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View Full Version : hidden costs installing 4L80 transmission in non computer non LS motor



chpr1972
03-21-2021, 05:50 PM
I was thinking of replacing my TKO600 with a 4L80. Yes, I know, but I have a bad left ankle and other health problems so it is getting about time. I wanted to buy a later model used one with converter instead of an early one so I did not have to have it rebuilt. First, what are they, and what are the hidden parts that will be expensive. Like I was told it would bolt right up to my BBC using a flexplate that I already have. then I found out yesterday that I need a special adapter or special flexplate that costs in the neighbor hood of 300 bucks. Then I find out that the old bent lines from one of my old automatic transmissions will not work. What do I have to do to put cooler lines on it? What does it cost. I have a 400R4 shifter out of a 89? Camaro I was going to use. So can I use that shifter and cable? Do I need to buy a specific lever at the transmission? I know about buying a transmission controller and drive shaft might not fit. But the yoke should. I have a Centerforce crossmember I plan on making work. Then I heard that you have to have a throttle position sensor on the carb. That will not be a problem for me, as I have a HP EFI. My radiator has a transmission cooler, and I hope to use it. I just can't afford expensive surprises. I guess I will detune my 489 BBC to 427 and a 700R4 .The reason why I wrote this is to let other people know what are the hidden surprises that will pop up and what they cost.

mean buzzen half dozen
03-21-2021, 06:34 PM
What car is the 4L80E going in?

chpr1972
03-25-2021, 06:23 PM
66 Lemans conv with 489 BBC

mean buzzen half dozen
03-25-2021, 06:41 PM
I believe the trans tunnel would be too tight to fit without modifying.
These will fit a tight trans tunnel https://www.ebay.com/itm/6AN-x-1-4NPSM-For-4L80E-GM-Transmission-Oil-Cooler-90-Degree-Banjo-Fittings-USA-/393065155257?hash=item5b84824ab9

I do not think a standard or even a HD flexplate would cost that much? Adapter, for what?
I bolted up my 4L85E trans to a 1969 inline 250 6 cylinder, it bolts right up. Same pattern as SBC & BBC

Shifter, cable, & lever might work for you. I used a Hurst shifter designed for a 700R4 for my 4L85E & it works.

Transmission cooler lines, not much money for straight pieces of metal tubing you bend yourself with fittings + hose $50 ish, also not a whole lot of money for -6 AN hoses to be custom made less than $200 ish

chpr1972
03-29-2021, 08:29 AM
Thanks, mean buzzen half dozen. Steel lines I can handle. My fuel lines on my FI added a couple 3 hundred bucks, buying adapters for different fittings. 4 fittings on my TPI cost $43 to $46 bucks each plus hoses. Just adapting from old to new style fitting was expensive with steel lines.