Transmission swap - OD

[crashz]

My dump truck will be down for the forseeable future, as I suspect that the injection pump has given up the ghost. While I won't enjoy it, it will give me time to start working on the back of the frame, dump body, hoist and a bunch of other things.

One of those is the transmission. The truck had an orginal th400 which was swapped out for a junkyard th400 after reverse blew out by the PO. The new 400 must be from a gas truck, as it revs like crazy to move, and shifts too late. In fact, I'm positve it came form a gas truck.

Now many years ago, my 83 had a 700R4. It was a plow truck for all its life with no real problems other than a trans guys convinced my father that the 700 was junk.

Fast forward to now. I was thinking rather than fix my current 400, what about buidling a good 700 for my truck? The truck will see extended highway use once its running reliably. OD will allow it to travel highway speeds and save a bit of fuel.

Now I know people have had these break behind a 305, but in reality the 6.2 diesel is nearly in the same power range. The big issue is weight. Can the little 700 handle a 10K lb rig with occasional towing? I've seen it work well in a 3/4 ton for plowing and towing, but a 1 ton dump?

A goal with this truck is to lighten it up a lot, so that the empty weight will be in the 5-6000 lb range. Thats a lot of fat to cut. The smaller, lighter 700 with a NP 208, single peice drive shafts, rear disk brakes and an aluminum body may get me there. This would let me haul two cubic yards roughly, without being overweight.

All opinions and comments welcome. Any addtional ideas of weight savings, transmission choices etc welcome as well.

[mrolds88]

Personally I don't know how well a 700 will hold up, without a bunch of work. Just my opinion. And I had a 700 blow up on me behind a 4.3. Anyway, I would think a 4L80e would be a better choice. Plus, if you get one from a 90-93 diesel, they had their own controller.

[79Betty]

Agree. If you're gonna upgrade do it so you don't have to worry about it. It's like a 400 with overdrive. Also not hard as A LOT of people have updated to the 4L80. It's a solid good transmission if taken care of.

[nekkidhillbilly]

4L80e is all id have in a hd truck

[D13]

TH400 sounds like wrong converter and failure of the vac system or governer. Probably someone put a converter and a kit in it for their 9000 rpm SBC, versus the needs of a 3200 RMP diesel. Remeber too that the diesel vac pump feeds the trans modulator via the variable valve on the IP. ALl those need to be checked. But the high rev to start definitely sounds like the wrong converter.

Auto OD on a dump truck, 4L80E is the only way to go, or a Gear Vendors OD unit - roughly the same price by time you sort out the TH400.

[MalibuSSwagon]

There is a reason GM put 700R4 behind 6.2 in half-tons and TH400 in the 1 ton, the weight would break a stock 700R4 in half. There are built 700R4's out there that can handle high hp applications. I would suggest contacting Bowtie Overdrives and other reputable 700R4 transmission builders for their suggestions, their business is building these transmissions so they should have an idea of what they can handle.

[crashz]

I had briefly thought about a 4L80E and a NV4500, but they seem to be gold plated around here. All the local yards and parts places want big money, if they have any to sell.

My other issue withthe 4L80E is the controller, which seems to be expensive. I realize there is a specific year or two with a non electronic 4L80 and passenger side drop NP205 that I should be looking for, but they are even tougher to find. I guess I should stop complaining, as I'll have all winter to look

The weight benefits are also out with a 4L80 or NV4500. Those are some beefy components. Maybe there is a reason

I'll contact a few specialty shops too. There will have to be a balance between strength, weight and economics here. A $5,000 700R4 is probably possible, but a total waste of money. However, if a reasonable trans could be built to accept the NP 208 and single peice drive shafts from my 83 (that truck will get an entirely different drivetrain), then I could do it for a low price and get what I'm looking for.

Any other thoughts? What about manual OD transmissions other than the NV4500? I have a parts truck now with a 4.3L V6 and 5 speed (I think its a NV3500?) but from what little I know, its a pretty weak transmission. Its also 2wd, so it would need a different tail shaft.

[MalibuSSwagon]

NV3500 is fairly weak, and the tailshaft is the back half of the case. I'd get one for my C10, but I was warned that towing would break it.

I do prefer a manual trans myself, but your right about the cost around here. JY want $800 for a 1993 NV4500 2WD! For a used transmission with 90-200k miles, come on! When I was in Colorado this summer I tripped over a 2WD NV4500 sitting in a field of transmissions, the place wanted $200! It was tempting but considering shipping home and the fact it was sitting outside, even in the Colorado high desert, it lost it's appeal.

Check this out: http://www.bowtieoverdrives.com/cata...SUBCAT&CATID=B

The first two are 4WD transmissions.

[nekkidhillbilly]

well 2k is what you looking at on any swap really.

[bilfman]

I did a 4l80e swap in my 79. Used the $600 TCI controller was a way easy swap. I have that swap on this site. Just on my iPod a don't know how to link it. I was lucky to find the 1991 4l80e/np205 combo. The controller and electronics were simple. So don't let that hold you back.

[crashz]

I think you have changed my mind about the 4L80e. Just have to hunt one down with the proper year. I was thinking that the controller was around $1200, then a used trans. So I was thinking cost was going to be really high.

So a 1991 4L80e and 205 combo is what I need to look for.

Thanks for your help guys!

[Rogier]

I used the USShift controller for my 4l80e. I did nothing to connect it, never touched any software and it works really great.

[nekkidhillbilly]

cant u use any 4wd one?

[bilfman]

Here is my build swap

http://67-72chevytrucks.com/vboard/s...d.php?t=537481

[nekkidhillbilly]

you can use any 4wd 4l80e just need the adapter ring from a stock 91 truck or you can buy them aftermarket. idk how much it will cost other than that the trans and the ecm is all else you need.