Transmission ID

[KMahnke]

Hello all. Posted in the cummins conversion section about a 1990 D350 6BT Ram I just picked up for salvage. (Is it worth it) I tried this search engine and google and the rest of the web and can not find any specific information on what automatic transmission is in this truck. Three speed via the selector on the column--PRND2l but I'm not sure if it is lock up capable or not. Closest guess is the venerable 727 or possibly the A518. The unit seem to function well but I need to know what the transmission really is to select the proper mods available --tighter converters, shift upgrade kits etc before I shoehorn this combo into the 1/2 ton GMC. Any tips,help would be greatly appreciated.



Thanks

Kirk

 

[dan brooks]

The trans should be a 727. The A518 (a 727 with an overdrive bolted to the back) was used from 1991. 5 to 1993. The 727 and A518 trannys used in the 1st Gen trucks were not lockup capable.



There are several good aftermarket converters available: Hughes, TCI, DTT, Suncoast, etc. I have the Hughes and I'm happy with it. I also had a Trans-Go TFOD-Diesel shift kit installed when mine was apart - I like it because it gives a firm shift, but its not harsh like the street/strip kits I've used in the past.

 

[KMahnke]

Thanks. I have to get off my arse and crawl under the truck and take a looksee. Good tip about the shift improver kit as I dont really want a "knock the mud out of the wheelwhells" type dragster shifts common with most kits. I'm doing this swap on a budget and I want to make the existing drivetrain IE 1965 12 bolt rear--last as long as possible. I am not trying to build a hot rod. Just a strong reliable truck that gets reasonable fuel milage.



Thanks again

Kirk

 

[cerberusiam]

Should be a 727. If you have no OD button on the dash below and left of the radio it is a 727. Adequate in their stock form but suffered from lack of hard parts and OD. That trans is also rather rare so you maybe better off selling it and rounding up a better trans for your application.



If you try to use a trans without OD and don't modify the engine you have a top speed around 80 mph with a 3. 5 rear end and that is winding pretty hard. Makes plenty of noise also. The early trucks used a 3. 07 to get some more speed but that wasn't as effective as an OD. If you have one of those that could be worth some $$$ for conversion also.



I am in the process of doing about the same thing only using a late 80's suburban for the project. Still compiling a list of the best pieces but here is what I have found so far. Forget the 12 bolt and get a GM Corp 14 bolt. The TQ from just a stock motor will kill the 12 bolt faster than you can rebuild them. Given the availability and cost of GM pieces IMO its probably easier and cheaper to build around a GM drivetrain. The best combo I have found would be a 4L80 and an NP205. If you are 2x4 delete the t-case. Cummins uses an adapter plate to bolt the trans to and I am told they can look up the correct part # for a match to most transmissions. That hasn't been verified yet but it sounds promising. The biggest question revolves around the converter and the differences between lockup and non-lockup but custom stuff is available. Good luck on the project.

 

[1stgen4evr]

You have a PM

KMahnke, I want to know about the rear axle. I am looking for a 3. 07 dually setup. Even with some damage.



1stgen4evr

James

 

[1stgen4evr]

transmission for cummins

Allmost forgot. I have the parts to connect the cummins to a chevy transmission should you want to go that way.



CRivero in Miami was doing the same conversion. He might have some tips.



1stgen4evr

James

 

[dpuckett]

DONT forget to beef that 1/2T suspension. The Cummins Super B weighs in around 1000# fully dressed with flywheel. A big block V8 is around 750#. Cant hlep you with the transmission, except to say that in 55mph territory, you can go in 3rd with the 727 and be just fine. I dont go into 5th with my 4. 10s until about 50.



Daniel

 

[KMahnke]

You know the more I look at this old truck the more I'd like to keep it intact. It's kind of grown on me. The only serious rust on the thing is the rocker panels. The cab roof is starting to show some blisters below the clearance lights but a fiberglass "vinyl" top would take care of that. It looks like this thing was top of the line when it was new. All power options including windows, mirrors and door locks. A/C, sliding rear window and of course the venerable 6BT and 727 with the much sought after 3:07 Dana 70. Someone told me that if I can have the truck certified as roadworthy and can provide proof to the state that a clear title may be possible to obtain. It's an option I'm seriously considering.



As far as the 1/2 ton goes I've already got some TRW variable rate springs picked out for the 6. 5 diesel option with air for that model truck. The frames are the same on the 1500 & 2500 It's just the A arms and spindles are beefier along with the brakes and six or eight lug hubs. I'm not going to pull anything with it so stopping 10K lbs isn't an issue. Its more of a for the love of it project.



I have a healthy respect for these diesels and this particular one has struck a chord with me. I cant believe I stumbled across this thing and it runs so sweet--- :{ I havn't told the previous owner I got it running yet as I'm afraid it would break his heart. He asked me to tow it out of his yard and not start it and drive it away. I had it running a couple of hours after I dragged it home . Now I'm starting to get attached to it--I think I'm gonna call it "Christine" :-laf I really dont want to see it go the crusher.



Oh well. We have a Hurricane headed our way and that will take my mind off of it for a few days anyway. Lots to do for now.