Thanks
4BT GMT400 1997 k1500 6.5
I have a 1997 k1500 6.5 395 turbo diesel w/ 4L80E 4x4 , I am wanting to do a 4BT swap & keep the 4L80E (I am gonna rebuild the tranny it’s at 162k). I plan on doing a 3.73 gear ratio (the truck has a leveling kit and sits on 265/75R17 no plans for a lift or big tires)
1.) What adapter should I use
2.) what shift control would work best
3.) what other parts (other than the 6.0 starter) would I need?
I am a noob to the 4BT and wanting to learn and figure out everything I will need for this swap such as electronics, ECM/PCM, wiring harnesses etc.
I am looking for any and all advice on parts lists and more.
* I will say I am building this as a daily driver to replace the 6.5 that’s in it, no major performance expectations
1.) What adapter should I use
2.) what shift control would work best
3.) what other parts (other than the 6.0 starter) would I need?
I am a noob to the 4BT and wanting to learn and figure out everything I will need for this swap such as electronics, ECM/PCM, wiring harnesses etc.
I am looking for any and all advice on parts lists and more.
* I will say I am building this as a daily driver to replace the 6.5 that’s in it, no major performance expectations
1 - 15 of 15 Posts
4l80e, nor any other GM transmissions are not a success behind Cummins engines. Read on here the many lack of success stories here. 80 and 85’s last for a while, but end up dying because not enough line pressure at the Cummins rpm’s. Might as well get a Chrysler auto the first time, rather do it over upon failure.
Ed in CO
Ed in CO
Ed, we have a couple guys running the 4L80e and so far those are holding up OK. It's the 4L60e that won't hold up for long. The 4L80e and 4L85e are about the only GM brand transmissions that could work. Now for the questions asked. 1. what adapter to use. Several companies offer GM adapters. One is Destroked. Their adapter plate is $795, the flex plate is $695, and you'd need a Ford 6.0 starter which they sell for $199. Summit sells a kit for $1099.99 and it too uses a Ford 6.0 starter which is not in the kit. They also sell a complete kit with starter and torque converter for $1769.94. G Force sells an adapter kit which is $1209 and theirs uses a Ford 6.4 diesel starter. And of course there is the old Cummins GM adapter. Several drawbacks there. #1 is cost. Around $3000 for the adapter and flex plate assembly. #2 is the unit has the transmission or engine in a tilted position. But it does use the stock 4bt starter. LOL. Question #2. What controller. Might check with member Old Roofer. He is using a 4L80e on a 4bt. There are bunch of controllers out there. Question #3, What other parts? Well, first you need to have an engine. May need things like AC mount, power steering pump adapter, exhaust plumbing, engine to frame mounts, etc. As far as wiring, the 4bt basically only needs 2 wires to run. One to activate the starter and one to turn on the injection pump. Some pumps can even be mechanically controlled so you'd only need 1 wire. Need to make a list of things on your vehicle that operate off the engine and see how they will function with the 4bt. Since your vehicle is already a diesel you are way ahead of the game.
Thanks for the information I’m going to keep digging around this forum to learn as much as I can.Ed, we have a couple guys running the 4L80e and so far those are holding up OK. It's the 4L60e that won't hold up for long. The 4L80e and 4L85e are about the only GM brand transmissions that could work. Now for the questions asked. 1. what adapter to use. Several companies offer GM adapters. One is Destroked. Their adapter plate is $795, the flex plate is $695, and you'd need a Ford 6.0 starter which they sell for $199. Summit sells a kit for $1099.99 and it too uses a Ford 6.0 starter which is not in the kit. They also sell a complete kit with starter and torque converter for $1769.94. G Force sells an adapter kit which is $1209 and theirs uses a Ford 6.4 diesel starter. And of course there is the old Cummins GM adapter. Several drawbacks there. #1 is cost. Around $3000 for the adapter and flex plate assembly. #2 is the unit has the transmission or engine in a tilted position. But it does use the stock 4bt starter. LOL. Question #2. What controller. Might check with member Old Roofer. He is using a 4L80e on a 4bt. There are bunch of controllers out there. Question #3, What other parts? Well, first you need to have an engine. May need things like AC mount, power steering pump adapter, exhaust plumbing, engine to frame mounts, etc. As far as wiring, the 4bt basically only needs 2 wires to run. One to activate the starter and one to turn on the injection pump. Some pumps can even be mechanically controlled so you'd only need 1 wire. Need to make a list of things on your vehicle that operate off the engine and see how they will function with the 4bt. Since your vehicle is already a diesel you are way ahead of the game.
