I have a 1996 Chevy K1500 I'm going to do a 4BT swap in. I plan on switching out the 4L60E for a 4L80E. I already have a 6inch suspension lift so I should have room to fit it under the hood. I picked up the 4BT a couple months ago and decided to tear into it and see what it looked like. I found the camshaft was damaged, the #1 piston scuffed the cylinder wall, and the #3 piston second ring was broken. The engine has numbers stamped on the caps so it's been torn into before. I am sending the 4BT and a 12V to the machine shop next Wednesday. Here is what the lobes on the camshaft look like.





It's a good thing I decided the check the engine out before putting it in my truck.

 

#1 Piston

 

What trans adapter did your 4BT come with?

I was very unimpressed with a TH400 behind my 6.2L chev. (In a Suburban w/4.10 ratio) It was a slug, and didn't seem to put any power to the ground. The 4L80E is simply the electronic overdrive version of the same trans.

A few years later I ended up powerstrokes... and F350 (5spd) and E350 (auto) which re-confirmed my distaste for automatics with diesels.

IMO, a 5spd would be ideal, or in the very least the more efficient 4L60E/TH700 class trans. The TH700 has the benefit of not needing any electronics to operate.

 

Never had a problem with my 4l80's, they don't bark tires when they shift but they are extremely tough. Biggest draw back is they have a junk torque converter from the factory, get a low stall triple disk from someone like yank that makes a good product

 

Not discrediting the durability of the transmission.

The 4BT has somewhere in the range of 90-130hp and the TH400/4L80E series trans will eat up a big chunk of that. The 6.2L in my Suburban was a different animal after a SM465 swap and 3.21 gears. It suddenly had power and economy.

 

My 4BT was out of a bread van so it's rated at 105 HP. I plan on turning it up, I'm not sure how much yet. This builds focus is on mileage so I don't want to go too crazy on the power. My 4BT was mated to a Chevy 4 speed manual, and I got the adapters with it. I would prefer a manual, but this truck is already an auto with a push button transfercase shifter so my floor in the middle has nothing sticking up, and I want to keep it that way.

 

Might be a good idea to read up on 4BT conversions over over at:
Cummins 4BT & Diesel Conversions Forums


This guy used a TH700... but would have gone 6BT if he did it again.
93' Suburban Cummins 4BT swap - Diesel Place : Chevrolet and GMC Diesel Truck Forums


Mention here of the Dodge 47RH having better gear ratios than the TH700.
Real world mileage 4BT 1/2ton - Pirate4x4.Com : 4x4 and Off-Road Forum

 

Nothing says economical like a 6 inch lift and mud tires hahaha.

The truck will be slower than a stock 6.5 so a 6 bt would be a good idea and then use the 4l80 for its durability.

I got 22mpg in my 95 k1500 with a 6.5 and 4l80 but it was stock suspension wise

 

A 47RH was my plan B trans. Ya I know a lifted truck isn't very economical but I'm ready for anything above 10 MPG. I'd rather tune this engine for mileage because I'm building a 1995 Chevy 4-door for towing/power.

 

Nice perk with the 47RH is OD is the extra tall OD at .69.

I see it as the ideal auto trans because you can ditch electronics completely now that your engine is too. And its already made to fit together.