1992 Dodge D250 Duramax

[1stgensleeper]

Thanks so much for the quick reply! I am running the stiffer 7226s moog springs under mine. Do you know what offset and backspacing was on those wheels? Also did they rub anywhere?

Yup those are the springs I'm running. I do not know the offset or back spacing, just picked them up on Craigslist and put them on. I had to cut part of the fender in front of the tire off and hammer a few places in for extra space at full rack (steering) travel. A set of new mud grapplers might rub because the huge tread blocks but these bald ones didn't at all. Something like a BFG All Terrain wouldn't rub at all. It looked sick with those big meats stuffed in there.:thumb:

 

[1stgensleeper]

After seeing some different info on here and looking at prices, I've been thinking about using a turbo 400 trans with overdrive or a 700r4 in my truck. The price for a built gm tranny is substantially less than a 47rh is. Even though I already have a pretty stout 47rh in my truck the adapter plate alone might be around $800-$900 to be able to mate it to the Dmax.

Do you guys have any input on what to do here? The truck is a daily driver that I drag race with. I don't cruise on the freeway very much but if I could still be able to do so and get good fuel economy I would be very happy. Thanks for any input.

 

[coker6303]

JoshH has a 4L85E that rips behind his 10sec van. He can give a little insight on that at least. :thumb:

 

[dslhtrdr]

After seeing some different info on here and looking at prices, I've been thinking about using a turbo 400 trans with overdrive or a 700r4 in my truck. The price for a built gm tranny is substantially less than a 47rh is. Even though I already have a pretty stout 47rh in my truck the adapter plate alone might be around $800-$900 to be able to mate it to the Dmax.

Do you guys have any input on what to do here? The truck is a daily driver that I drag race with. I don't cruise on the freeway very much but if I could still be able to do so and get good fuel economy I would be very happy. Thanks for any input.

Buy the adapter plate and be done with it. You will need to either get the duraflite converter from suncoast or see if they can cut off the cover on your current one and weld on the Allison front cover to bolt to the duramax flexplate. Based on my experience with the 47rh behind my LBZ, I would never run a turbo 400 or 700r4.

 

[1stgensleeper]

Buy the adapter plate and be done with it. You will need to either get the duraflite converter from suncoast or see if they can cut off the cover on your current one and weld on the Allison front cover to bolt to the duramax flexplate. Based on my experience with the 47rh behind my LBZ, I would never run a turbo 400 or 700r4.

Sounds like you really like the 47rh behind the duramax, any specific reasons why? My plan was to cut the cover off of my high stall Goerend converter and put a chevy cover on it. My buddy has a cnc plasma table he's getting dialed in and he said he might be able to cut an adapter plate out. We'll have to see.

 

[dslhtrdr]

Sounds like you really like the 47rh behind the duramax, any specific reasons why? My plan was to cut the cover off of my high stall Goerend converter and put a chevy cover on it. My buddy has a cnc plasma table he's getting dialed in and he said he might be able to cut an adapter plate out. We'll have to see.

I just like them. I have one in my 12v and have never had a serious problem with it and I've beat on it quite a bit. The Camaro has a reverse manual valve body and a trans brake.

Common sense tells me that if you have a tranny that already works well, you should keep it. It might take some extra coin to adapt it, but you're going to have to spend more money on a new tranny and getting it built anyway. If you have the ability to make your own adapter plate and modify your converter, I say go for it.

 

[JoshH]

I've been really happy with the 4L85E I'm running in the dumpster. It has made a bunch of 11 second passes and 1 10 second pass over the past year and a half with no failures. My race weight is probably close to what yours will be (I'm 5320 with me in the driver's seat). The nice thing about the 4L85 is that it bolts right up to the Duramax and has a lockup converter and overdrive which is something you can't say for any other option out there without spending a lot of money. I would definitely not do a 700R4. Those things are barely up to the task of a mildly built small block.

 

[dslhtrdr]

^^^ The only GM tranny I would consider is what Josh is using.

I'm not rooting against the GM trans, I'm just saying you could save yourself some labor by sticking with what you already have. The Duramax is shorter than a Cummins so you could still use your factory tranny mount and not have the motor sticking into your radiator.

 

[1stgensleeper]

That's some good info guys. I think I'll try and stick with the 47rh then. I do plan to use a full manual vb and ratchet shifter too. It's a work in progress but I'm excited to see what it'll do when it's done.

 

[1stgensleeper]

Ok, so my plans have kinda hit a bump in the road but it's a good one.

