Transmission issues??
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Transmission issues??
Hi Y'all
I am new to this forum- I have a 1999 F250 superduty 7.3 200000 miles with original 4R100 transmission. Recently tranny has been getting hot about 225 F so i rebuilt the bypass with
Still was running hot so i am getting a bigger cooler (replacing the 7.3 cooler with a 6.0 cooler- more vanes)
I have also noticed just recently that when tranny gets hot about 200 F when i put it in reverse and give it a little fuel it will die-- if i give it a lot (RPM over 1500) then it will run and not die.
My question - Is this a transmission or torque convertor issue. I did a stall speed test and truck would not go over about 1500 RPM for two sec. test ( was concerned about transmission damage) but did not stall.
BTW the transmission is heating up with no towing or extra weight.
Thanks for any help
I am new to this forum- I have a 1999 F250 superduty 7.3 200000 miles with original 4R100 transmission. Recently tranny has been getting hot about 225 F so i rebuilt the bypass with
- 36605-02K - Sonnax E4OD 4R100 Transmission Cooler Bypass Valve Kit 36605-02k
Still was running hot so i am getting a bigger cooler (replacing the 7.3 cooler with a 6.0 cooler- more vanes)
I have also noticed just recently that when tranny gets hot about 200 F when i put it in reverse and give it a little fuel it will die-- if i give it a lot (RPM over 1500) then it will run and not die.
My question - Is this a transmission or torque convertor issue. I did a stall speed test and truck would not go over about 1500 RPM for two sec. test ( was concerned about transmission damage) but did not stall.
BTW the transmission is heating up with no towing or extra weight.
Thanks for any help
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Joined: May 2014
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@Big_Red99 welcome to the FTE!
You might find our 7.3L PSD Tech Folder of use to you as you travel throughout the forum. The Tech Folder can be found at the link below.
7.3L PSD Tech Folder
Also, I found this tidbit of information from Mark K who is our resident Ford Transmission engineer.
You might find our 7.3L PSD Tech Folder of use to you as you travel throughout the forum. The Tech Folder can be found at the link below.
7.3L PSD Tech Folder
Also, I found this tidbit of information from Mark K who is our resident Ford Transmission engineer.
Originally Posted by Mark Kovalsky
These transmissions run 60-100°F above ambient. They can run 220°F all day long with NO problems. Your fluid is NOT burned from running 220°F.
The main problem with the early trucks is that they didn't have a cooler in the radiator and the air to oil cooler wasn't big enough, either.
The fluid will start burning above 400°F. That's not a typo, I said above four hundred degrees Fahrenheit.
Ford specs say it can run all day long with NO problems up to 220°F. You can go up to 250°F for no more than 1/2 hour at a time. If you get above 250°F you should find a safe place to stop and idle or fast idle in park or neutral to cool the trans.
The continuous maximum temperature is 221F, and the maximum for no more than 1/2 hour at a time is 252F.
210F towing 20k pounds is normal. If the bypass were not working right that trans would be really hot.
The main problem with the early trucks is that they didn't have a cooler in the radiator and the air to oil cooler wasn't big enough, either.
The fluid will start burning above 400°F. That's not a typo, I said above four hundred degrees Fahrenheit.
Ford specs say it can run all day long with NO problems up to 220°F. You can go up to 250°F for no more than 1/2 hour at a time. If you get above 250°F you should find a safe place to stop and idle or fast idle in park or neutral to cool the trans.
The continuous maximum temperature is 221F, and the maximum for no more than 1/2 hour at a time is 252F.
210F towing 20k pounds is normal. If the bypass were not working right that trans would be really hot.
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Thanks- yes i have seen that post- but my tranny was running under 180 F consistently and now after 20 miles it will jump to 200 to 250F. But troubling thing is the deal with the reverse, weird it clunks then dies- oh forgot to mention i also did a stall speed test for just about 2 sec - got nervous- and RPM got to about 1500 and would go no higher- another reason i think it might be problem with torque converter.
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,731
Likes: 2,658
From: SE Florida
It's probably worthwhile to run a cooler flow test.
Warm the trans up. It should be at least 150°F.
