If that's the case, what is the flexplate's intended application? Like, LS1/TH400 or LS1/TH350?
Here's the ad: http://www.ebay.com/itm/QUICKTIME-RM-991-SFI-RATED-29-1-LS1-AUTOMATIC-OEM-FLEXPLATE-TO-4L60-TRANSMISSION-/251227794827?pt=Motors_Car_Truck_Parts_Accessories&hash=item3a7e57ed8b&vxp=mtr
Finally, the coup de grace was discovering something that brings me to my question. When I installed the tranny and current converter about 500 miles ago, I bought a Quicktime flexplate RM-991 from eBay for LS1s with 4l60e transmissions. I didn't think twice, just bolted it up, got the stall installed (came with the transmission, I believe it is a 10.5" billet converter IIRC) and went along my business. Now I tried bolting up this new, "stockish" converter (stock size) for my application ('00 Z28) and ruined a hole in the converter. Upon further investigation, the new converter is about 9.5" from each mounting hole to the next. This is about .25" too far for the flexplate mounting points, which worked fine with the other ls1/4l60e converter!
So my question is this: was my Quicktime flexplate not REALLY meant for an LS1/4l60e combo and I just got lucky with the converter bolting up? If that's the case, what is the flexplate's intended application? Like, LS1/TH400 or LS1/TH350?
Here's the ad: http://www.ebay.com/itm/QUICKTIME-RM-991-SFI-RATED-29-1-LS1-AUTOMATIC-OEM-FLEXPLATE-TO-4L60-TRANSMISSION-/251227794827?pt=Motors_Car_Truck_Parts_Accessories&hash=item3a7e57ed8b&vxp=mtr
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Joined: Aug 2010
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From: Ann Arbor, MI
Noticing that no one has answered yet, I think it would help to post some additional information:
1. The distance between the converter holes in your flexplate.
2. The distance between the holes in your converter.
3. Confirm this is a 2002 trans and you are re-installing the original converter.
I don't have personal experience, but I frequently read that when people hook up an older trans (e.g. TH350 or pre '98 4l60E) they need to enlarge the flexplate bolts. So this does sound like a flexplate to retrofit older transmissions.
1. The distance between the converter holes in your flexplate.
2. The distance between the holes in your converter.
3. Confirm this is a 2002 trans and you are re-installing the original converter.
I don't have personal experience, but I frequently read that when people hook up an older trans (e.g. TH350 or pre '98 4l60E) they need to enlarge the flexplate bolts. So this does sound like a flexplate to retrofit older transmissions.
Thread Starter
Joined: Jan 2011
Posts: 1,921
Likes: 80
From: North Houston
Noticing that no one has answered yet, I think it would help to post some additional information:
1. The distance between the converter holes in your flexplate.
2. The distance between the holes in your converter.
3. Confirm this is a 2002 trans and you are re-installing the original converter.
I don't have personal experience, but I frequently read that when people hook up an older trans (e.g. TH350 or pre '98 4l60E) they need to enlarge the flexplate bolts. So this does sound like a flexplate to retrofit older transmissions.
1. The distance between the converter holes in your flexplate.
2. The distance between the holes in your converter.
3. Confirm this is a 2002 trans and you are re-installing the original converter.
I don't have personal experience, but I frequently read that when people hook up an older trans (e.g. TH350 or pre '98 4l60E) they need to enlarge the flexplate bolts. So this does sound like a flexplate to retrofit older transmissions.
Regarding the additional information, I'll need to take the measurements again since I don't have that information in front of me. I'll be able to come back with the numbers in a couple days, but I recall the distance for the 2800 stall being within 1/16th of an inch from the spacing on the flexplate, and the spacing for the stockish converter to replace it being off of the flexplate spacing by almost a 1/4".
As for the trans, I'm at the mercy of the vendor who sold it to me! The car is a 2000 and I made sure to mention that when I ordered... but that comment on enlarging holes sounds VERY relevant. ****.
I'll follow up as things develop over the week...
Thread Starter
Joined: Jan 2011
Posts: 1,921
Likes: 80
From: North Houston
Alright, this is more complicated than I thought. Basically, I think I found the flexplate, it's on order from O'Reilly's, a Pioneer Automotive Industries FRA-471HD (not available in stores yet, but Pioneer has 199 in stock!). When I contacted Pioneer about my situation, they confirmed that there WAS indeed a difference in years on the CRANKSHAFT bolt pattern. I still don't know what kind of converter the 2800 stall is, but I may have solved the mystery of how to bolt my stockish torque converter to my 3.622" crank! I'm anxiously awaiting the new FRA-471HD to try it out!
Edit: I'm at a loss. I'm now told by a reputable source that the crank did not differ between years, only the 99-00 truck crank business. So I guess Pioneer is manufacturing flexplates with the wrong pattern. FML.
Edit: I'm at a loss. I'm now told by a reputable source that the crank did not differ between years, only the 99-00 truck crank business. So I guess Pioneer is manufacturing flexplates with the wrong pattern. FML.
Last edited by themealonwheels; Jul 5, 2013 at 11:48 AM.
Thread Starter
Joined: Jan 2011
Posts: 1,921
Likes: 80
From: North Houston
Alright, done. Turns out the second (new) torque converter that was sold to me was "boxed" wrong (says the tranny guy who bought it from his supplier), it's a TH350 converter. I forced him to take it back and got an LS1 4L60E torque converter. Fits perfectly, no issues.
So if anyone comes across this in a search, I guess TH350 converters have a slightly different bolt spacing compared with 4l60e converters. Why my local tranny expert didn't know this is beyond me.
So if anyone comes across this in a search, I guess TH350 converters have a slightly different bolt spacing compared with 4l60e converters. Why my local tranny expert didn't know this is beyond me.
