4l80 Tranny Questions

[byates2]

I have a 350 bored to a 390 stroked out pushing about 375 horse.

I want a tranny that can handle that power. From what i read the 4l80 is the best out there.

Anybody ever do this or have a similar setup?

I have a 67 c10 mostly stock. Its either the 4l80 or my mechanic said he can beef up a 700r4 to handle the power for around 2 grand.
Any input would be greatly appreciated!

[hugger6933]

I would go with the 4L80E. I put one in my 68 LeMans convert behind the LQ9 6.0. It is a big and heavy trans, I am gonna say you will need to change you hump over to a high hump to have some trans tunnel clearance. On the wiring there are several ways to go but the stand alone type wiring from the diesel truck from 92-93 -94 c-k 2500-3500 with the 6.5 turbo is the least expensive and maybe the easiest to find from what I have read. It will require a stande alone ecm for the trans functions or for much much more money like 1500 bucks you can get an aftermarket setup to run from a laptop that has adjustable shift points and all the bells and whistles. The 4L809E will probably take more hp and torque to run than the 700R4 will and if you get a good builder using the later stuff they can be made to hold up pretty good as well. The key as with anything is gonna be study up and learn as much about it as you can so you can go in eyes wide open before any decesions are made and any dollars are spent. Jim

[byates2]

i had the old two speed power glide. Did that option come with the low hump?

[68bowtie]

Not an expert but from what ive read the 4l80E is far better than the 700 but costs way more too and requires a computer like hugger said. I plan to use a 4l80E behind my 427. And yeah youll need a high hump. If you wont be cruising the freeways you should consider a turbo 400. Strong as the 4l80, just no OD.

Sounds like a cool truck.

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[SS Tim]

Really might want to look around at Bowtie Overdrives. They build O/D transmissions and for the 2K your mechanice is talking they can set you up with a number of choices (and a warranty). The 200R4 would be my first choice for a street truck as the 1-2 rpm drop is better. Hesperia is a short drive too from Acton, CA. http://www.bowtieoverdrives.com/index.shtml

[byates2]

Having had the powerglide previously, would I be able to use my old drive shaft and keep the cross member in the same spot? I was looking at dimensions, they seem pretty close
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[byates2]

If I went with the 200
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[SS Tim]

Read through the site and give them a call or even drop in. really think that it is going to be the best choice for you. But if a 700R4 is more to your liking they could fix you up. Size wise they are all very similar. Even if it fit an upgrade of the driveshaft is probably a good idea.

[byates2]

Do you know of any good places to get a driveshaft or have one made?
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[SS Tim]

Not in the Antelope Valley...

[byates2]

Any places on the web
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[hugger6933]

First off your truck, with a PG does not have a high hump. The high hump floors were in trucks that had big blocks or heavy 3/4 or 1 ton with the granny 4 speed or the 4wd type truck. I have not seen a regular 2wd truck that was a smallblock normal trans equiped with the high hump. The high hump is easy to spot as it is bolted in placed whereas the low one is of course made into the stamping of the floor. Now the other question about having a driveshaft built, the tv shows that I see on Saturdays from Nashville TN, when it is raining and I don't get to golf really have good things to say about DENNYS DRIVELINE SERVICE. I am sure they can be found on the web[as with anything else in the world weather you want it found out or not]

[Rob68c10]

One other thing to remember about deciding between the 700r4, the 2004r, and the 4l80 that hasn't been covered is how much power is going to be sacrificed. Yes that 4l80 is strong and will take a beating. But the 4l80 is going to suck a lot more power than the other two transmissions will.

[skorpioskorpio]

Honestly, I wouldn't put a 4l80e in unless you were having it worked through. Early ones had all kinds of problems with the electronics, I went through 3 of them in my '91 Suburban with a stock 200hp TBI 350.

1st one slipped like crazy when the truck was still under warranty, GM "fixed" it twice only to have the problem show up again weeks later both times, I went to the dealer and asked them to "replace" the trans, they refused so I went to their parking lot and continuously did first to reverse slams, told them I was going to continue to do them until the trans broke completely. They replaced it. It had a tad over 70,000 miles on it at the time and had had the fluids changed and filters every 25K. I had a 75,000 mile extended warranty.

2nd one lasted a bit over 100,000 miles then lost the direct drive clutch pack, so no 3rd and no reverse. Slipped like hell before it lost the clutch completely. It had fluid and filter changes every 25,000 miles.

3rd one has a bad solenoid B which again means no 3rd (and of course that means no OD either because you can't get there without going through 3rd) so it's a Powerglide now. That was a used trans out of a 6.5 diesel suburban with less than 50,000 miles on it that was gone over before it was put in, I put less than 5K miles on it, virtually all freeway. Still under warranty but the first 2500 miles I put on it was also the distance I was from the shop that rebuilt it.

The 2nd and 3rd 4l80s never towed anything or had rough service of any kind, never were low on fluid or had any other sort of abusive lives other than I drive a little spirited, well as spirited as you can drive a 3 ton truck with 200hp. To be fair the current trans is probably an easy fix, but still.

The first trans pulled a 26' car hauler cross country.

I never broke any of those 4l80s mechanically but all 3 had serious issues, and remember these were 3 different transmissions not the same one rebuilt and two were brand new from GM and the third rebuilt with all GM parts, all 3 were early to mid 90s vintage. All 3 used a new GM torque converter.

I don't give the 4l80 high praise. If I was building a high torque heavy vehicle now, I would either get a 4l80 built beyond GM specs like a TCI prepped trans or something, or do a TH400 and a Gear Vendors OD. In a lighter load small block I'd probably go with a 700r4 or a 4l60(E), just because they are plentiful and cheap to replace.

[MARKDTN]

You sure a '91 TBI 350 Suburban was a 4L80E? I thought that would be 700R4 which is completely different. Thought you had to have a BB or Diesel to have the 4L80E that early?

[skorpioskorpio]

Originally Posted by MARKDTN

You sure a '91 TBI 350 Suburban was a 4L80E? I thought that would be 700R4 which is completely different. Thought you had to have a BB or Diesel to have the 4L80E that early?

I think all the 2500s had 4L80Es, anyway mine did and the stupidly heavy 14 bolt rear.

[SS Tim]

Originally Posted by byates2

Do you know of any good places to get a driveshaft or have one made?

Checked with a friend who needed his shafts done for a late Jeep.
Ended up at and very happy with Wenco.

http://www.wencodriveshafts.com/

[ItsRandy]

I have a 4l80e with a low hump...fits great.

[Vintage Windmills]

Problems with the 98+ ones seem to be few and far between. There are alot of them in 6000lb HD's with 200k miles now still pulling strong. They do rob some power as stated though. A 700R4 built right would easily handle a 350. More an issue of torque than horsepower anyways.