Overheating issue ??

[DaveHess]

I was waiting for you Cerberusiam. My gut told me the same thing but I wanted some validation that I wasn't just grabbing at straws. I see you have Transgo listed in your signature. Was that the VB kit? I need to replace my governor and solenoid and I was thinking of doing the Transgo kit for the VB. I have some issues with RPM "flaring" as the 48RE goes into OD. Would the Transgo kit "tighten" or firm up the shifts into all gears? Thanks for your time.

 

[cerberusiam]

A friend called form the road delivering trailers. Truck was heating on hills. No codes and it would engage and he could hear it. Got a Doorman replacement clutch from one of the generic parts stores. It helped but still running hotter than normal. Told him to get a dealer part as I suspected from other experiences the Doorman was not quite the same. Swapped in the factory replacement and problem solved. The fan noise was much more pronounced under load also. Even though it will enage and there are no codes the fan never locks solid and the fluid coupling will deteriorate until it doesn't pull enough air. Its like a TC, not all fluid couplings are created equal. Thats been my experience when thermostat is good, rad is good and clean. The one caveat I have seen is a cracked head will drive the temp up and it is hard to determine of the excess heat is causing fluid loss or the pressure.

A shift kit may clean up the shifts if it is the apply pressure causing the lag and a flare. You say it is flaring into OD, is that before or after the TC locks, and does your TC lock almost immediately after the OD shift or wait a bit? Under a heay load and throttle with extra power the stock TC will flare pretty badly when you hit OD. Under normal driving it should not. The big question will be is the flare related to the TC or the OD clutches. A shift kit will not compensate for wear but it may cover it up with higher pressures. A flare into OD can be clutches, pressures, or just the TC. Really tough at times to tell.

I would do a shift kit, gov solenoid (the GM stle conversion), new transdcuer, billet accumulator, billet front servo, billet band strut and anchor. Then test the charactersitics afterward.

I would not do a TransGo kit if you are not intimately familiar with the install. They are quite involved with a lot of drilling and passge plugging, it has to be done a certain way, and the instructions frankly suck at being intuitive and neatly layed out. Superior makes a shift kit that is a lot easier to do, much less intrusive, and can be reversed. A TransGo cannot be reversed after install because of its complexity. Works really good but it is a 1 shot deal with no return flight.

 

[DaveHess]

You ask some interesting questions. I thought I had played this out in my head to the end but apparently not. The flare is only noticeable under throttle or while towing. Normal day to day stuff I don't notice any flare. The normal day to day driving gives me an indecisive 2-3 shift that my local dealer blamed on my driving style. I don't hammer on this pickup. I do have a Smarty Jr set on on tow and I leave it in that mode always. But apparently my right foot is not generating enough line pressure for the 48RE to make a good decision... or something like that. Anyhow, following the OD shift, the TC locks up and I do not recall it doing anything unusual. If my memroy is serving me correctly, the TC lockup would be shortly after the OD shift but not like, bam-bam. No what I mean? More like a second to possibly two second delay. The truck just rolled over 75,000 and I have changed fluid and filter three times since purchasing this truck new in 2003.

 

[LNaugle]

Good job cerb! guess you told him! lol! I would reccomend a suncoast complete valvebody and deep pan... once you run a suncoast valvebody nothing else is acceptable as far as i am concerned. BUT what do I know... .

 

[cerberusiam]

Yep, know just what you mean. If the TC doesn't lock right away under heay throttle and load its possible to drive right thru the TC on shifts. The TQ hit is huge on the OD shift and leverage plays right to it. Probably starting to see some wear in the TC if it is not new.

A 2-3 shuttle shift is pain. There are so many sources form the gov solenoid and transducer to leaks in the front servo to low line pressures it is hard to tell what the real problem is. A lot of times the flex bands stretch and the original setting does not work anymore oyu have to play with the setting to find a happy medium. TV pressure also gets lower with age and if you don't adjust the TV cable to hold the gear just a little longer it shifts too soon then bounces back.

Samrty reducing the TQ management usually raises havoc with the stock settings and you get shuttle shift by default. Have to compensate for more power with less throttle now.

 

[Alaskaskiff]

This is a really long thread and I tried to be diligent and read all of it before posting, but I still may have missed something. This may help someone if not already covered.

I also had an increasing coolant temp trend going on with my truck. With the temperatures what they are up here it is less noticeable. In any case, I noticed that the temp was about 1 needle higher empty and towing (19000 gcvw) and it was warming on hills, which it had never done before. I found a small leak from the water pump that had been slowly increasing. It was small enough that nothing ever hit the ground so I didn't see it at first. Due to other stuff with my espar heater I had changed coolant levels a couple of times so changes were less noticable. This whole sequence was over several thousand miles.

I replaced the pump and all is good now.

 

[Alaskaskiff]

This is a really long thread and I tried to be diligent and read all of it before posting, but I still may have missed something. This may help someone if not already covered.



I also had an increasing coolant temp trend going on with my truck. With the temperatures what they are up here it is less noticeable. In any case, I noticed that the temp was about 1 needle higher empty and towing (19000 gcvw) and it was warming on hills, which it had never done before. I found a small leak from the water pump that had been slowly increasing. It was small enough that nothing ever hit the ground so I didn't see it at first. Due to other stuff with my espar heater I had changed coolant levels a couple of times so changes were less noticable. This whole sequence was over several thousand miles.



I replaced the pump and all is good now.