1990 Cummins Build,, yep finally moving up!!

[redthies]

Andrew... You may have to give Rik back his brush guard! I think you guys will figure that you are 100% right on the cab switcheroo. Not only have I never seen or heard of a club cab on anything diesel pre 91, I know they didn't do a club cab short box until the mid 90s.

 

[Wyo-M880]

I was the owner of that not the builder of it, they told me it was t-boned regular cab, frame bares a dent where the cab mount was originally, they had said they found another cab a 79 off another wrecked truck ((the 79 dodge which bears an etched murial of a western seen on the drivers club cab window on was that me and my dad bought at an auction in riverton 12 years ago, was a 79 club cab with a 360 auto short bed, the guy we sold it to was *** ended and the box and rear frame was total loss, i guess some one picked it up for the sweet front clip or something and shelled the rest, then the owners of the yard built this creation)) was a great runner, just misses wanted a 94-99 ext cab dodge, she hated the 90, i loved it but i already had too may projects, 1973 Dodge w100 Short bed w/ 383 built for sled pulling, 1986 suzuki samurai, Ricks old 96 1500 and a 86 chevy k20 pickup that i just recently traded for a 97 2wd ram 3500 Cummins, so i know rick was looking for a cummins and i had one so i think it was good all around*here is a pic of what it was when i got it

 

[Rot Box]

Welcome to the forum Wyo-M880 :bike_rider: Thats good to hear it sounds like everyone won in that deal

I was going to say to my knowledge the short bed/extended cab option wasn't available either--I figured someone put that cab on a long bed/reg cab frame at some point. If you don't 'need' the long bed the wheelbase you have now would be great for off roading.

 

[pulltilbroke]

Negatory on the Grille guard, that thing save the front of my 90 this weekend after a deer strike.

When the cab was installed did they use the 81-3 dash or did they just leave the old 79 dash in?

FWIW the ecsb was available on 1/2 tons from the introduction of the ex cab in 76 but why they didn't offer an ex cab on a Diesel til 92 is anyones guess.

When I say pieced together i don't mean it in a bad way at all. I think a good amount of the older rigs on this forum have been put together, both of mine included. Shoot my 90 sports parts from the early 80s all the way up till about 05.

 

[Wyo-M880]

they used the 90 cab interior, iirc, they change the steering column in 91.5 to the wider which made new changes to the fire wall and inter cab dash parts, so it looks like complete bolt in except for seat, it was a 79 spilt like the ramcharger (not console) and it was ratty, i found a 93 seat for 20 bucks out of a scrap yard and worked for it

 

[rikinwyoming]

We are both happy with the trade which is all that matters... I have been around offroading and rockcrawling all my life so I believe that things are meant to be changed and customized to the usage intended. I am looking at cutting off the flatbed at the rear leafs and putting 45 degree cuts as well to make it more offroad friendly, just haven't finalized the design as of yet. Also have to find a good source to change the ring and pinions (want something more efficient for the 35-37 inch tires I will run, and to add front/rear selectable lockers as well). The large front bumper is on and I intend to keep it there. Paint is coming, I am leaning toward to making it red again.... red and black is always a good combo...

 

[Wyo-M880]

Dana 61 regear techhttp://ramchargercentral.com/technical-discussion/dana-61-re-gearing-info/

 

[rikinwyoming]

Pic of the bumper in question which I re installed,,, yep it's staying ...

 

[rikinwyoming]

Ok, now a few questions for the people in the know...

The cummins seems healthy albeit I need to do an oil change this coming weekend... other then that healthy! The A727 tranny seems to shift pretty fast, as it is in 3rd gear at 40 mph even though the axles are geared at 3.07's in the pumpkins and the 35 inch bfg's....

What I would like to know, isn't a gear ratio closer to 4.10 more appropriate for the large tires I am running? The diesel seems to be getting around 14 mpg currently. Also, should the A727 be shifting that fast, or is this indicative of a problem I am not aware of. Yes I would love to have a 4 spd auto that will hold up to the cummins , but I am not aware of a direct bolt on option. Lastly, I was going to put amsoil in this beast, but it is very pricey... is Rotella 15w40 good enough with frequent oil changes? Thanks in advance, I want to do this right the first time!

 

[redthies]

I don't think 3rd at 40 is totally out of line, unless you have it to the floor. For oil, Rotella is a great oil and if you keep on a 3000 mile schedule your engine should be very happy.

 

[bftank]

start researching the 47rh,

its a 4speed auto came in 94-5 dodges with cummins, minimal electical control, can be built very beefy. has a lockup convertor i believe.

there is also the a518 that came in 91-93 i believe, non lockup convertor has overdrive.

i am a little rusty but i believe the a518 was based on the 727.

redthies-
i think you are think of the later versions of the 47rh, the 47re and the 48re. these are computer controlled transmissions built after 1996 for the 47re and 1999(?) for the 48re. doable but more complicated from what i understand.

cummins forum, 1st gen.org, and compd are great resources for the cummins.

 

[Spencinator]

My 47re will shift into OD at 45 mph. I have 3.55 gears and 35in tires. Driveablility is fine but I will be swapping in a 5 speed when the truck is paid off. If you add any power and tow you really need to put $3k atleast into your trans to have a reliable auto. The thing that I hate most is how much power I can feel is lost through my 47re. Also not being able to select a gear on hill climbs.

I noticed you said you want to cut the bed shorter. If you keep the bumper on the front its not really worth cutting down the back in my opinion.. You lose your approach angle which wont help your descent angle. Something I would consider doing if I had that bumper is cutting everything off except the main part of the bumper. I would also be a little nervous on cutting the frame of a 3/4ton truck unless you never plan on using it for that rating again. I love the first gen trucks and good luck on your build!

 

[Saiyan66]

Sounds like you are off to a good start, and looks like a good trade to me. Since you are planning for bigger tires and lockers, I would start by swapping out those Selecto hubs. That is the one part of our old 90 that constantly gave us problems. Everything else was bombproof.

P.S. The A518 transmission is indeed based on the 727, but is an overdrive trans. The 92-93 did have a lockup torque converter to my knowledge. Prior to that did not as I have a 91 and there is no lockup. Still if you are considering transmission swaps at all there is really only one affordable durable option: NV4500. Trust me there is NOTHING like a Cummins with a manual trans behind it.

 

[pulltilbroke]

the A518 never had a lock up coverter in the diesels, thats whythe 1stgen auto trucks are so slow. i would toss the auto in the junk and do a 5spd swap.

As far as oil I always run a CI rated oil i my trucks. All this new CJ rated oil has had all the god stuff taken out.

 

[SChandler]

On the oil front, you don't need to change it every 3000 miles. If you use a non-synthetic oil, then 6000 miles is the recommended service interval for oil and filter per the factory service manual.

The reason the Amsoil is so expensive is because you can go to an extended change interval. If you use their filter, they suggest a 25,000 mile change interval. I have been doing that in both trucks I've owned (a 90 Dodge Cummins 2wd and my current 92 Dodge Cummins 4wd) and not had an issue with it over a combined 200,000 miles. With as much oil as these trucks use, tracking the oil condition via oil analysis is probably the smartest thing to do.