2000 4R100 Lines

Sterling B. · Feb 23, 2016

Ok, I need some help figuring out the way things are supposed to be vs. the way things are. I'm hoping Mark Kovalsky will see this and maybe shed some light on the issue.

So, the truck is my 2000 F250 with late '99 build date. Currently, lines go directly from the trans to the tiny factory auxillary cooler and then straight back to the trans. This might explain why my trans temps get crazy high really fast when I'm towing. I'm really needing to get a larger trailer, so I need to take care of this before I tear up the trans.

Next step, I go to fordparts.com so I can view the diagrams and part numbers... only to NOT see any lines for a truck prior to 2/6/00 that go into the radiator.:cursing: Am I just that blind or did it never go into the radiator from the get-go? If that's true, how can I bring my temps down? Can I use the other lines for a post 2/6/00 to route the fluid from trans to radiator to aux. cooler? (I believe that to be the proper routing...) Any help is appreciated, thanks in advance!

JD3020 · Feb 23, 2016

Might not just ditch the factory coolers and get a large Tru-Cool? $120 and they do a great job, kept my trans under 150* when grossing 20-23k on the highway in my OBS.

Vader's Fury · Feb 23, 2016

I used pushloc hose and built my own lines. Was easy and not that expensive.

Also will not rust. If you have the cooler in your radiator, I would look into going that route.

And it goes trans to rad to cooler to trans.

Sterling B. · Feb 23, 2016

Vader's Fury said:
I used pushloc hose and built my own lines. Was easy and not that expensive.

Also will not rust. If you have the cooler in your radiator, I would look into going that route.

And it goes trans to rad to cooler to trans.

Perfect! This definitely sounds like the easiest, most affordable option! Do you recall off-hand what thread size the fittings are on the radiator? After a little google-fu, 3/8" NPT maybe? 3/8" line adequate as well?

Vader's Fury · Feb 24, 2016

I do not remember.

I believe that Marty's Diesel sells a kit to do this. You might want to contact him. His prices might surprise you.

3/8' should be adequate.

Sterling B. · Feb 24, 2016

Thanks! I'll send them a message and see what they might have to offer.

I was also thinking it might be a good idea to add an external filter while I'm at it such as this one from dieselsite for a little added protection...
http://www.dieselsite.com/dieselsitetransmissionfiltersystemtfik.aspx

Mark Kovalsky · Feb 24, 2016

From the start of the '99s until mid year 2000 there was no cooler in the radiator. The radiator cooler was added as a running change during the 2000 model year.

The BEST trans cooling is to replace the radiator with one that has a cooler, then replace the current cooler with one from a 6.0L truck.

Sterling B. · Feb 24, 2016

Mark Kovalsky said:
From the start of the '99s until mid year 2000 there was no cooler in the radiator. The radiator cooler was added as a running change during the 2000 model year.

The BEST trans cooling is to replace the radiator with one that has a cooler, then replace the current cooler with one from a 6.0L truck.

This makes me feel a LOT better... I was a bit worried the PO or someone even before him had eliminated the radiator lines. I replaced the radiator a couple years ago when the top tank started to leak and it has the fittings for the transmission lines with caps still in place. I'll definitely be making new lines and likely put in an external filter as well in an attempt to keep the trans a little healthier. For the time being, I'll keep the small cooler and see where I'm at as far as temps are concerned and upgrade as necessary. I appreciate your reply!

NC714 · Feb 24, 2016

Mark Kovalsky said:
From the start of the '99s until mid year 2000 there was no cooler in the radiator. The radiator cooler was added as a running change during the 2000 model year.

The BEST trans cooling is to replace the radiator with one that has a cooler, then replace the current cooler with one from a 6.0L truck.

I did exactly this on my late 99. It dropped my transmission temps dramatically. I highly recommend this route.

NC714 · Feb 24, 2016

I forgot to add...

I purchased new lines for a 2002 model truck, one from the trans to radiator cooler, and the other from the "aux cooler" back to trans. The one from the trans to radiator cooler was a direct fit. I had to make a new line to go from the radiator cooler to the 6.0 cooler, which required going up from a 3/8" line to 1/2" line. Then same from the 6.0 cooler back to the trans hard line, 1/2" hose at the 6.0 cooler to 3/8" hose at the transmission return line. This information can be readily found by searching for 6.0 trans cooler installs. Hope this helps!

Sterling B. · Feb 25, 2016

It looks like I can get the lines I need from rockauto (DORMAN) for around $70 spec'd for an '01. I'd kind of like to make my own with push-lock hose simply so I can route it how I want to, but I'm having a hard time finding out for sure what fittings are needed. :fustrate:

psduser1 · Feb 25, 2016

The stock location is actually pretty decent, from the trans to the front of the engine. Well protected, and out of the way.
I'd say just modify the hard lines as needed between the engine and frame (core support) as needed. There are already rubber pieces there to allow for body/engine flex. Not 100% sure, but I believe they are a metric hose. I used 3/8" hose with pushrod barbs to the transition at the 6.0 cooler. I made the size change, 1/2" (cooler) to 3/8" (truck) quite close to the cooler.
At the stock line connection, I did have to use a worm clamp, as the pushrod style connector kept dripping. Course, my truck was modded at 300k, lol. Might have been ok on new rubber.