8hp70 heater bypass

[olscout]

Well, I am the middle of doing this and that damn black plastic cap housing does not want to come out. There aint much left of that nipple with me trying to grab it with some pillars. lol
Yes the snap ring is off.

Might try another time with a spare black cap.

I had a time getting mine out too. I ended up using a small wire brush to get the white oxidation between the housing and the steel snap ring, then shot it with penetrating oil. Pushed it in, worked it out a little, back in, after a few repeats it came out. Putting it back in was easier except now it wouldn't stay in, had to hold it in and replace the snap ring at the same time.

 

[Wild one]

Rick Spillman. Don't get me wrong, I'm not trying to speak ill of him.

O-ya i know him,i also think that 8 speed in his truck,just might have a few issues that might have more to do with the fact the tranny see's 7,000+ constantly with a huge convertor,plus i'm not so sure his tuner is all that good especially in regards to transmission tuning. Now that i know who's doing the ********,i'm not to worried anymore,lol.Plus i know the majority of guys with built engines ahead of the 8HP70 try to get the tranny and engine as cool as possible before their first run,as you're always going to get the best numbers out of a Hemi on it's first pass when everythings cooled off. I've been known to beat the **** out of the wifes 1320 when the tranny is only 100F,and on drag mode it shifts at 6400 rpm,plus i beat the hell out of my trucks 8 speed constantly when it's at 130 to 140F,and it shifts at 6500 on the drag tune.

 

[olscout]

Since I sold my beater Avalanche the other day (tax refund + stimmy money= fast sale) I've been driving the Ram. Yesterday was 65 ambient and a lot of in town, sitting in drive throughs, etc. With basically not moving, engine and oil temps were over 200, and the transmission temp climbed to 172 at the highest. Once I was on the road driving home, it came down to 150 pretty fast. I'm not really sure how this heater setup works, but my guess is that while sitting, the transmission isn't moving as much fluid as it does in the road, giving it more dwell time in the heater, plus no air moving through the cooler. Today it was 60 ambient and it was all county roads and highways, speeds 55-70 mph. Temp stayed right at 130. I'm not worried about too low of temperature, ZF didn't develop a super secret high temperature juice made from unicorn horns just for the 8hp transmissions. They're using similar fluid to everyone else, and it's as prone to thermal breakdown at 220-240 temps as fluid in any other transmission. I'm out of warranty, so I'll do what I think is best for longevity. Heat has always been the enemy of oil, and synthetics, although an improvement, aren't a cure all.

 

[grizzstang]

I’m having caulk send me back my tstat. Been doing a good bit of research into these transmissions. BMW runs the same 8hp in their cars and are actually running them around 200-220° and use a fluid heater setup just like our rams. A few other manufacturers use similar setups and run them around 190-200°. I am planning on pulling out the threaded plugs and installing -6 AN fittings and tubing to replace the pathway that the heat exchanger was. Caulk is sending me one of his delete plugs as well in case I end up wanting to go back to full cooler flow. Supposedly some of the 8hp90s are having issues with torque management until they are over 160° I may try and see if I can buy the 160° that paramount offers

Other manufacturers might be trying to squeak that miniscule fuel mileage gain by running the trans hotter than required too.

The world demands it. We are all going to die in the next 10 years, at least that is what they have been telling us since the early 70's.

If the trans needs to run that hot I would be curious as to why FCA doesn't put the heater on everything with the 8 speed.

 

[18GSMRam]

Other manufacturers might be trying to squeak that miniscule fuel mileage gain by running the trans hotter than required too.

The world demands it. We are all going to die in the next 10 years, at least that is what they have been telling us since the early 70's.

If the trans needs to run that hot I would be curious as to why FCA doesn't put the heater on everything with the 8 speed.

Maybe the quote of the day.... why is it good for goose but not the gander? Does.Not.Compute.

 

[18GSMRam]

One thing I have been tossing around in my head, some of you may have brought it up, but I haven't seen it....

There are some concerned that the temps could be too low with a complete bypass, why not remove the heater and the 3way valve (or in conjunction with) and install the bypass that is in the cars?

You get the best of both worlds, 20 degree lower temps (160) and it won't ever get down too low for the colder climate folks

 

[crazykid1994]

One thing I have been tossing around in my head, some of you may have brought it up, but I haven't seen it....

