98 E-350 trans temp, cooler issues?
Just starting to get my van back in shape now that I'm getting ready to be towing my cars around quite a bit. I bought this van back in 2005/6 or so from a guy who used to tow a camper with it. It's a 1998 E-350 with the 7.3, and the previous owner had done some mods to "support" his towing:
Two trans coolers
Well, when you are in the middle-of-nowhere in Indiana and you get your mods done at Walmart, the wiring is not exactly the best. Needless to say, the trans gauge eventually went out and I just finally got around to repairing it. The shop put a 120-250 degree Autometer in there, and on the way home today (simple highway cruising @60mph) the trans temp crept all the way up to 250-ish indicated.
I just had a complete fluid service done (coolant, transmission, differential, oil) and I am wondering if the trans cooler(s) haven't been clogged for some time. It looks like there are two additional coolers plumbed after the in-radiator cooler.
So, here are the questions:
1) On normal highway cruising with this type of vehicle (is this an E40 trans?), what should expected temps be on the trans? I've seen anything in the 130-180 range as being "normal", but anything over 200 seems "dangerous" or wrong/off.
2) Does it seem like this is likely a clogged cooler issue? I saw some other posts discussing valvebody or torque converter issues, but the transmission shifting seems to be just fine. Doesn't seem hard or slipp-y. Since the fluid was just changed, but I did not have a complete flush done, was this a mistake? We did change the pan filter. The shop did not feel that the fluid that came out was burnt.
3) Are the two coolers a waste/excessive? Pretty much my only use for this vehicle is either hauling friends around or towing ~6000+lb worth of car and trailer. So it's either just a highway car, or it's pretty much loaded down. Seems like one additional cooler over the factory in-radiator cooler should be plenty, but I'm open to opinions.
Thanks in advance, and looking forward to your input!