Swapped to a 4L80E
- Thread starter Otto J
- Start date
- Joined
- May 28, 2001
I asked Shane to sticky it.
- Joined
- Jan 18, 2011
I dont know how relevant the first part of this thread is being that its 5 years old but where Bob took over it sure is, with a complete parts list
- Joined
- May 28, 2001
Done.........
Followup notes on the HD-2 shift kit.
I used it because I wanted a set of springs and valves designed to work together. But I didn't use the 3-layer separator plate since I had heard of issues with cross-leaks. So I got a new plate, drilled the holes for the shifts, and did the internal dual feed mods during the build.
I did not install the 'pressure relief' components from the kit. I did use the heavy snap ring for the build. I chose the medium firmness level for the accumulator valve spring.
Bob
I used it because I wanted a set of springs and valves designed to work together. But I didn't use the 3-layer separator plate since I had heard of issues with cross-leaks. So I got a new plate, drilled the holes for the shifts, and did the internal dual feed mods during the build.
I did not install the 'pressure relief' components from the kit. I did use the heavy snap ring for the build. I chose the medium firmness level for the accumulator valve spring.
Bob
The earliest ones used a different harness and connector, and as time went on GM changed/improved some things. The later ones (97+ i think) had the cooler return line going further back ("rear lube"). One of the sprags is smaller in the later ones, but I don't think that makes it weaker.
The builders will have their own preferences and recommendations. I've heard some builders like the early ones, others the later ones. I think they will all work fine.
4wd transmissions don't have the reluctor for the rear speed sensor, but you can convert a 4wd trans its just an extra step or 2.
Bob
TCI adapter plates look to be backordered, Jegs has their clone of it in stock
434nova
Active Member
- Joined
- Sep 30, 2013
When running an adapter plate do you need to compensate for the extra spacing when you order the converter? How thick is the adapter plate?
HalfDozIN
Member
- Joined
- Sep 7, 2021
Some seem to be thin enough that it's a non-issue. The steel trans-dapt brand one I used is about .310" thick, and it came with a locating spacer for the converter hub, and a set of machined washers to make up the difference at the converter bolts. I would definitely get longer dowels for the block if using the thicker spacer like I did, though.
- Joined
- May 28, 2001
- Joined
- Jan 18, 2011
I use this company for my Big block Buick fuel systems, great stuff
Quick Turbo V6
Define stock!
- Joined
- May 24, 2001
I think those are more for if you have a problem with the alignment of the bell housing. You should just need longer dowels to compensate for the adapter plate.
SyrupPerMoose
New Member
- Joined
- Sep 25, 2023
Thanks for all the information! I am also in the process of swapping a 4L80 into my 87 GN. Sorry if I missed this, but did you use the original flex plate? And I'm assuming the pilot on the converter was spec'ed specifically for the 3.8?
Yes, stock original flex plate. The converter was spec'd for the engine/trans combination so it had the correct pilot, depth/height, and bolt circle.
I told them (Bison/PTC) about my adapter plate thickness and they included spacers for the mounting bolts.
The converter fits perfectly and drives great.
Bob
I told them (Bison/PTC) about my adapter plate thickness and they included spacers for the mounting bolts.
The converter fits perfectly and drives great.
Bob
SyrupPerMoose
New Member
- Joined
- Sep 25, 2023
That's awsome Bob, I can't find a reason not to do the swap. I've started playing around with Holley software on my ls/4l80 swapped C10 and it's fantastic. The things you can achieve once you do a few minor tweaks to the transmission (I also went the HD2 route less the pressure relief mod) is endless. How did you find the longer first gear worked out? I'm assuming it would be negligible with a higher stall. You mentioned it felt a little tight after driving it, do you still feel that way now? And just to refresh my mind what was the final stall that went in?
I laughed out loud when I read your comment about the "anointed ones"
I know 1000% what you're talking about. Some people just know more than you and you have to accept that lolI think what I said was that my previous 9.5"/10" lockup (5 years ago or so) felt a little loose. this one feels pretty much exactly like my 9.5" non-lock. So I feel that it drives perfectly (not tight , not loose)
I thought I would notice the first gear, but I don't. Not at all. The converter likely is the key here. I do notice that 4th has a little less overdrive. But thats just a tiny thing, and really the only thing I notice other than it just drives great
I thought I would notice the first gear, but I don't. Not at all. The converter likely is the key here. I do notice that 4th has a little less overdrive. But thats just a tiny thing, and really the only thing I notice other than it just drives great
SyrupPerMoose
New Member
- Joined
- Sep 25, 2023
Right, that makes sense since in OD you would be cruising at a steady state as opposed to rolling right out of first.
What made you go with a non-lock up?
I'm running a billet single-disk PTC in my 4L80E, I had several different converters in my 200 over the years so all the comparisons to the non-lock PTC and the earlier lockup PTC were to them. This single-disk drives great. I have an issue with my lockup solenoid at the moment, so I've been driving it around unlocked (like to North Carolina and back...) .
Bob
Bob
