I’m going to replace my factory cooler, it’s actually been a really good unit with no issues, but a lot of the fins are smashed in and I’d rather just replace it sooner than later. Does Mopar even offer the original unit anymore? I can’t find a PN for it. I’ve considered doing the Mishimoto as it claims to be a direct fit, but noticed @Dynamic offers the 3rd gen version on his website, but not the 2nd gen version. I assume he excluded the 2nd gen version for a reason.

Here's one for $464 

 

https://store.mopar.com/oem-parts/mopar-transmission-oil-cooler-52028574ah?c=Zz1jb29saW5nJnM9bGluZXMtdHJhbnNtaXNzaW9uLW9pbC1jb29sZXImbD00MyZuPUFzc2VtYmxpZXMgUGFnZSZhPWRvZGdlJm89cmFtLTI1MDAmeT0yMDAxJnQ9YmFzZSZlPTUtOWwtbDYtZGllc2Vs

Look in the part number book.

https://mopar1973man.com/cummins/articles.html/24-valve-2nd-generation_50/part-number-lookup-tool-2nd-gen-24v/

I got a oil cooler with twin 12v fans brand new, it is for the hydraulic system on a  mobile Terex Pegson screen, it's maybe 14" to 16" long,  10" ish tall and 3" wide, sat on the shelf and as usual not got around to fitting it.

It's got fair size inlet/outlet but I have a good working relationship with a couple of hydraulic shops so fittings and adaptors aren't a problem, my plan is/was to pipe it in alongside the original.

Another trick idea. Add a ISSPro EV2 trans temp gauge, also order the optional relay for the gauge. Now program you fan on temp and the trans temp gauge will automatically control the fans for you. 

If I were to get the Mishimoto stock replacement cooler, is there any reason I couldn’t use my oem cooler as a remote cooler under the bed with a couple of 5” Spal paddle fans? My other option is to install the Mishimoto and add 1 Spal fan on the bottom to move some air in stop and go traffic. I’d probably just let the fan run constantly in the summer, and unplug it during the winter.  Again, I’m having no cooling issues right now, this is just me using an abundance of caution to protect a brand new transmission I just spent a small fortune on. 

I wouldn't have thought stop and go traffic would be a problem heat wise, my truck trans temp cools down when in stop/go, towing heavy is where the heat comes from especially when on the convertor.

When you fitted the new trans did you flush the stock cooler ?  if in any doubt about it then a new stock replacement ( Mishimoto or whatever) stock location benefits from the fan when in traffic. 

Then if you really want to add another stick a aux cooler under the bed somewhere and as @Mopar1973Man says it can be wired for fans to come on either at a set temp or on a switch

 

I've never had a trans heat problem with my truck, although I did check the level on friday and it looked a bit too dark for my liking so once I get back from Denmark  1st to 15th of June I'll be changing the fluid, that being said I've never really looked at the cooler so I just took a look on rockauto at a stock trans cooler, It does look a little big, narrow and flimsy to mount under the bed especially on a short bed but I could be wrong

As for your question, you stock cooler is just a cooler and if it's an aux under the bed it won't care assuming you can find somewhere to mount it that is

The ISSPro EV2 gauges can be programmed to control the fans. Basically have the Trans Temp gauge set for tripping the aux relay that plugs into the gauge and it can control the fan. Then you can also program the warning light for a higher temp. Being I've got manual trans I really don't need this function but... I might be designing a trans cooler set up. 

Didn’t @Dynamic have a auxiliary cooler setup he recommended?

Just now, Royal Squire said:

Didn’t @Dynamic have a auxiliary cooler setup he recommended?

Yea, he likes the Derale 15870, which is probably the smart thing to do. The Mishimoto would be the easier/cheaper thing to do I think, and then if that wasn’t cooling enough I would add a remote unit with a fan. 

Biggest thing is getting the torque converter locked up as soon as possible. Proper final ratio of 3.55 to 3.73 is going to keep trans temp down more so. Trans temp is a sign of power loss by too much supplied power and/or working load.

Agree, but most seem to have bigger heat issues in stop/go traffic than they do during towing. That’s just an airflow issue. 

If you're working the converter, you're going to make heat, but you're also multiplying torque. It's science... If you're making more heat than the factory setup will keep cool, it's time to take a look at your setup. Is there a problem? Are you using it in a unique way that requires a unique solution? Some do, most don't.

 

As far as a replacement for the OE unit, the Mishimoto would probably be my choice. I do very little with the 2nd Gen trucks themselves anymore (I only bench build the transmissions these days), so I didn't even know that Mishimoto made a drop-in for them.

4 minutes ago, Dynamic said:

Are you using it in a unique way that requires a unique solution?

I don’t think I am, and I’m not having any issues with excessive temps (couldn’t get it over 175 towing my horse trailer last week). But, the only time I’ve ever had my trans temp light come on was when I was creeping through a field towing a gooseneck trailer loaded with hay  in the summer. I remedied this by getting into 4wd lo. So what I’m going for here is peace of mind I suppose.