Automatic transmission upgrade

[machmeter62]

Thanks, I will check-out that site;those RPM # are favorable.

 

[sld]

Check out the gear vendors unit.

It will make your 3 speed a 6 speed and is probably a cheaper way to go.

 

[machmeter62]

Gentlemen;
Here is what I have discovered for both price and performance. After reviewing 'Gear Vendor's" site, they may offer more speeds, with the over/under gearing, that fine tunes ones performance; but the initial cost and installation costs ($750), is too pricey, well over $3000 total for me,

I think "Raw Dodge" has the answer for my budget, and the installation is less complex, that may not even need the crossmember modified, after taking all the measurements today. I can get the (GM 4L-80E, or 80). for $1537...no sales tax...shipped free to California. This tranny, shipped from AZ, is a re-man with 2 yr/24,000 miles warranty that can handle the RAT-454 engine with > 500hp! I still might get more local opinions from local repair shops for the installation work.

I was also told, it's this GM transmission that is installed in the RollsRoyce?
LEE

 

[machmeter62]

Gentlemen;
Here is what I have discovered for both price and performance. After reviewing 'Gear Vendor's" site, they may offer more speeds, with the over/under gearing, that fine tunes ones performance; but the initial cost and installation costs ($750), is too pricey, well over $3000 total for me,

I think "Raw Dodge" has the answer for my budget, and the installation is less complex, that may not even need the crossmember modified, after taking all the measurements today. I can get the (GM 4L-80E, or 80). for $1537...no sales tax...shipped free to California. This tranny, shipped from AZ, is a re-man with 2 yr/24,000 miles warranty that can handle the RAT-454 engine with > 500hp! I still might get more local opinions from local repair shops for the installation work.

I was also told, it's this GM transmission that is installed in the RollsRoyce?
LEE

Who makes the separate transmission controller for GM's 4L-80E trans?

 

[Stimw]

I have been researching this too because I have a 1989 Southwind motorhome in very good condition and the change over would really help it.
Check 4L80E prices on ebay, there are some good prices and their feedback should help you decide. Check craigslist.org in your area, I have seen them for under $500. locally. The newer 4L80E's are said to be stronger, I think it is 1996 and up. New ones have oil cooler connection lines wider apart on side of trans. 4L80E uses a lot of the same parts as a Turbo 400 so it is a good trans.
You need a controller, google 4L80E controller and you will find suppliers. Some are computer tuneable. You also need a speedo converter from electronic to manual read. There are two kinds of these, tail housing change over (keep mechanical) or elec to manual.
The gear vendors seem like a good product but pricy and you have to shorten driveshaft and make/buy mounting bracket.

 

[Bruce-4310TX]

if you have a turbo 400 now, then a 4L80 will bolt right in i believe its still the same length. I doubt if you have a turbo 350 and 700 r4 did not come out till 1984. shop around for the controllers lots of places carry them even Jegs and Summit. CK out some Hot-Rod forums with a little Googling you should find out all the parts needed to do this swap. If you or someone you know has the savvy to rebuild a automatic go get a good core junk-yard swap meet and get a Kit from Monster Transmission they have every thing you need. They are not hard too rebuild and rebuild manuals are cheap and available on E-bay.I used a few of there kits very complete theyl set you up at a reasonable price. Also if you change the rear Gears to 3.73 that will help and still give a great tow Rating and you could get rid of that 400 s/b and put in 383 S/B OR GM CRATE HT383 more power and better mileage. Recoup some money by selling that 400.

 

[carpenter383]

If you're dead set on spending the money on an overdrive trans, then the 4l80e is a nice heavy duty trans. It's a th400 with overdrive. (your van definately came stock with a th 400) I'm pretty sure a 4l80e is a couple inches longer than a th400, so the driveshaft will need shortened, the cross member will probably need moved too.
It wouldn't be worth changing to 3.73's IMO I wouldn't change gears unless you go a significant ammount (like from 4.10's to 3.55's or higher)
The 400 sb was only made for 10 yrs. ending in 1980 so they're getting scarce and are worth some money, (4-500ish for a decent longblock) yours is a 2 bolt main which is a little less desirable to some people. A 400 sbc has the same 3-3/4 stroke crank as a 383 stroker would (which is where the tourque comes from) but it's a smog motor and prolly don't have much power. A decent 383 with a mild cam (rv) would be more powerfull for sure, but if you're not towing it wouldn't be very justifiable in my oppinoin.
Your biggest bang for the buck (for lower cruising rpm's) would be to keep the th400 and put higher gears in the rear end. It'll take a long time to make up for the cost of a 4l80e swap.

 

[machmeter62]

If you're dead set on spending the money on an overdrive trans, then the 4l80e is a nice heavy duty trans. It's a th400 with overdrive. (your van definately came stock with a th 400) I'm pretty sure a 4l80e is a couple inches longer than a th400, so the driveshaft will need shortened, the cross member will probably need moved too.
It wouldn't be worth changing to 3.73's IMO I wouldn't change gears unless you go a significant ammount (like from 4.10's to 3.55's or higher)
The 400 sb was only made for 10 yrs. ending in 1980 so they're getting scarce and are worth some money, (4-500ish for a decent longblock) yours is a 2 bolt main which is a little less desirable to some people. A 400 sbc has the same 3-3/4 stroke crank as a 383 stroker would (which is where the tourque comes from) but it's a smog motor and prolly don't have much power. A decent 383 with a mild cam (rv) would be more powerfull for sure, but if you're not towing it wouldn't be very justifiable in my oppinoin.
Your biggest bang for the buck (for lower cruising rpm's) would be to keep the th400 and put higher gears in the rear end. It'll take a long time to make up for the cost of a 4l80e swap.

I crawled all over the transmission, and gave up to identify it. I called the Chev Dealer, and he put me in touch with a tranny "guru!" He said, climb under again and tell me the shape of the trans pan, it's either shaped "oval, or squarish" ...the Th-350 is the square one, and the oval pan is for the TH-400. So I have a TH-350 in my '78 van with the squarish one. I purchased it new in the spring of '78.

 

[carpenter383]

I crawled all over the transmission, and gave up to identify it. I called the Chev Dealer, and he put me in touch with a tranny "guru!" He said, climb under again and tell me the shape of the trans pan, it's either shaped "oval, or squarish" ...the Th-350 is the square one, and the oval pan is for the TH-400. So I have a TH-350 in my '78 van with the squarish one. I purchased it new in the spring of '78.

I've never saw a th350 in a 1 ton. Does your trans have a kick down cable, or a wire with a solenoid (at the carb) going from the trans to the carburetor? If it's a cable it's a th350 if it's a wire it's a th400

 

[MossRoad]

Why don't you go with a 700R? You get O.D. and don't need a controller. Just asking.