MoparTyson

I'm planing to swap a cummins into my 85 W350 crew. The donor truck a 92 has a 5 speed but I want a automatic. This is my first diesel project. Can I use the auto in my truck???
Any suggestions greatly appriciated!

ofcmarc

The Diesel trannys have a different bell housing. You'll need a donor from a diesel rig. If the 5-speed is good though you might have luck swaping an auto from someone who wants a Manual.

MoparTyson

Thanks for the info. How does the 518 hold up to the cummins? Went threw several of them in my dakota!

ofcmarc

Fairly well when built right......

https://www.dieseltruckresource.com/...s-t160276.html

loch

If the 518 your going to use is from a gasser it might have limited life behind the diesel. They were good transmission but tq of diesel isn't friendly. What gear ratio is in the truck now? Reason I ask is the non O/D trucks had 3.07 ratio, if your gasser is lower and I expect 4.11 , its going to be slow.

MoparTyson

My truck has 4.10 gears but I'm runnin 37 inch tires. Dp you think I'll be ok with a 3 speed or should I get a OD?

Subliminal

I'd go 5 speed...they're way more fun, put way more of the power to the ground and seem way more reliable to me...but i've heard that initially they had a lot of issues.

loch

imo if you run the 4.10 get OD , fuel mileage will suck if you dont.

MoparTyson

Mileage couldn't get worse. I'm gettin about 10 mpg!!!!!!!!!!!
What's a good RPM range for a cummins at 70mph???

loch

At 70 with 4.10 gears, without O/D. uhm all it has. With O/D your mileage be way on up there, I get 22 on highway if I keep my foot out of it.

Onemoparnut

Yea 4.10 is alot with a 3 speed but wouldn't the 37in tires help it alot?

MoparTyson

I hoping the 37s will help. I'd rather run a 727 I've had better luck with them in the past.
What rpm are yall runnin at 70-75 mph???

dzl_damon

2000 rpm at 70 would be nice if you are setting a truck up. I get a little more rpm's with my 3.07 / 3spd set up. I would highly suggest an od definitely!

Where do you live? I have a 518 with OD/ Transfercase set up to trade for your 5speed/ transfercase set up

dieselJon

MoparTyson, the A518 that's in the diesels (actually, all of them) is a 727 with a OD housing bolted up. To get a A518 to run good, get a shift kit, adjust the bands (there is a link here to do it), and put in a good torque converter. That is all that's needed to make a good A518.

Maybe your Dakota had a A999? Did the Dakota have a lock-up converter?

MoparTyson

I'm in arkansas. Sorry the 5speed is a 2 wheel. I was gonna use a divorced transfer out of a 72-74 truck.