Very reason I built my hybrid 48re...4l80e, nor any other GM transmissions are not a success behind Cummins engines. Read on here the many lack of success stories here. 80 and 85’s last for a while, but end up dying because not enough line pressure at the Cummins rpm’s. Might as well get a Chrysler auto the first time, rather do it over upon failure.
Ed in CO
Ed, no question if an automatic was in the plans the Dodge units would be first choice for ease of adapting to the engine. They are engineered for the diesel application. There are Ford units that will work but adapting is more expensive. The GM 4L85e had some limited use on the Duramax but most of those were Allison 1000. On a GM vehicle it's always nice to use their transmission so you don't have to come up with an adapter for the transfer case.
Since he is going to rebuild the transmission anyway, it can be built with many high performance parts that will handle the torque. Sonnax transmissions is a great place for these parts. They have parts that will even make a 4L60 live behind a Cummins. Not cheap, though.
Forgot, GM performance parts also has high performance transmissions such as the 4L75e and others. They were never put into production automobiles but can be bought from GM. Again, not cheap.
Dodge 47 or 48 RE can be built to handle sustained torque levels way beyond what most every GM trans except for the Allison's.
I had a big bucks built 4L80, I dared not use, because of its weakness related to massive low rpm torque behind a Cummins...
I had a big bucks built 4L80, I dared not use, because of its weakness related to massive low rpm torque behind a Cummins...
Here is an image of mating a 47/48RE to a NP241c, notice one mounting hole needs too be elongated, and the t-case input needs to be long enough by the thickness of the adapter to mate the two components.Ed, no question if an automatic was in the plans the Dodge units would be first choice for ease of adapting to the engine. They are engineered for the diesel application. There are Ford units that will work but adapting is more expensive. The GM 4L85e had some limited use on the Duramax but most of those were Allison 1000. On a GM vehicle it's always nice to use their transmission so you don't have to come up with an adapter for the transfer case.
The main issue on most automatics is not the amount of HP or torque, but when that torque comes on. The pump in the transmission builds pressure to feed the clutch assembly as RPM rises. Most normal engines hit their peak torque north of 2000 RPM. The early Duramax had 310 HP @ 2800 RPM and 520 lb ft of torque @ 1800 RPM. The transmission used early one was the 4L85e which was set up for it. This was probably the one called the Supermatic 4L85e. It had an additional clutch plate and revised valve body for more pressure. That one is is rated at 685 lb ft of torque and can be purchased from your local GM dealer for around $5000. That doesn't include the torque converter. I don't believe an Allison 1000 would be that expensive.
Would converting a 4L80 to a full manual valve body, giving the trans. constant full line pressure, help it to live behind a 4BT?
The 4L80/85e performance pack from Sonnax increases line pressure. They have different valve bodies as well. Extra clutch plate, hardened reaction shell, many other parts to make them super strong. That’s how I will build mine. If I don’t just buy one outright from GM. As a retiree, I get them at cost.
I like that Dodge has a transmission pump gear for diesel, pumping more fluid volume at lower RPM's.The main issue on most automatics is not the amount of HP or torque, but when that torque comes on. The pump in the transmission builds pressure to feed the clutch assembly as RMP rises. Most normal engines hit their peak torque north of 2000 RPM. The early Duramax had 310 HP @ 2800 RPM and 520 lb ft of torque @ 1800 RPM. The transmission used early one was the 4L85e which was set up for it. This was probably the one called the Supermatic 4L85e. It had an additional clutch plate and revised valve body for more pressure. That one is is rated at 685 lb ft of torque and can be purchased from your local GM dealer for around $5000. That doesn't include the torque converter. I don't believe an Allison 1000 would be that expensive.
1 - 15 of 15 Posts
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