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I had my transmission guy rebuild me a diesel transmission 4L80e for my 01 1500HD since my original trans the bellhousing ear was broken. plus all my hard part internals had signs of serious heat discoloration and surface cracks i gave him my orignal trans for a diesel trans with him installing the jakes performance rebuid kit. I already had the trucool 40k cooler with no thermostat control and i blocked off my stock radiator fittings for trans. trans has about 1800 miles on it, i live in ca and took a trip up to wrightwood and my trans was hitting 200F which was ok but when i got up a hill which wasnt very steep grade hill at all plus it was like 28F outside in snowing conditions my trans started to go up to 250F while my engine temp dropped from 205F to 150F i was just crusing up the hill at not even 15mph. whats going on?? i plugged in my snap on scanner to check for codes and look at the live data. the 1870 slip count was 0 at all times and TCC Slip Rpm was within specs from what circle D was telling me. the highest i saw on TCC Slip during full open throttle was near 800rpm slip and normal driving only got up to 500rpm slip. i did have the guy install the "shift kit" from Jake's but its still shifitng like stock feel. not sure if he enlarged the plate in the valve body. im running 20x12 wrapped on 33x12.50r20 tires. I'm planning on dropping the pan myself and correcting the shift feel to more firmer. i also dont have the heat shield that sits between the exhaust and transmission lines with my orginal trans wether i had that heat shield or not didnt make a difference in trans temp. what im going to do also is wrap the exhaust near the lines in exhaust wrapping to see if that changes anything. what should i do next? already dumped $2,700 into trans and a new torque conveter 2,200-2,400 stall. stock rear end gear ratio 3.73. even with my stock wheels i'd always have to stop on the pedal on the highways just to keep up.
what year trans core did you use?
Does it have one cooler line in the front and one in the middle of the case (97+ core)...if so, do you have the proper fitting in the rear? It will need an extension on the fitting to properly seal inside the center support.
If you have both cooler lines up front by the bellhousing (91-96 core) did the builder use the pump that was original to that trans, or did he need to use a different pump due to wear? If he used a new pump, there needed to be care taken to use a compatible pump. Year to year changes that aren't corrected can cause major issue.
I'm not sure what year core i will try to find out today and not sure if he used the pump that came with this trans or the one from my original. it does have the same location fittings as my original one and i'm not sure if he used the new fittings that came in my kit for that. I did order on amazon fragola npt to an fittings to go to an style fittings soon. I took some pictures of my transmission
That has the rear fitting for cooler oil
so it is 97+ case
need to ensure the fitting is correct, and if that is correct, next need to verify the pump is correct.
I'd be pulling the front cooler line and just checking for flow to be sure the cooler is seeing oil
yep! I've had this happen before.
I'll attach the PDF with all the info tonight.
Wrong pump mated to wrong case. The cooler has no flow going to it I bet.
unhook both cooler lines and fire it up. If it makes a huge mess then atleast you know that's good.
if not a drip comes out, you gotta pull. Trans and swap pumps at minimum. Hopefully your clutchs arent hurt too.
I do not currently have a tune on it just superchips tuner went with stock w/options just to get my speedo reading mph better I'm going check if i have flow right now and then check the fitting
So i removed the line and started it up the pressure line puked about quart and 1/4 of transmission oil in bout 5seconds at a steady flow now too much that the hose would fly out of the bucket i had it in. i also pulled the fitting and it threads nicley into case and appears to be the right fitting. i drove it and took me about half hour to try to get it up to nearly 200F to check fluid and i got a consisent reading of the lowest dot in hot level. before i had it at the highest dot level. didnt go over 200
Plug it back into the radiator cooler. The liquid will pull the heat out much faster than the air. especially at low speed when you don't have much air flow.
If you have good fluid flow and the torque is locking up I don't see how your getting 200* Temps with your setup.
I've got 33s and 4.10s in my 2500hd and even towing a 40' gooseneck yesterday with a F350 on it, I can't get my Temps over 150.
Im running the trucool 40k also and bypassing the engine radiator.
12-29-2021, 01:38 AM
01 1500HD 4L80E rebuilt "overheating" issues
