I own a 1990 chevy c2500 with a 3 speed transmission. I want to put a 4 speed into it. What trans will fit with the least modifications needed. Not looking to spend a lot of do major work just want better highway travel.

 

700r4 is the only 4 speed auto that doesn't require a computer. It's alot weaker trans than your th400. Unless you want to go manual, the other options are going to be expensive and difficult.

 

[QUOTE=burnhedge;440769]700r4 is the only 4 speed auto that doesn't require a computer. It's alot weaker trans than your th400. Unless you want to go manual, the other options are going to be expensive and difficult.[/QUOT

Thanks for your reply. I was hoping that was not the case. I haul quite a load for my little truck. Generator welder and tools never leave the rig. I have swapped a 700r4 in an s10 a time or two and that was much less of a truck. I can turn a wrench but I don't really have the knowledge or experience to do a swap to manual.

 

Most 1500s had 700r4s so it's not all that weak, but if you tow heavy your rolling the dice.

I've heard the 4l80e behind the early mechanical diesels have a stand alone computer if you happen across a parts truck with that setup. Aftermarket controllers are available but with a big price tag.

Manual swaps are really easy on these trucks if you have a parts truck to get everything from. Plus you can have a 4 or 5 speed.

 

the 700r4 is a weak trans if abused.
the 4l80e out of a 92 and 93 with the 6.5 used a standalone and 1991 was still the 6.2.
my 91 v3500 came with the 4l80e and 5.7 tbi. i swapped out the 5.7 for a cummins now i have a "black box" for the trans. pretty much makes the automatic trans a manual and lefts you shift with the shifter. isnt too bad but can be a pain and i wont let anyone else drive it except for one friend that i know can remember to shift the "automatic" trans.

like burn said i would think about a nv4500 swap before adding an auto unless you have the auto trans laying around.......but then the price of the parts/trans will out weight the gas millage you'll save no matter which way you go unless you need to replace a burnt trans anyway