There are some concerned that the temps could be too low with a complete bypass, why not remove the heater and the 3way valve (or in conjunction with) and install the bypass that is in the cars?

You get the best of both worlds, 20 degree lower temps (160) and it won't ever get down too low for the colder climate folks

Without custom work to the lines that’s not possible. I’ve debated on taking it to my local shop and have them flare the lines for me to do that but don’t really want to put my truck up on a flatbed.

 

[18GSMRam]

Without custom work to the lines that’s not possible. I’ve debated on taking it to my local shop and have them flare the lines for me to do that but don’t really want to put my truck up on a flatbed.

Why not use hose instead of hard lines?

 

[Wild one]

One thing I have been tossing around in my head, some of you may have brought it up, but I haven't seen it....

There are some concerned that the temps could be too low with a complete bypass, why not remove the heater and the 3way valve (or in conjunction with) and install the bypass that is in the cars?

You get the best of both worlds, 20 degree lower temps (160) and it won't ever get down too low for the colder climate folks

I think the majority of cars use a 180 tranny t-stat,the heavy duty trucks with the 8 speed might work,and i think the 1320 Challengers might have a lower T-stat,as they're the only factory 8HP70 with a high stall convertor and tranny brake,plus they have differant shift mapping from a normal 6.4 Scatpack (similiar to a Demon). Be easier to use Improved Racings T-stats you can get them in a variety of temps but the 2 that would be interesting are their 145 and 165 versions,and they can be had with hose ends,while the factory t-stat would take some screwing around to come up with a hose end,unless you found one off a heavy duty truck in a wrecking yard,and the 8 speed equipped HD's are still new enough,they'd probably want to sell you the whole transmission just to get the lines and t-stat. Look close at Hellraiser's pic,you'll see you'd need the lines off it to,then look at Improved Racings T-stat.

You'd probably need several inches of the factory hardlines lines to make this work in a 1500
ZF8HPXX Thermostatic BY-PASS Valve — Hell Raiser Transmission LLC.

This one could probably be spliced into the rubber hose part of the factory cooler lines on a 1500.
High-Flow Engine & Transmission Oil Cooler Thermostat (improvedracing.com)

 

[crazykid1994]

Why not use hose instead of hard lines?

Still would need to flare the hard line or cut the rubber lines like Wild one is saying. Im not a fan of cutting the rubber lines.

 

[Wild one]

Still would need to flare the hard line or cut the rubber lines like Wild one is saying. Im not a fan of cutting the rubber lines.

Cutting the rubber hoses ,and plumbing in the Improved Racing thermostat with hose barbs wouldn't bother me as much as cutting the hardlines and trying to get the factory nipple ,plus flairing the lines after installing the factory nipple.The factory nipple appears to use a 20 mm wrench,so i'm guessing it might be a metric nipple.I have nothing against rubber hoses and hose barb fittings with a band style hose clamp,used them lots over the years with no issues

 

[18GSMRam]

I think the majority of cars use a 180 tranny t-stat,the heavy duty trucks with the 8 speed might work,and i think the 1320 Challengers might have a lower T-stat,as they're the only factory 8HP70 with a high stall convertor and tranny brake,plus they have differant shift mapping from a normal 6.4 Scatpack (similiar to a Demon). Be easier to use Improved Racings T-stats you can get them in a variety of temps but the 2 that would be interesting are their 145 and 165 versions,and they can be had with hose ends,while the factory t-stat would take some screwing around to come up with a hose end,unless you found one off a heavy duty truck in a wrecking yard,and the 8 speed equipped HD's are still new enough,they'd probably want to sell you the whole transmission just to get the lines and t-stat. Look close at Hellraiser's pic,you'll see you'd need the lines off it to,then look at Improved Racings T-stat.

You'd probably need several inches of the factory hardlines lines to make this work in a 1500
ZF8HPXX Thermostatic BY-PASS Valve — Hell Raiser Transmission LLC.

This one could probably be spliced into the rubber hose part of the factory cooler lines on a 1500.
High-Flow Engine & Transmission Oil Cooler Thermostat (improvedracing.com)

I could have sworn I read somewhere that the car valves open up around 160... Interesting well if they are truly 180 then yeah no sense.

