ZF 8hp70

Groppelt said:

Yes. I was in Tow/Haul mode. Temp crept up over about 20 minutes. I was pushing it. About 70mph and climbing hills but ever since it seems to be hot all the time. I might have the valve changed as well as a filter and fluid change. Not really sure if I want to go with the block off plate. Do you know if that would generate a check engine light?

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No check engine light with the block off plate. It's a passive system so the only thing the truck might do is keep the grill shudders closed (if you have them) to try to keep more heat in. I've yet to tow with mine, but I haven't seen a temp over 145 in the last couple months I've had the revmax kit installed.

I have a '17 Crew Hemi with 172k miles. The dealer says sealed for life but couldn't define "Life". I asked if that Fluid is good for 200k, 300k, etc. and no one could answer me..
I changed mine at 100k with Amsoil (which has the approval and the tech rep told me they would warranty it if I ever had a problem).
I did have to go back to the dealer to do a "Relearn" where they hook up the scanner and after about 500 miles it shifts perfect plus my temperature dropped about 10 degrees.

Groppelt said:

I know this has been asked before. I have a 2014 with the 8speed transmission and 5.7. Transmission is always at about 195 degrees. If I get stuck in traffic it goes up to 220 degrees. I was towing my 7000# camper and after an hour check engine light came on and temp was at 260. Brought it to the dealer and they said " sealed for life" and they didn't do anything. Service rep actually told me if I'm towing 7000# I should have a 2500! Doesn't seem right to me. Anyone have similar issue or any idea?

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The service rep is right, at 7000lb trailer tongue weight is around 1050lb so unless you put nothing in your truck you be over weight.

Now saying that my Express with 3.21 gears pulled my 7000lb trailer and I never went over 195 with my trans, even after a 3 hour drive going out west.

I since have traded my trailer and now have a 5000lb one as it was cheaper then buying a 2500. The 1500 is just not made to be pulling that weight and now pulling the new trailer the 1500 does not even know it there.

Trailer was actually #6700. Bought brand new from dealer and was towing it home. Totally empty. And yes, slowing down did help. Motor was more than capable though. Lol

Joe. Tongue weight was 700#. I also have the 3.92 rear gears.

regal81455 said:

For the most part I do all my own work too and generally speaking I don't really think about a dollar value for my time either but when discussing this it probably should be considered when figuring why it costs what it does from a shop point of view. That's just the commercial industrial GC in me though - always looking at the cost / value of something.

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one other thing to note, that $700.00 fluid change still leaves 50% or more of the old fluid remaining. with using the Redline fluid I was able to do 3 drain and fills to get rid of the most of the old fluid, along with a PPE pan for a lot less than 700 bucks.

MRFREEZE57 said:

one other thing to note, that $700.00 fluid change still leaves 50% or more of the old fluid remaining. with using the Redline fluid I was able to do 3 drain and fills to get rid of the most of the old fluid, along with a PPE pan for a lot less than 700 bucks.

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+1 on the PPE pan. Very nice pan indeed. It’s a PITA to press the stud collars into the machined aluminum as it’s super tight but can be done with some anti seize and patience. I elected to change my fluid early at 35k so not to worry about only getting half of the bad fluid out. I called ZF and spoke to a R&D engineer at length, he stated that all ZF 8 speed fluid is the same regardless of who’s name is on the bottle. You can get most Lifeguard 8 fluid branded with Audi or BMW for way less than Mopar 8&9 speed fluid. I’ve heard good things about Amsoil and Redline ATF as a substitute. The fluid change procedure isn’t as hard as it first appears, a pain in the butt, yes but not worth a $1000 dealer service.

"at 7000lb trailer tongue weight is around 1050lb"

Whoever set up your WDH and trailer loading did you no favors. Not that it is excessive as its in range but it is more load on your truck than need be. Even with a box front travel trailer at 65 mph 12.0 percent or 840 pounds put with a replaced steer weight is more than sufficient to stave sway, semi truck bow wave, or strong wind gusts. 10 percent or 700 pounds as Groppelt set his to is often sufficient.


"The 1500 is just not made to be pulling that weight"

That does not match what Ram engineers and or SAE Society of automotive engineers J2807 tow standards say. Both the tongue weight and the gross weight I can attest to with almost 800,000 miles towing TTs with the 1500.

In fact set up optimally with WDH according to CAT scale results the 4th gen 1500 platform (including proper gears & motor) can handle up to 8k well without exceeding axles, receiver, max tow or CVWR with the only exception being the least important with respects to stability & safety GVWR. This is good for OP to know as his 6,700 pound dry trailer will likely turn into 7,700 when camp ready.

Agree with other poster, what is Ram's idea of lifetime. ZF recommended fluid changes for dusty environments or hard applications such a racing or towing. I change mine every 100k with the Valvoline Maxlife full synthetic that meets this transmissions requirements as it's inexpensive in the gallon jugs. If you shop the filterpans online you can get them cheap now also. My first trans went 700k until a simple solenoid failed. Unfortunately it was built into the board and the dealership said $2,200 to fix. Instead I got a used 70k mile unit out of a salvage yard for $1260 plus simple swap labor. Its worked flawlessly for another 100k so far. If this has held up behind a 465 foot pound torque tuned Ecodiesel it should do well behind a 410 torque Hemi. Both trucks use the 3.92.

When I tow the whole day I end up stopping one less time for fuel towing at 65 vs 70 mph. What I gained on the road I lost sitting at the fuel pump. Its not as hard on the truck in general.

Ram_Bobby said:

What about an additional trans fluid cooler?

