Longtime since I have been on the this forum. The 01 GP still going strong with the 3.1 V6 and OEM 4T65E at 225,000 miles..ZERO ISSUES. I am no changing the fluid and filter every 10,000 miles, about once per year. The stand alone double stack Dana coolers still do all the cooling and the fluid looks great at every change with little sentiment in the pan. USE DEXRON VI, not III, since VI is a much better fluid and backward compatible to our tranny's. My 4T65E called for Dexron III in 2001 and I have been using VI since 60,000 miles, ZERO ISSUES, for Oh, 160,000 miles......Whatever happened to the "genius" GP tranny and car "experts" who all claimed the the transgo shift kit and the external coolers only (no radiator cooling) was a temporary fix for the hard shift issue? Just wondering.....
High mileage transmission, change fluid or not?
- Thread starter NotEnoughGPs
- Start date
Thanks. I recently developed the hard shift issue for 1-2 and 2-3 after my trans fluid quickly turned dark and was bubbling after 115k. Did a pan drop, filter change, 1 bottle of Lucas Trans Fix, and added about 7 qts of Dex VI. The problem improved, but it still occasionally occurs. Now at 125k and fluid looks good, and otherwise without the occasional hard shifting in low gears the trans shifts great. Reading through all the trans related threads and I'm thinking of installing a trans cooler next. Reading through the info, it seems better to put the cooler after the stock cooler and not stand alone. Not sure about a shift kit yet. Will try cooler first and then take it from there.
I have had 2 long Dana/Long Double stack coolers 18,000 GVW Each, 36,000 GVW total, OUTSIDE of the radiator cooling since around 88K (Car is now at 225K). You want to keep the trans fluid as cool as possible (mine runs around 150 degrees in the hot summer weather and around 120 125 Degrees in very cold winter weather (around 15-25 degrees). Long/Dana coolers have automatic temp control built into the double stack design. To eliminate the hard shift issue you will need the external coolers (I have been running the coolers as stand alones, no radiator cooling, on many cars for the last 40 years and have NEVER had a tranny failure on any car. You will need a transgo shift kit for the 4T65E if you want to totally eliminate the hard shift issue. My tranny has been perfect for the last 140,000 miles with no issues running the aforementioned coolers, Shift kit and Dexron VI...
Those temps seem really low, much lower than other examples I've seen posted here. Think I read somewhere here that trans needs to be at least 77 or so degrees for torque converter lockup and that using a standalone cooler takes longer to warm up the trans. Won't matter to me as long as I can get rid of the hard shifting though.
Scottydoggs
Killa Bee
that is to cold. to cold can be as bad as to hot. 170-180 is best.
I recall seeing several posts here about too low temps. Also, having too low trans temps is discussed on general automotive discussion sites too. I believe I saw around 177 degrees as the minimum temperature quoted on this forum (forgot the 1 in front of the 77 degrees in my post above).
Scottydoggs
Killa Bee
i figured a digit was missing lol
it need to get hot enough to steam off any condensation as i understand it, to cold and your gonna have some water build up inside the tranny.
BrandonHall10
Solving problems
Yep. I've rebuilt some that had oversize coolers on them. Every bit of ferrous metal was rusted.
Wow. That is important information.
I'm rethinking my priorities after reading through the posts again. I wasn't going to do a shift kit at first, but it appears that the shift kit can do more to actually fix the problem than a trans cooler. The trans cooler is more like insurance, while the shift kit can remedy the problem better. So I may want to do the shift kit first, then the trans cooler.
The temps are NOT too low...The ideal temp is around 140 but achieving that temp is next to impossible in warm weather. Last call for me, I have been doing this for 40 years with zero issues on many cars and zero tranny failures ever. Change the fluid and filter no more than every 10-20k miles along with the coolers (I highly recommend stand alones based on the 100's of thousands of miles I have done this way) and you will get tremendous life from these tranny's along with the shift kit.
The tranny does need to reach 88 degrees for overdrive BUT I have no issues in the winter other than it takes a few miles for the OD to engage.
You do what you want but I am giving advice that WORKS from practical experience over MANY years and thousands of miles...no theory here.
The tranny does need to reach 88 degrees for overdrive BUT I have no issues in the winter other than it takes a few miles for the OD to engage.