I have a buddy who told me about a duramax engine that he knew of for sale. I got ahold of this guy and I discovered it's a 2008 engine with 119,000 miles out of a van and it comes with the 4l80e or 4l85e transmission (not sure which one it exactly is). He's asking $3800 for the complete engine with all the wiring, ECM, Transmission, radiator, and intercooler.

My question is pretty simple: go for it or not?

If I do buy it I will run it with the stock turbo and injectors in my truck until I can save up to upgrade. I think it would be fun to see how far I can get with a tuned only engine. I would also save a lot of money by using the gm tranny because I don't have to buy an adapter plate to use the dodge tranny. Let me hear what you guys think.

 

[malibu795]

I've been really happy with the 4L85E I'm running in the dumpster. It has made a bunch of 11 second passes and 1 10 second pass over the past year and a half with no failures. My race weight is probably close to what yours will be (I'm 5320 with me in the driver's seat). The nice thing about the 4L85 is that it bolts right up to the Duramax and has a lockup converter and overdrive which is something you can't say for any other option out there without spending a lot of money. I would definitely not do a 700R4. Those things are barely up to the task of a mildly built small block.

AFAIK LB7 wont work with the T42 TCM to run the 4l85..
though the standalone systems can be setup to run of a TPS signal


nice build:thumb:

 

[1stgensleeper]

If I stick with the lb7 I'll run a 47rh with a manual vb. The problem is the adapter plate and a custom manual vb will be a lot of money. That's why I'm considering buying this '08 van engine with a 4l80e behind it.

 

[malibu795]

If I stick with the lb7 I'll run a 47rh with a manual vb. The problem is the adapter plate and a custom manual vb will be a lot of money. That's why I'm considering buying this '08 van engine with a 4l80e behind it.

08(lmm) is a 6l90
06-07 (LBZ that is rpo as a LLY) is 4l85

LB7+4L85 with manual VB

 

[1stgensleeper]

08(lmm) is a 6l90
06-07 (LBZ that is rpo as a LLY) is 4l85

LB7+4L85 with manual VB

So what would you do if you were in my shoes?

 

[MAXX IT OUT]

The adapter plate is about 1200 bucks to put the 47rh behind the duramax. I would go the 47rh route, since you already have a built on vs buying a 4l85e, which I have had no luck finding then having it built. That is going cost more the 1200 bucks. So I would run with your current transmission.

 

[1stgensleeper]

What about the fact that LMM's have a better injector design than the lb7's and a better computer system that can allow it to turn more RPM's compared to an lb7? Wouldn't that make you lean forward getting the LMM and 6l90e? The truck will be a daily driver so I see a 6 speed helping out a lot in the mpg department, even though good mpg's weren't the original plan, having them would be a definite plus.

 

[malibu795]

So what would you do if you were in my shoes?

The adapter plate is about 1200 bucks to put the 47rh behind the duramax. I would go the 47rh route, since you already have a built on vs buying a 4l85e, which I have had no luck finding then having it built. That is going cost more the 1200 bucks. So I would run with your current transmission.

buying a 4l85 is ~400-1300.00 pending year mileage (98 and newer is prefered).... then your going to have to build it..you will be easily putting another easy 3-4k into building the 4l85 parts wise.
13 is last year they are mass produced..

if the 47 is already built.. you are money ahead just getting the conversion stuff, and running that route.. and the quick route

another option sell the 47 and go 4l85 and build it

personal pref.. i'd try to keep the engine/tranny in the same brand..

 

[malibu795]

What about the fact that LMM's have a better injector design than the lb7's and a better computer system that can allow it to turn more RPM's compared to an lb7? Wouldn't that make you lean forward getting the LMM and 6l90e? The truck will be a daily driver so I see a 6 speed helping out a lot in the mpg department, even though good mpg's weren't the original plan, having them would be a definite plus.

LMM all around is better than the LB7.
the 6l90 has longer legs (taller ODs) than the 4l85 and a shorter 1st.
aftermarket is just now getting stuff to last in them.. R&D is about done for the most part is down to you need ABC stuff to handle D power..
33" tires 3.73 gears and .75 OD is ~2000rpm @ 70 with the 4l85 and ~1750 in 6th with the 6l90, OD being .66

the 6l90 in a clutch/clutch tranny so no manual VB like the 4l85/47rh can be had.

 

[1stgensleeper]

If I were to keep it at 500-600hp max, would the 6l90e be ok after a full rebuild?

 

[dslhtrdr]

Buy the lmm, sell the lb7, and get the adapter plate. I don't think you have to have a manual valve body, you can find a way to attach the tv cable to the throttle pedal if necessary. You will be money ahead if you keep the 47rh.