The improved racing item looks like a potential good solution..... Who is gonna be the test dummy?!

Still would need to flare the hard line or cut the rubber lines like Wild one is saying. Im not a fan of cutting the rubber lines.

Flarring kits arent terribly expensive last I knew at least for the size of the stock hard lines. Whether or not you can get the tool up in there to flare while still on the truck is another question.

Could use mobile hose solutions and custom fab hoses on the spot using fittings that would screw right into stock fittings on the hard lines. Not sure what that would cost but I know in a past life when hoses would blow in the field and getting a replacement wasn't possible this was the route taken and was always reasonably priced according to the owner then again it wasnt my money and equipment being down is super expensive when considering time lost

 

[Wild one]

One thing I have been tossing around in my head, some of you may have brought it up, but I haven't seen it....

There are some concerned that the temps could be too low with a complete bypass, why not remove the heater and the 3way valve (or in conjunction with) and install the bypass that is in the cars?

You get the best of both worlds, 20 degree lower temps (160) and it won't ever get down too low for the colder climate folks

Yes it's been brought up,i mentioned it in the long RevMax thread it's also where i posted a link to Improved Racings thermostat and said it might be the way to go for the guys who wanted a little more heat and faster warm-ups in their 8 speed 1500's. Not the first time i've posted a link to them either,lol

 

[Wild one]

I could have sworn I read somewhere that the car valves open up around 160... Interesting well if they are truly 180 then yeah no sense.

The improved racing item looks like a potential good solution..... Who is gonna be the test dummy?!



Flarring kits arent terribly expensive last I knew at least for the size of the stock hard lines. Whether or not you can get the tool up in there to flare while still on the truck is another question.

Could use mobile hose solutions and custom fab hoses on the spot using fittings that would screw right into stock fittings on the hard lines. Not sure what that would cost but I know in a past life when hoses would blow in the field and getting a replacement wasn't possible this was the route taken and was always reasonably priced according to the owner then again it wasnt my money

Yea i wouldn't trust compression fittings in this scenerio,they'd probably be okay,but you'd want to be checking them fairly often.You didn't read anything about 160,you seen it mentioned on Webbers video,and i have issues with that video,as nowhere do they lift the tires off the ground so the vehicle makes the shift into 2nd gear,and his ideas on having to drive the vehicle till the thermostat opens then recheck the level i question,but you and i have already had this conversation and i'm not about to revisit it again,just know that video leaves a ****load to be desired.
Odds are you'd need a 37 degree A/N flairing kit,as i'm not sure the fittings would use a standard 45 degree flair,.

 

[18GSMRam]

Ha agree, anyway you posted about that Improved Racing cooler before so that's good, food for thought for some wanting an inbetween of stock and complete removal of stock thermostat.

I'm happy with complete removal so no plans to explore more from my end

 

[BlownGP]

I had a time getting mine out too. I ended up using a small wire brush to get the white oxidation between the housing and the steel snap ring, then shot it with penetrating oil. Pushed it in, worked it out a little, back in, after a few repeats it came out. Putting it back in was easier except now it wouldn't stay in, had to hold it in and replace the snap ring at the same time.

Some more good advice. Thanks
I'm going to give it a shot again this weekend if I have time. Want to get it installed before my road trip next month.

 

[CAPnHarley]

Got mine the other day had to find a way for a fat man to get underneath the truck and install it. Accomplished said task and made an 800 mile drive temps never got over 168 had previously hit 230+ on long drives. Very pleased.

only concern I have now is the truck has 117k miles on it and transmission was serviced about 15k miles ago. I afraid they might have used wrong fluid and dealerships around me will not touch it unless there is a fault being displayed.

 

[Bigskyroadglide]

Just made another Nashville to Central Virginia run, truck performance was great.

Here is Trans temp, on a 76 degree day running around 70 in freeway traffic with the air conditioning system on and cooling

I have not modified it yet with the brass valve from chalk. Will be undertaking this project when I change Trans fluid

 

[caulk04]

I'm really curious what you'll find in that thermostat housing. Some factory freak or something.

 

[caulk04]

'YoU'rE tRaNs WiLl RuN tOo CoOl'

Lol, had to.

View media item 30957