99 Expy 4x4 Transmission Service Question

[Coey326]

I have a 99 Expy XLT 4x4. It has 125,000 on the transmission and and 1000 on the new engine. I am driving this on a cross country trip with the wife and I am currently changes all fluids and making sure the maintenance is spot on.

Question 1. Is it a good idea to replace the trans fluid and filter? Seems like people are afraid it will mess up the transmission.

Question 2. Does the transmission have a hidden cooler? Most coolers are located on the outside of the radiator but I don't have one located there. If not I will install one.

Thanks in advance for your help and advice.

 

[Bedrck47]

Welcome to the Forum

For your second question There should be a trans cooler inside of the radiator Also if you have the heavy duty towing package there would be an external trans cooler located in front of the radiator. If that isn't there then you don't have the towing package

If you want you can install the external cooler

 

[Coey326]

By looking at the Radiator, how can I tell if I have one inside? It has a trailer hitch and wiring in the rear so Im guessing it came with the towing package.

 

[Bedrck47]

You would see two small diameter metal lines going into either the bottom or on the side of the Radiator

Also do you have a 4 pin or 7 pin connector located at the trailer hitch

4 pin would be the light duty trailer package
7 pin would be the heavy duty package

You can also go onto ford etis and enter your vin number and get a readout of all that was on the expy when built

 

[Sir William]

If you don't have an external cooler in addition to the one in the radiator, add one. The number one enemy for a transmission is heat. The rule of thumb is that every 10 degrees average you can drop the fluid temp doubles the life of the transmission....and that's from one of the designers of the 4R70/100.

If you're adding a cooler, go for plate style rather than a tube and fin type. The plate style is more efficient at heat transfer. Look for the biggest unit you can make physically fit generally -- a 30k to 40k lb cooler should be a good option. Your transmission will thank you.

 

[Coey326]

Thank you for the advice. I will look into that and have it done.