Also, I don't mean to bust on the original poster, but could it be 70 MPH up hill with a 7K pound camper might be too much? I don't regularly tow, but when I do, set the cruise on like 65MPH, just stay in the right lane and keep the screen on the trans temp constantly.

Was the trailer 7K before loading it? Might have been pulling more? Just some thoughts.

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I have one of Caulk04's units in my 8HP45 behind a Pentastar with 3.21 gears. Last weekend I towed a 73 International Harvester 3/4 ton camper special 750 miles through the mountains and hills of SC, NC, VA, WV, and OH. I never lost speed on hills although the little 3.6 was singing on some steep upgrades, and the transmission temperature never went higher than 170. Engine temperature and oil temps got up to around 220 at times, but even that wasn't worrying. I have the shutters deleted, between that and the transmission thermostat mod I'm very happy with how my truck handled a tow it shouldn't have made. IMHO, the factory cooler is plenty....but the shutters and factory transmission thermostat are the causes of high temps.

Ram_Bobby said:

What about an additional trans fluid cooler?

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This could certainly help keep temps from going nuts way over 200, but it won't get you anything below the stock thermostat temp so you're running 175-180 at least.

olscout, I too agree with Bobby that 70 uphill with a 7k TT is working things hard. On another note and fwiw I do not know what your camper special looks like or weighs. I do know the naturally aspirated and small displacement of the 3.6 fully utilizes the 8 speed to make up for the torque that it does not have. 269 vs 410 means it won't turn the taller gear but might be able to make up for it by running a lower gear and spinning it harder. More torque puts more load on the transmission which in turn generates more heat in a transmission. So I'm not sure that the Pentastar is good for comparison here. But I'm all for trans coolers.

Atcer2018 said:

+1 on the PPE pan. Very nice pan indeed. It’s a PITA to press the stud collars into the machined aluminum as it’s super tight but can be done with some anti seize and patience. I elected to change my fluid early at 35k so not to worry about only getting half of the bad fluid out. I called ZF and spoke to a R&D engineer at length, he stated that all ZF 8 speed fluid is the same regardless of who’s name is on the bottle. You can get most Lifeguard 8 fluid branded with Audi or BMW for way less than Mopar 8&9 speed fluid. I’ve heard good things about Amsoil and Redline ATF as a substitute. The fluid change procedure isn’t as hard as it first appears, a pain in the butt, yes but not worth a $1000 dealer service.

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yes the collars were a bit difficult to press in, I reamed a few of the holes that were extra tight but once in they are in. what I like the best about the PPE is when doing your follow up drain and fill the drain plug is easily accessible, not right under the exhaust cross over as with the plastic pan.
I had never serviced an automatic transmission before doing the Ram and it was not bad at all, the most difficult part was raising up the rear end to get the transmission level.

MRFREEZE57 said:

yes the collars were a bit difficult to press in, I reamed a few of the holes that were extra tight but once in they are in. what I like the best about the PPE is when doing your follow up drain and fill the drain plug is easily accessible, not right under the exhaust cross over as with the plastic pan.
I had never serviced an automatic transmission before doing the Ram and it was not bad at all, the most difficult part was raising up the rear end to get the transmission level.

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LOL yes getting the transmission level is the hardest part. I have a 4WD and at stock height most floor jacks barely have the lift to move the suspension upward when jacking from the rear axle. I tried putting scrap 2X8 pieces under the jack but still couldn’t get enough lift to level the transmission. I even let air out of the front tires while the rear was raised to get it level. Then my jack stands didn’t have the extension to support the raised height. Frustrated I sat contemplating my dilemma, my daughter who is an engineering student says dad just back it up the driveway so the front is on the down slope until it’s level! I saved a lot doing DYI but it does cost me $20k per year for the technical advice. LOL

Atcer2018 said:

LOL yes getting the transmission level is the hardest part. I have a 4WD and at stock height most floor jacks barely have the lift to move the suspension upward when jacking from the rear axle. I tried putting scrap 2X8 pieces under the jack but still couldn’t get enough lift to level the transmission. I even let air out of the front tires while the rear was raised to get it level. Then my jack stands didn’t have the extension to support the raised height. Frustrated I sat contemplating my dilemma, my daughter who is an engineering student says dad just back it up the driveway so the front is on the down slope until it’s level! I saved a lot doing DYI but it does cost me $20k per year for the technical advice. LOL

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it would be so simple if it had a dip stick. recently did a fluid change on my 2011 Ford Fusion, so simple. drain the fluid, refill thru the dip stick tube, run till hot and adjust level between the add/do not add level.
my personal choice for a truck is it would have a stick shift on the floor and a clutch pedal but they do not exist on a 1500 class truck any more.

VernDiesel said:

olscout, I too agree with Bobby that 70 uphill with a 7k TT is working things hard. On another note and fwiw I do not know what your camper special looks like or weighs. I do know the naturally aspirated and small displacement of the 3.6 fully utilizes the 8 speed to make up for the torque that it does not have. 269 vs 410 means it won't turn the taller gear but might be able to make up for it by running a lower gear and spinning it harder. More torque puts more load on the transmission which in turn generates more heat in a transmission. So I'm not sure that the Pentastar is good for comparison here. But I'm all for trans coolers.

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Sorry I wasn't more clear. I was towing a 73 IH 3/4 ton camper special pickup truck on a car trailer. Truck is probably +-5,000 pounds. Trailer is an 18' with 2' dove, 83" between fenders, treated wood deck, guesstimate 1700 pounds. And plenty of hills. My point was that the stock cooler can do the job if you delete the shutters and the thermostat. Putting an additional cooler on with the shutters still in place won't accomplish much of anything without airflow.