I had read on an RV forum that the 4R100 trans isnt very good for towing. Is there any truth to this?

I always thought the 4R100 was a tough trans and WAS good for towing.

Thanks
Brian

 

IIRC this is the same trans that was behind the early 2000s Super Dutys so yes common saying here on FTE is that it is the "beefier" or "stronger" transmission.

Don't forget that excessive heat will kill any automatic transmission so I recommend a transmission cooler if you are going to be pulling frequently.

 

What is IIRC?

 

"If I recall correctly"

 

Thanks 97 I couldnt figure that one out to save my life! LOL

 

I will be pulling the trailer around a bit so I added a trans temp gauge. My first longer trip with it is coming up in a few weeks so I will keep and eye on the temps. I have the trailer package so it has a small cooler on it now. It seems to stay around 160 driving in 85 degrees outside temps around the city.

Any idea what my normal temps should be?

 

I had a 4r100 behind a 7.3 TD in an F350. I had to put a torque convertor in at around 100k, and rebuilt it at 200k though it never failed, just preventative maint. on a heavily used work truck. That truck was either towing a 8000lb empty trailer, 15,000lb loaded trailer, or plowing snow on a 10 acre lot in the winter for its whole life. That 4r100 was tough, tougher than the worthless Allison I tried in an '01 Chevy.

So...It will be fine towing anything the Expy can handle. You have made a major step by deciding to monitor the temp, just keep it under 250 degrees, 160 is fine around town. You will se it jump with a load on and the torque convertor unlocked, otherwise the temp should stay low like that. Keeping fresh fluid and filter in it will help too, 30k mile intervals are a good idea.

 

Hi BG,

Thanks for all the info. I do change the fluid regularly and always use synthetic in it ( it was just changed about 2000 miles ago). So I should be ok with it. I added the temp as I do plan to tow alot with it and the trailer is about 7500# loaded and my Navigators towing capacity is 8900# (thats on the hitch) so I thought I better keep an eye on the temp in the trans.

Thanks again
Brian

 

Sounds like you are ready to roll. Just kep in mind that when you hit a hill, and the convertor unlocks, that is the time to keep one eyeball on the gauge. The temp will come up quickly.

Just let it drop a gear and turn some rpms. I really liked the fact that my Expy, like your Nav, has the 4r100 and the 9.75 axle, essentially 3/4 ton parts. You should be able to run a well maintained set up pretty hard, without problems, for a long time.

 

Hi BG,

I took the truck Nav for a ride with the trailer hooked up. The trailer is about 7500#. Took it for about an hour on the freeway and the trans temp ran right at 210 degrees, and it is 85 outside temp. I confirmed that half way I stopped and checked it with my handheld infrared thermometer by scanning the pan at it read from 200-210 on both sides of the pan.

In the city it never got too much hotter maybe 5 degrees hotter in town for about 15-20 minutes.

I have the stock tranny cooler. It is a cooler that has the inlet and outlet on the bottom of the cooler itself so I dont think it is plugged.

Any idea why it is running so hot? Or is this normal?

Also is it ok to run it this hot for a 3 hr trip? (we are going to Cedar point next week)

I dont have time before the trip to order a new trans cooler and install it on the Navigator.

What ya think?

 

Synthetic oil should be able to take 300 degrees. You still have a cushion there, though not as large as I would like.

If it doesn't go much beyond the 210 mark, I would make the trip. I would still use 250-260 as a pull over and cool down point. I would also increase the size of the cooler asap. Then keep an eye on the trans fluid. Higher heat will break it down more quickly.

Did the coolant temp seem to come up at all during the test? I think you are putting a little more heat into the system than the tranny cooler can handle and are now shedding some of that heat in the engine radiator. That should stabilize it though it is not ideal.

 

The coolant temp never came up at all. I have the Taurus electric fan and it does a pretty good job of keeping the engine right at 200-205 degrees when at idle. (I have a 190 thermostat in the truck it is stock) When on the highway the fan doesnt normally come on unless Im towing the trailer then it pretty much stays on all the time. I might put the stock clutch fan back onto it and see how it performs too.

It doesnt go beyond the 210 mark and I have to work it to get it to go above that in the city but then in the city it goes up 5 degrees in about 20 minutes, and then stays there.

I checked the tranny fluid and it smells fine, no burnt smell at all.

I will look into getting a tranny cooler locally, I dont think they have any here it seems that this town is not the best to get parts in.

 

Normal.

210*-220* is not out of the ordinary under the conditions that you describe.

 

[QUOTE=Big Greenie;9071860]If it doesn't go much beyond the 210 mark, I would make the trip. I would still use 250-260 as a pull over and cool down point.[QUOTE]

Agreed.

Sorry, disagree.

If normal operating range is 180*-220*, and he is running 210*-215* max, what is the purpose of trying to get it any lower? Why will 195*-205* do him any good?

He is operating in the normal temperature range for that transmission, albeit at the higher end of the range. Getting into the lower end of the range serves no purpose.

If lower tranny temps are always better, ALWAYS, then the logical progression is to hook a refrigeration system onto the tranny and cool the tranny down to 0*, or even lower. Lower temps are better, right?

 

His normal operating temp is 160 degrees. At 210, you are at the top end of the safe operating range. At 180-190, I would agree with you but at 210, you have left very little room for error. I never recall my F350s 4r100 running that hot even with twice the load he is pulling, hence the reccomendation to buy some additional cooling capacity. I also do not recall the E4OD in my motorhome running that hot at 30k gross.

210 is warmer than I would run it if it were mine. If you think that is normal, go ahead run like that. My suggestion remains unchanged, I would run it for now, and buy some additional cooling to try and bring the temp down some. I never suggested he was in the danger zone, I wouldn't have said I would "make the trip" if I was at all concerned. I also, personally, wouldn't run it that hot on a regualr basis. The larger cooler will extend the life of the fluid and the trans, would you dispute that?