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which trans th400 or 4l80e?

jp0863

jp0863

1/2 ton status
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gonna build a suburban now since the family is bigger. should i get one with the th400 or 4l80e? gonna be used mostly for moderate wheeling and i'll be running 35's with 4.56 gears. what would my rpm be at say 55 mph with each trans? thanks
 
If you're getting one with a 4l80e, you're getting a NBS Burb. Lift kits will cost about triple for those compared to the old-school Burbs. :D

And if you get a 4l80e for an old-school Burb, the buy-in AND the rebuilds will also cost you about triple compared to a TH400.... so..... you need to go to 4lo.com, use their calculators to figure out your rpm's etc etc, make an educated guess at how much gas the 4l80e will save you, and then compare--- how much gas can you buy with the money you'd have to pay for the 4l80e???

For me, that worked out to about.... $2400 (for the extra cost of the trans, the rebuild, and the standalone computer), which equals about 800gal of gas, which equals about a years worth of driving w/a TH400. :D
 
looking at a 1991 vs 1990 3/4 ton... old body style. i'll check 4lo.com. not worried too much about the fuel difference cuz it's nominal for what i would do and how often i would drive it ( i put 3000 miles on my k5 in 5 years) needless to say i need to wheel more, but my youngens are just now getting old enough to go with me. my main concern was reving the engine too high when i do go out of town with it.
 
This is a no brainer. The 4l80E is far superior to the TH400. The 4l80E is basically a beefed up TH400 with OD.

Your rpm's @ 55 mph with 35's, 4.56's and a TH400 would be roughly 2407 and with a 4l80E you'd be looking at roughly 1805
 
Yeah wow I can't believe all that rambling up above about triple the cost this and that. go with a 4l80e. 91 sub is what you want. I love mine. and no lifts are not expensive.
 
'Cept for paying for it.

I love the 4L80E too, but it's bank.

TCI wants $3053 for theirs
Bowtie Overdrives wants $2200 for their version.

Add a sweet CompuShift controller for another $1300 (with LCD display).... yep, bank. :yikes:


This economy isn't helping either. Now I'm too scared to spend my cash to do it... with my luck as soon as the tranny arrived I'd lose my job.



:usaflag:
 
He's buying a whole truck. From what I've seen, the price of the 4L80E isn't buoying the price of the '91's. You can get the whole truck (in good shape) cheaper than you can adapt a 4L80E to an earlier truck!
 
Buddy just bought one for that price too, and it's a NICE truck. I'd rather swap all the '91 Injection stuff over than go aftermarket on a 4L80E setup.
 
mine was 2200, never knew the trans was so much. that a lot of coin.
 
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I don't think I'd ever not have OD on a rig that saw the highway... it's so nice. My 'burb had the trans replaced with a Goodwrench crate 4L80E at the dealer in late 1998, at no cost to the original owner. Truck only has 111K on it, with only 58K on the trans.
 
The previous owner took the 700R4 out of my 88 Sub and swapped in a TH350. It's a good tranny, but a well built OD tranny would be nice to have. My highway revs aren't that high with 3.73 gears and 31x10.50's on it, (for now anyway), but I'd sure like the option of bringing them down a few hundred rpm's for a couple more MPG's.

My advise is to go for the OD tranny. I doubt you'll be sorry.
 
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