Fan Roar and Tranny slip

[Matt1984]

New Member, 1st question.
The title sums it up. Start the vehicle, let it warm up (Wisconsin winter). The in-dash temperature reads right where it should, no fan noise, blowing cold air through vents. Put in gear to and the fan roars while city driving, temperature holds still get cold air. I Get up to highway speed the roaming is gone or muted from road noise and engine noise and the hot air returns to normal.
Any ideas? I am thinking from what I have read, thermostat or fan clutch?...will need to check coolant level, this just happened last night

Now the slipping tranny comes into play, trying to get it up to highway speed was tricky as it didn't want to find the gear and kept revving and slipping like it was kicked into neutral. This is a new problem.

Now cruising at highway speed is fine until slowly want to accelerate and gently push gas then the tranny stutters and clunks and engine revs, but is fine when the O/D is off....its happening more and more frequently.
Any ideas on this? I am lost

The reason I posted the two together is because the new tranny problem and read a post somewhere about the Thermo Bypass being faulty and was misinforming the PCM that the trans was overheating and the PCM was locking up the fan clutch to pull more air to compensate.

Thanks in advance.

 

[Flag Gibby]

Since you have the V8, check the temperature sending unit to make sure there are no issues with it since that controls the fan clutch speed at low vehicle speeds (and other things like you said). As far as the tranny issues, that to me sounds like a combination of cold fluid and a low tranny fluid level.

 

[jakesc7]

Have you tried the PCM update? Any dealer can do it and it helped my Explorer w/ loud fan noise. Something about the computer reading the transmission temp. incorrectly... Eventually found out that the OEM radiators are pieces of crap too...

 

[Matt1984]

Thanks for the reply.

I have not had the PCM flashed, maybe afraid they will tell me I need all this other crap done...but as stated might just plug a new temp sending unit in and then go from there. Does any one have a location of this?

I am scheduled for a tranny flush this week which should take care of any low fluid levels and/or dirty fluid

I am wondering why neither of you suggested a bad fan clutch??
If it is a fan clutch is it possible to replace just the clutch or is the electric motor (viscous?) and clutch all one unit...meaning I can not re-use old electrics?

 

[Matt1984]

Update to this fiasco..started leaking coolant pretty bad. Took the exp to the local guy this morning where traced the leak to water pump. He said the fan roaring along was trying to compensate for lack of coolant that pump wasn't getting from the leak... With that the tranny flush, oil change and oil temp light the total came to 400...Most of it labor.

Any comments?

 

[boominXplorer]

With an electronic fan clutch low coolant can cause it to lock because it will be getting a false signal. If you never checked your coolant when you had the issue it was obvious it was low and leaking after the fact.

I would also make sure your coolant wasn't contaminated with transmission fluid which would point to a internal radiator leak. That would cause trans troubles pretty quickly.