Can I use a 4L80 trans?

[custom10nut]

I’m beginning to consider changing out my TH350 trans for one of the Following.
1.700R4
2. 4L60
3.4L80
What are the Pros/Cons of each, in regards to Electronic Wiring and reworking, Trans Tunnel clearance or modifications required, Crossmember mods, and Driveshaft requirements.
I’m considering the changeover to one of these Transmissions, for the advantages of OD on the Highways.
Any advice is welcomed

[C101972]

It depends on how much horsepower that you have? If your engine is 500 horsepower or less. I would recommend a 700r4 from Phoenix Transmission. All you do is pick up the phone and call Phoenix Transmission, tell them what your truck information, motor, rear axle ratio, tire size, what the trucks purpose is? Towing or daily driver etc.. They will build the transmission to what you need, easy install with just a driveshaft shortened. Very good people to deal with and reasonably priced. A 4l80e will fit if your truck has the high jump floor otherwise you have to modify and you need a controller to run this transmission as well as a 4l60. Extra cost! I hope this helps your situation. Thanks Chuck
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[tim_mc]

Good info C101972. I've read good things about Phoenix Transmission in TX. I love my 700R4 - got lucky and had one built locally by an experienced GM transmission rebuilder. I swapped it for a TH350 with a mild SBC 350.

[Jiggers72-GMC]

Yes, what C101972 said, a 4L80 is way overkill in these trucks. A 700R4 with the torque converter lock up kit works great in my truck.

[tim_mc]

Second that on torque converter lock-up - it's like having a (tiny) 5th gear! My builder had an older style 82-89(?) valve body that supported the hydraulic lock-up kit, so no additional electrical wiring, brake light switch w/cruise control leads, low-vacuum switch or solenoid needed on my 700R4. I believe this is the kit he used:
https://transgo.com/product-details/...aulic-lock-up/

[custom10nut]

All these responses are. Great! This is just the information I needed.
Now I look for a 700r.
So there’s no electronic box or wiring needed?
What about the mount and drive shaft length?

[tim_mc]

No electronic box needed for 700R4. However, depending on the set up you may need to run a 12v power lead to the lock up solenoid. There are a couple of threads on the forum that cover this. Here's a pic on the transmission lengths. You will likely need to cut down the drive shaft, as I had to since my TH350 was the short tail shaft version. I had my local Inland Truck Parks cut and balance a spare 2-piece drive shaft and install a new carrier bearing after getting the transmission and measuring a couple of times to be sure of what I needed. I was able to slide the transmission mount back about 1" (if I recall correctly) and drill new holes using an extended drill bit to reach the upper rail. Based on the diagram, the 700R4 mount is about 3/4" further back from the TH350 mount.

Also, you will want a later 700R4/460L version (87-93 I think) as they were better built and had 30 spline input shafts (vs. 27 spline on earlier versions). My core is from a '92 Caprice.

[custom10nut]

Originally Posted by tim_mc

No electronic box needed for 700R4. However, depending on the set up you may need to run a 12v power lead to the lock up solenoid. There are a couple of threads on the forum that cover this. Here's a pic on the transmission lengths. You will likely need to cut down the drive shaft, as I had to since my TH350 was the short tail shaft version. I had my local Inland Truck Parks cut and balance a spare 2-piece drive shaft and install a new carrier bearing after getting the transmission and measuring a couple of times to be sure of what I needed. I was able to slide the transmission mount back about 1" (if I recall correctly) and drill new holes using an extended drill bit to reach the upper rail. Based on the diagram, the 700R4 mount is about 3/4" further back from the TH350 mount.

Also, you will want a later 700R4/460L version (87-93 I think) as they were better built and had 30 spline input shafts (vs. 27 spline on earlier versions). My core is from a '92 Caprice.

Thank you for the knowledge

[Accelo]

Originally Posted by custom10nut

I’m beginning to consider changing out my TH350 trans for one of the Following.
1.700R4
2. 4L60
3.4L80
What are the Pros/Cons of each, in regards to Electronic Wiring and reworking, Trans Tunnel clearance or modifications required, Crossmember mods, and Driveshaft requirements.

• 700R4
  This transmission is one of the easiest to convert. Requires moving the cross-member slightly to the rear and a shorter driveline. Use a 1987 to 1992 transmission for the best service. The 350's cooler lines can be reused with just a slight tweaking. Most of these transmissions have an analog speedometer output that can be used to run the factory speedometer in the C10's. All that is required is the plastic gearing with the correct ratio.
• 4L60
  This is the 4L60E I am assuming. Requires a computer to shift. If you are transplanting an electronic injected motor this is the way to go. You can run into issues getting the flex plate to torque converter spacing correct. Computer will run the lock up so no issues there. Since this is the same physical dimensions as a 700R4 (up to 2000) it requires moving the cross-member slightly to the rear and a shorter driveline. The 350's cooler lines can be reused with just a slight tweaking and adapting the snap in fittings if it has them. Adapting an analog speedometer can be interesting. Many only have provisions for electronic sensors. Especially true of the 2001 up 4L60E and 4L65E with the 6 bolt tail housings.
• 4L80
  Installing a 4l80 requires moving the cross-member to the rear. Also required are different transmission lines, a modified or swap harness with computer and associated inputs, and a modified driveshaft with a larger yoke and crossover U-joint. Otherwise, the stock shifter will still work and the factory ECM can control all of the 4L80E's functions.

The torque capacity of the 700R4/4l60E's are relatively close to the 350's and the 4L80E similar to the 400's. You didn't ask about the 2004R. It is a direct bolt in for the THM350. Same length, same cooler lines and output shaft spline count. Getting difficult to find and does not have the strength of the other transmissions. Upgrading a 2004R costs more than just using a 700R4.

[Bigdav160]

And just to clarify a couple points.

A 4L60 is basically the same as a 700R4. Hydromatic updated the Chevrolet design by adding a forward accumulator and a couple other modest tweaks in mid 1987.

Pickup trucks but not cars in 1993, electronic shifting and pressure controls were added and the the transmission became the 4L60e. No more governor and the electrical connector moved to the passenger side makes it easy to identify externally. Needs a computer, throttle position sensor and vehicle speed sensor to operate.

The 4L80e had always been electronic shifted and is, more or less, a TH400 (3L80) with an internal overdrive section added