TH400 Needs Overdrive... 4L80E swap? Bolt on OD?

[SasquatchOnDeck]

The 350 will probably be okay, after all, there were plenty of 3500s that came with 350s...700R4, that's a different story!

BTW, what is your gear ratio on your truck?

Believe it's 4.10, that's the only tag on the diff. that was a whole nother story that took a month of my life, and shed a lot of light on this truck i bought. LSS, that's how i found out it's a Dana, with a dually conversion, but i still have no clue if the axle is factory, or if the ratio has been changed for that matter. Only sure thing is that the vin decode shows it wasn't a factory dually. Glove box sticker was gone.
Probably gonna switch to a 33-34 ish inch tire when i get the flatbed, and go back to single wheel, hopefully that will match the gearing a little better for on road use.

 

[454cid]

Really? I figured after the dually delete with a wood flatbed, the thing would be light enough that a 454 would just be overkill and a 350 would do fine, but then again, that's why i'm here, i'm just guessing.

I didnt realize you were going to switch to srw... that should help, but I still think a tbi 350 would feel underpowered and suck gas if its having to work hard all the time. The 700r4 is too light duty. A wood flatbed may not be much of a weight savings depending on exactly what you build.

 

[SasquatchOnDeck]

I didnt realize you were going to switch to srw... that should help, but I still think a tbi 350 would feel underpowered and suck gas if its having to work hard all the time. The 700r4 is too light duty. A wood flatbed may not be much of a weight savings depending on exactly what you build.

fair. it shouldn't be doing too awful much, i did some obnoxious things with the rebuilt 350/700r4 in my 300k-ish mile c2500, but i've also heard of new 700r4s grenading after 20k miles in an S10... quality control is luck of the draw i guess. cross that bridge when i get there.

 

[stutaeng]

The real automatic transmission workhorses in the 8 lug trucks were the TH400 & 4L80e.

I've read some older posts here on guys saying basically the TH400 sucks and the 700R4 is awesome because it has OD... sorry, but that's not true on a heavy duty truck. The TH400 is legendary for a reason: the sheer strength and durability is unmatched in automatics. Give me another transmission that can beat it in strength...I don't think even the HD offerings from Ford or Dodge of the era can hang out with it...the dragster guys have figured this out many decades ago.

The GVWR and CWVWR numbers the units were rated for don't lie.

Just because the lighter duty transmission has OD doesn't make it better than the HD transmission with a direct high gear, again, in a case where you are moving a 6,000 lb truck. Forget about towing something heavy with it...

 

[Nad_Yvalhosert]

Really? I figured after the dually delete with a wood flatbed, the thing would be light enough that a 454 would just be overkill and a 350 would do fine, but then again, that's why i'm here, i'm just guessing.

Strange... when were you gonna tell us you were planning on de-dually-izing it?
We only know what you've previously typed, I looked back and couldn't find it.

Did you move the little ships in the Battleship game as a kid too?

 

[454cid]

Strange... when were you gonna tell us you were planning on de-dually-izing it?
We only know what you've previously typed, I looked back and couldn't find it.

Did you move the little ships in the Battleship game as a kid too?

I think he may have mentioned it in his other thread from a few monthes ago.

Oh battleship.....my little sister would move her ships. I didn't realize it until I had one hit but couldn't hit the rest of the ship!

 

[SasquatchOnDeck]

Strange... when were you gonna tell us you were planning on de-dually-izing it?
We only know what you've previously typed, I looked back and couldn't find it.

Did you move the little ships in the Battleship game as a kid too?

Well, It's gonna be run mainly on unlined country roads, where it's common for folk to do 50 in a 35 through the mountains, and when you're a foot and a half wider than normal and meet another car, **** gets squirrelly, quick. Plus, i'm not gonna be towing a house, and, i just never could dig the look, or the price of six tires versus 4. Personal taste more than anything, but it's gonna be a cruiser more than anything else. It just doesn't need to be super-ultra-heavy-duty.

And yeah, i did, but now i'm on to moving real Battleships.

The real automatic transmission workhorses in the 8 lug trucks were the TH400 & 4L80e.

I've read some older posts here on guys saying basically the TH400 sucks and the 700R4 is awesome because it has OD... sorry, but that's not true on a heavy duty truck. The TH400 is legendary for a reason: the sheer strength and durability is unmatched in automatics. Give me another transmission that can beat it in strength...I don't think even the HD offerings from Ford or Dodge of the era can hang out with it...the dragster guys have figured this out many decades ago.

The GVWR and CWVWR numbers the units were rated for don't lie.

Just because the lighter duty transmission has OD doesn't make it better than the HD transmission with a direct high gear, again, in a case where you are moving a 6,000 lb truck. Forget about towing something heavy with it...

That's absolutely fair, theres no doubt that they're built to move mountains... i just don't have any mountains that need moved. If i did ever go down to a 700r4 it would be coupled to a 350, and only because either the 454 or the TH400 blew. And for what i'll be doing with it, that combo would be fine.

 

[sewlow]

I'm leaning away from the gear vendors at the 2,000$ price point because i'd still only have 3 gears,

The G/V is a pretty simple unit. Very reliable. Just another planetary.
It divides each gear in 1/2 giving you 1st/1.5, 2nd/2.5, 3rd/3.5 for 6 speeds.
They make 2 models. One for up to 1000hp & the other for over 1000hp. !!!
Good place to find them is in a wrecker that specializes in motorhomes. Class C converted 1 ton vans got 'em. Fords & Chevys. The GMs were 454/T400 powered. I've been quoted prices of $900-$1000.00. That's in Canuck Bucks, too. (U.S. = -20%)
...but with you being 4x4, the G/V install sounds like a real can of worms.

 

[sewlow]

And a shift lever for the G.V.

G/V's are electronically controlled.
Dash mounted lighted rocker switch to engage.
They're either on or off.
Once they're switched on, they work seamlessly, dividing each gear in 1/2, requiring no other driver input.

 

[thegawd]

theres a big ass motorhome parked here, a 78 dodge.... low miles if anyone is interested.... 440.... I want it gone.... It's not mine. I should absolutely take a look under it and see if it has a GV unit. I never thought of that.

Hey Sewlow, we share the same name...

Cheers!

Al