So, couple days ago I picked up a '91 d-250 diesel automatic, runs awesome however the overdrive doesnt engage. There is a button on the dash to turn it on and off, the "od off" light comes on when you push the button, but the OD always stays off wether the button is lit up or not. It's 4x4, has a few miles on it, not quite sure exactly, says 88,000, but has a brand new speedo sending unit. Any and all help is appreciated!

 

the trannies on these trucks are fully hydrolic, my best guess would be to take it to a good tranny shop and have it flushed. you might have some trash stopping up a solenoid.

when you want to turn the power up on that thing just let me know

 

i dropped it off this morning actually. He's gonna scann it first, hopefully I'll find out something soon. He also said the weak link in these trannies (a518) is the torque converter. This true? i have no doubts with as much torque as the cummins puts out. What do you suggest to do for power? Abvioulsy i'll be purchasing a k&n asap. My dad has a 99 24 valve with a banks power pack, runs well but i dont really wanna spend that much money. I'd really like to do the propane injection, sounds like the best money spent. What do you think??

 

well. . .the thing with propane injection is that you burn about the same amount of propane that you do for diesel. so if you can source propane for cheaper than diesel then your at step one. step two is that the propane doesnt start flowing untill you hit enough boost. not enough pressure and you risk damaging the engine.

now, if you dont want to spend much money this is the route I would go.

dump the exhaust and bolt up a full 4 inch exhaust, this will be the largest improvement, plus it will help reduce EGT's. #2 read up as much as you can about your VE pump. with only a few adjustments the increase in power is VERY impressive. but what the old engines were know for was not horsepower like mine, but the massive torque. Ive seen 270hp and 750tq at the rear wheels

I wouldnt worry too much about the tranny just yet, but when things start to get a bit dicy look into either getting a stock 48RE that has had a little valve body work done. or hit up DTT or ATS. both do very good tranny work

 

oh, one more thing, do some reading about the killer dowel pin, that is also something you might need to look at getting covered up so you dont kill the engine.

 

all the info i can find about the killer dowel pin update says it's for 94-98, i'm assuming it's also for the 1st gen cummins? sure would imagine, didnt know of much differences in the 12valves.

 

it's pretty much a 12 valve problem from what I've seen. however, just like the LP's they can last for 300,000 miles, or die on the dealership lot.

 

no communication with the computer from the scanner. Got to lookin around under the hood and noticed a couple wires goin to the EMS were clipped and of course after i soldered them back up the speedo quit working. the harness has been broken into before, i have NO idea what for. I suppose for $4200 I cant complain too much. Friday I'll take it into a electrical specialty shop and let them track the rats nest. the KDP seems easy enough to do on my own, and after shoppin around a bit, a k&n would be relatively the same price as one of the big paper filters. No carquests around here! i appreciate your help! ill keep ya informed.