I'm tired of trashing 700R4's every 35K so I'm looking to upgrade to a 4L80E. Anybody have any information on what all is involved for an 85 IROC-Z???? I know that I'll have to shorten the drive shaft and add a computer off of a diesel to run the trans. Who burns custom chips for the trans computer??? Does the shifter for the 700R4 work with the 4L80E?????

Also, will a 90-92 computer handle the shifting of the 4L80E? There is supposed to be a California smog legal computer upgrade for my 85 to the later model MAP system. This would greatly simplify things if the computer will do that...... Seems like they were used with the 4L60E.....

Since I just lost 3rd and 4th gear Friday, I need any info I can get ASAP so I can get the ball rolling and the car back on the road!!!!!!



PS: Merry Christmas everyone!!!!!!

The January issue of "Super Chevy" has a article on
swapping the 4L80E into a Second gen camaro.
It's not a Thirdgen, but it could give you an idea on which direction to go.

I have read about a seperate trans controller sold by TCI? Also, GM is offering a 4L65E, which is a beefier trans than the 4L60E, and from what I read it has instructions for swaps into earlier vehicles, like 3rd gens, and swaps into later models, like my 4th gen Ram Air. Maybe this could solve your problem?
:rockon: :rockon:

Here is alittle more info on the 4L65E.

http://www.superchevy-web.com/tech/0311sc_4l65e/

You will need a standalone computer from an early Diesel truck that has been reprogrammed to shift at V8 points. Your computer has no ability to control shifting, it just locks and unlocks the converter.

The trans will bolt up fine with the right flexplate for your motor, and a 4L80E converter.

Your driveshaft will most likely need to be shortened.

You will probably need some kind of trans crossmember with a torque arm mount attached, because the trans won't have a mount provision for this like a 4L60E or a 700R4 from an F-car will.

Your stock rear, if you are still running it, won't be long for this world...

look for a manual valvebody

that would eliminate the need for a TCM

Thanks for the help guys!!! It confirms a few things I already new, brought to light new problems (torque arm attachment) and gave me another place to look for information.

BTW, I've rebuilt the rearend 3 times already.... Ripped teeth off the ring gear twice and the last time off the pinion gear. A 12 bolt is on my wish list... along with an Accel DFI computer....

:hail:

The manual shift valve body is a pain in the rear. You have to down shift two gears to get passing gear many times. I have a B&M ratchet shifter in my car that is great for the track, but is a pain in the rear if you are going to use it with a manual valve body. BTDT

After reading up on the 4L65, Idon't think it's worth the hassle. It's 3" shorter which would require me to get another driveshaft and I just installed a new aluminum unit about 6 months ago. It also doesn't help me in the area I need it the most. More clutch disks or larger diameter clutch packs for 3/4 gears.

My transmission already has the extra friction packs (7) and the Corvette servo, Transgo shift kit, Gil Younger upshift valve. I tried to find the police full throttle upshift using the number listed in the tech articles a couple of years ago and the Chevy parts guy at the dealership said it was bogus. If you have been able to use that number somewhere in the last 6 months, please post where you got it and how much.

Part of the reason why this transmission went this time was the shift points at low speed cruising were all screwed up. It shifted at 5500 on top but I couldn't get it to upshift at cruising below 2750. that meant I had to get to 45 just to get into 3rd gear. I installed a stock governor and it shfted fine at cruising, but upshifted at 3500 at full throttle and no passing gear. So..... I added the ratchet shifter.

The shifter was great for the strip but a pain in the rear when you needed passing gear. Finally I took the modified governor (which had lost a spring by now) and took one off the stock governor and put them together. Shifted perfectly around town and I had passing gear back. It also upshifted to the next gear when floored @ 5000 in Drive and 5200 if in 3rd. I still have the ratchet shifter to shift at 5500 at the track.

I think maybe I damaged the trans by upshifting into a higher gear too soon when I had the stock governor in it. I'm seriously considering buying a DVD on rebuilding a 700R4 and doing it myself. I figure $400 for parts and any tools I don't already have. Anybody know any sources for rebuild instructions??????