You do what you want but I am giving advice that WORKS from practical experience over MANY years and thousands of miles...no theory here.
Not taking sides here. Just trying to figure out the best course of action by evaluating the information provided. There isn't 100% agreement regarding the situation so it can be a bit confusing. Also, as with anything else, there are usually multiple ways to solve problems, especially with so many variables are involved such as driving habits, vehicle age and condition, maintenance performed, driving terrain, weather conditions, etc.
BrandonHall10
Solving problems
Off topic. My apologies to the OP.
@jbamonte: Let me start by saying I am not arguing with you. I'm asking this question for my own edification. Please correct me if any of this is wrong.
The 4t65e has an internal thermal element that limits/restricts fluid flow to the cooler at temps below (around) 160°. What is the purpose of this thermal element if not to maintain a minimum fluid temperature?
BrandonHall10
Solving problems
Well shoot. I was really hoping to learn something.
Okay then. You keep your secrets.
Okay then. You keep your secrets.
I have never heard of the internal temp control on the 4T65E and I have not had any issues with fluid flow or too low fluid temps in the last 140,000 miles that I have had the dual Dana/Long 18,000 GVW Double stack coolers on the car. The Long coolers have automatic temperature control built into the design that limits Trans fluid flow to the coolers based on viscosity..thicker fluid (cooler) and less goes to the coolers, Fluid viscosity thinner (warmer) and more fluid flows through the coolers. There are no temp/fluid flow issues using stand alone coolers on these transmissions.
BrandonHall10
Solving problems
ATSG #121 THERMO ELEMENT and ATSG #122 THERMO ELEMENT ORIFICE PLATE
I'm not saying the transmission won't function fine UNDER 160°, I'm just curious why the engineers at GM added cost and complexity to a transmission if it didn't serve SOME purpose.
BrandonHall10
Solving problems
WRONG! I know this is an old thread, but I don't like misinformation like this floating around. There is a definitive answer to ideal ATF temperature and "as cool as possible" is not it. In this interview, Jake Shoemake from Jakes performance gives the ideal trans temp range AND the reason why it is important to hit that range. Moisture, cavitation, filter restriction...
Sloppy Radio Show EP05 - Jake (Jake's Performance) - YouTube
Your transmission may appear be "fine" with 140k miles on it, but you can't say that with certainty until you pull it apart an inspect. Especially the pump faces.
AGAIN, you do what ever the heck you want BUT I am giving you real life practical experience on many transmissions over 100's of thousands of miles (read that again in case you missed this point) running BIG GVW rated coolers as stand alone coolers, outside of the radiator cooling, AND have NEVER had a transmission failure or ANY issues whatsoever! You can argue, make your point, call my view point different BUT it is most definitely NOT wrong or incorrect!
I am at 225,000 miles on the 4T65E and about to do the routine filter and fluid change (Dexron VI, and no, Dexron VI will not harm these trannies as many of the "experts" said back 15 years ago!). The fluid color and pan ALWAYS look perfect. If running very low tranny temps is so bad then why has not my transmission failed yet and why does the fluid always looks so good with zero ferrous metals in the pan? I'll wait for an answer.
Go back to the very beginning of this post YEARS ago and read some "expert" comments about what I have been saying for over 10+ years was wrong/incorrect. Don't look foolish and mimic the nitwits from the past. Most these clowns were more wrong then right and thankfully have disappeared from this forum. Good Riddance!!!
I am at 225,000 miles on the 4T65E and about to do the routine filter and fluid change (Dexron VI, and no, Dexron VI will not harm these trannies as many of the "experts" said back 15 years ago!). The fluid color and pan ALWAYS look perfect. If running very low tranny temps is so bad then why has not my transmission failed yet and why does the fluid always looks so good with zero ferrous metals in the pan? I'll wait for an answer.
Go back to the very beginning of this post YEARS ago and read some "expert" comments about what I have been saying for over 10+ years was wrong/incorrect. Don't look foolish and mimic the nitwits from the past. Most these clowns were more wrong then right and thankfully have disappeared from this forum. Good Riddance!!!
^^^^"Most of these clowns were more wrong, then right and thankfully hasve disappeared from this forum. Good Riddance!" edit correction