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cummins swap, adapter or transmission?

oneofthefewbmx

oneofthefewbmx

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guys...im fixin to put a cummins in my truck here in the next few days and im not sure if it would be cost effective to spend several hundred dollars on an adapter for my th400, or just get an auto dodge tranny and put my 205 on the back of it...

either way, im having a hard time rearching both, can you guys hook me up with places to purchase the adapter (ive already called enterprise and diesel depot)

and if not that, which dodge tranny would i have to use to put my 205 behind it (preferrably overdrive) thank you guys in advance!!
 
ebay or crewcab59. I got mine off ebay with a trans.

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I helped a buddy do this swap a few years back. I contacted him last night and asked him about it. He bought a bell housing adapter from cummins for a mid 80's chevy bread van with a th400 tranny. Costs about $1200 tho. You would also need a special starter. We found one local for $300, but you might be able to go to a starter specialist and tell them what you want. If you use this adapter then something will sit at an angle depending on how you set it up. Speaking for expeiriance, I would stay away from a Dodge tranny. We put a TCI built tranny behind his cummins. Let me know if you need a starter.
 
ya the 4bt cummins is ether stick or th400 . just find the setup from that. also it will need the tranny pan to go with it.
 
Do you think you could put a built (TCI) 700r4 behind a 4bt cummins?
I have been thinking about this for my 84
 
Even with a full flow pump and other internal mods the 4th gear piston still lacks the surface area to hold high torque levels.
 
trev1981 said:
Do you think you could put a built (TCI) 700r4 behind a 4bt cummins?
I have been thinking about this for my 84
Click to expand...

I wouldn't see why not. Should be the same bell housing as a 400, which would mean same adapter. The th400 adapter that I mentioned above wound up on a TCI built 350.
 
wow thanks for the info guys...i dint realize i needed a special starter and pan...hmm....i thnk i may go with the a518, i know its crappy though. ill get it built after it blows up....do you guys happen to know the output shaft spline count on an a518? i know they came with 205s on them (which is what im going to use) but im sure its a different splink cound than my chevys...thanks again guys
 
You dont need a special transmission pan for it to work. The full cast pan like I have on mine is one piece with the dust cover. It replaces the inspection cover and bolts to the flywheel housing giving you 360* of retention to hold more torque. You can use a regular pan with the stock inspection cover and it will work.
 
yea, ive seen that picture before while doin some research...is that just a regular cummins starter? also how thick is the spacer and ring that are on the flexplate? im wondering if i can somehow make the regular flywheel (becase it is thick and already bolted to the cummins) work somehow, mabey just drill new holes for the TC. what do you think?
 
I've never heard of a special pan..........

its a regular cummins flywheel with a steel strip to bolt the converter too........

I believe thats a regular cummins starter, both my cummins have starters that look just like that........
 
Forget a TH400, it's a non locking 3 spd...... Thats like building a crazy cool K5 on Rockwells, and then sticking some 33" A/T tires on it.

Go with a 518 or 47RH Dodge trans. Both are basically identical, minus a few updates and a new name. They have a reputation for being junk because it's silly easy to make a 12v Cummins that was always found in front of them make 800+ft lbs of torque. Put a TH400 in that spot and see how well it outlasts a 518....

You want a lockup 4 spd auto if at all possible. You have to remember the smaller RPM and torque range of the new motor. Plus, if you are making some good hi power, nothing hits harder than hitting lockup and watching the speedo jump up that much faster.
 
hmm....that makes sense....wow, i just changed my mind like 4 times in an hour or so...ok, so im stickin with the a518....can anyone hook me up with a spline count on the output shaft? and im assuming its the round bolt pattern for the 205 correct? does anyone know where i can get the stock a518 to np205 adapter? junkyard is pretty much useless around here....thank again....
 
trev1981 said:
Do you think you could put a built (TCI) 700r4 behind a 4bt cummins?
I have been thinking about this for my 84
Click to expand...

The 700 will easily handle the HP and torque of a 4BT. The thing I would worry about is the 4BT's output torque fluctuations, which would probably be hard on the 700's sprag, planetaries, and reaction shell. This is just a guess on my part - I have no personal experience to back this up. If I tried it I would definitely use the best upgraded internal parts available.
 
MaxPF said:
The 700 will easily handle the HP and torque of a 4BT. The thing I would worry about is the 4BT's output torque fluctuations, which would probably be hard on the 700's sprag, planetaries, and reaction shell. This is just a guess on my part - I have no personal experience to back this up. If I tried it I would definitely use the best upgraded internal parts available.
Click to expand...

What do you mean by torque fluctuations? and in the other thread you said you're conserned about vibrations, can you elaborate on that some. I'm finding it hard to grasp what you find to be a problem. Thanks.
 
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