Have two containers, each at least one gallon.
Get a hose that will fit over the cooler return line at the rear of the trans.
Remove the return line where it enters the rear of the trans.
Put the hose on the return line and put it into container #1.
Have a helper start the engine and leave it in park and at idle.
When the flow is steady out of the hose (that should only take a few seconds) move the hose to container #2 for EXACTLY 15 seconds, then put it back in container #1.
Shut the engine off.
Results:
If fluid sprayed out of the transmission, the test fails. A small dribble is fine, but spraying is not.
If there is less than a quart in container #2 the test fails.
If the test fails either the cooler bypass valve is stuck open or there is a restriction in the cooler circuit.
Warm the trans up. It should be at least 150°F.
Have two containers, each at least one gallon.
Get a hose that will fit over the cooler return line at the rear of the trans.
Remove the return line where it enters the rear of the trans.
Put the hose on the return line and put it into container #1.
Have a helper start the engine and leave it in park and at idle.
When the flow is steady out of the hose (that should only take a few seconds) move the hose to container #2 for EXACTLY 15 seconds, then put it back in container #1.
Shut the engine off.
Results:
If fluid sprayed out of the transmission, the test fails. A small dribble is fine, but spraying is not.
If there is less than a quart in container #2 the test fails.
If the test fails either the cooler bypass valve is stuck open or there is a restriction in the cooler circuit.
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HI Mark
I tried the cooler test - and there is no restriction after i put in the larger 6.0 cooler
. I still have a hard shift into 4th(?) gear. Still curious as to how to test the Torque converter- guess i should try the speed stall test again since i got cooler issue solved. I am also going to use Transgo 4R100HD2 Reprogramming Kit for 4R100 to see if it helps shifting. I will also tighten the feed bolts as per some of your earlier advice while i have the pan dropped.
Any other advice would be helpful and I do apologize if you have already listed these on the forums.
Thanks
I tried the cooler test - and there is no restriction after i put in the larger 6.0 cooler
. I still have a hard shift into 4th(?) gear. Still curious as to how to test the Torque converter- guess i should try the speed stall test again since i got cooler issue solved. I am also going to use Transgo 4R100HD2 Reprogramming Kit for 4R100 to see if it helps shifting. I will also tighten the feed bolts as per some of your earlier advice while i have the pan dropped.Any other advice would be helpful and I do apologize if you have already listed these on the forums.
Thanks
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Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,731
Likes: 2,658
From: SE Florida
The only in truck test for the torque converter is the stall test. The only other way I know to test the converter is to take the converter out of the truck and take it to a shop that has a torque converter dynamometer. It's probably cheaper to just buy a new converter than to dyno test the one you have.
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Hi Y'all
When it stalls it would just quit, no real lunge,but can report that after got the transmission heating to stop going over 200 deg the reverse seems to work with no stalling. Also discovered I was at least a quart low on transmission fluid and when i added more my shifting improved (mea culpa
should have checked that earlier). I will try the stall test again.
I am so excited
that the new cooler works- my original one must have been clogged. Yes it flowed a quart on new flow test.
Thanks for all the feedback will report back on new stall test.
Another weird thing is that my fuel pressure had been reading low on my gauge inside the truck-electric type gauge, thought the fuel pump might be going out ( still has the original bosch inline pump)- and now after got cooler fixed it seems to be normal--- coincidence or is my truck just happier now? Of course sh_t could still happen.
When it stalls it would just quit, no real lunge,but can report that after got the transmission heating to stop going over 200 deg the reverse seems to work with no stalling. Also discovered I was at least a quart low on transmission fluid and when i added more my shifting improved (mea culpa
should have checked that earlier). I will try the stall test again.I am so excited
that the new cooler works- my original one must have been clogged. Yes it flowed a quart on new flow test. Thanks for all the feedback will report back on new stall test.
Another weird thing is that my fuel pressure had been reading low on my gauge inside the truck-electric type gauge, thought the fuel pump might be going out ( still has the original bosch inline pump)- and now after got cooler fixed it seems to be normal--- coincidence or is my truck just happier now? Of course sh_t could still happen.
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