Thermostat thought...

[Chevy1925]

260*+ trans temps ain't "warm temps" lol. They would continue but I kick it out of gear and use truck/trailer brakes from there

 

[JoshH]

James, are you still running an LB7 turbo?

 

[Chevy1925]

Yes sir.

 

[JRein]

260*+ trans temps ain't "warm temps" lol. They would continue but I kick it out of gear and use truck/trailer brakes from there

Sorry on my phone and can't see signature, what type of pressure you running in the Allison?

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[Chevy1925]

Sorry on my phone and can't see signature, what type of pressure you running in the Allison?

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T-stats will not be coming out nor will I put restrictors in. For one, you would have to block the water pump bypass tube to do restrictors and second, the orifice size is very particular. I don't want to be running up and down hills all summer just trying to get that figured out.

She gets driven more in the winter here than summer between dune trips and nice cruises, it's generally when I drive it the most but I don't hit the hills I do in the summer. There are two short 6% grades that I can pull in 5th gear and temps don't even move till I'm cresting the top lol. Summer is the killer on my truck

There are no check balls in these t-stats, just a bleed hole in each

Converter is locked the whole time. Like josh said, my built trans, heavy weight and high rpm is getting it hot. Iirc the trans pressures are in 320psi range.

I don't want to drill holes. I've done that in other vehicles and it just prolongs warm up time. Plus I don't think that's going to be enough water. I already have the turbo return to the top of the thermostat housing so that is a decent amount of water circulating around the thermostat

Not tying to be negative to these ideas so sorry if that's how it's coming across. It's stuff I've tried before on other rigs and I know the down falls to them already. Only thing I have not seen is someone trying a thermostat setup like I was thinking. This is also assuming the engine doesn't cool its self down enough to the point the 160* stat closes too lol

Not in the sig, posted it here a while back

 

[JoshH]

Have you thought about swapping to an LLY turbo? I know you would have to make some changes to your plumbing, but that shouldn't be much of a problem for someone with your fab skills.

 

[Chevy1925]

Yup, it's been on the back burner to do for some time. It's just not been a high priority. I was more concerned with coolant temps and was hoping this would help trans temp along the way. I know what I want to do for a lly turbo, I'm just waiting for Russel and my buddy Jon to get their butts in gear and try it before I do it lol.

Or I just bite the bullet and do a 68stg2r. Maybe this late spring/summer

 

[JoshH]

I thought you already had an LLY turbo in it. I bet that will be enough to let you keep the rpm below 3000 which will probably keep the temps more reasonable.

 

[BlkMax]

What about adding an electric pusher fan for the trans cooler? Force the trans cooler to work.

I have had similar problems in AK, where I can get high trans temps at idle or in traffic but NEVER get the fan clutch to engage because of lower ambient air temps (that problem was solved by getting rid of the ATS kit!:roflmao::roflmao.

 

[Chevy1925]

I thought you already had an LLY turbo in it. I bet that will be enough to let you keep the rpm below 3000 which will probably keep the temps more reasonable.

you are probably right. the old trailer that was lighter never gave me this issue but i never turned over 3k rpm to hold speed. "built truck problems" :rofl:

What about adding an electric pusher fan for the trans cooler? Force the trans cooler to work.

I have had similar problems in AK, where I can get high trans temps at idle or in traffic but NEVER get the fan clutch to engage because of lower ambient air temps (that problem was solved by getting rid of the ATS kit!:roflmao::roflmao.

something i thought about as well but with e-fans, they will block air flow to the cooler when off. i could leave it on all the time but ill need to upgrade alternators at that point as id like to add a second oil cooler and fan. With the two i have now (1600 spal on the oil cooler and 1000 jegs on the fuel cooler), you can watch voltage drop on the gauge. its still enough to keep the battery charged and run everything without voltage issues but ill be getting to that point fast with anymore fans.



Im kinda going with the thermostat idea and then a different turbo with variable vane if that doesnt work out. ive wanted a 68 for a long time, this would be a good excuse to the wife :woott:

 

[Dozerboy]

260*+ trans temps ain't "warm temps" lol. They would continue but I kick it out of gear and use truck/trailer brakes from there

Oh I didn’t see that they were getting that high.
You don’t need to kick it out of gear and use the brakes the next he’ll will slow you down.


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[malibu795]

Never had that issue on 5+ mile long grades..
Fan off tstats closed would reduce cooling for trans
Spinning at those RPM Doesn't allow the fluid to sit in either cooler long enough to transfer enough heat.

I'd stick a fan, on a temp switch, on the external cooler.
Putting a lower tstat in would just make it take longer to happen

 

[Chevy1925]

Oh I didn’t see that they were getting that high.
You don’t need to kick it out of gear and use the brakes the next he’ll will slow you down.


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if only that were the case. this road is too damn winding or id be cruising 70 down it like i do everywhere else. i watched a new ford hualing ASS down another hill that isnt as bad as this one with a larger trailer. all i could think was "if a trailer tire goes with the speed hes running, that sucker is gunna be up side down in an instant".

there are two road that do this to the truck. the first road i figured was due to me being in 2nd gear and doing 40mph down it so no air across the cooler (the road is a 2 lane 7% grade that winds REALLY bad). This second one is the first time ive ever taken this load up/down it. its a really hellish trip on a loaded truck and trailer. tons of grades that vary and continue on a long up hill and vise versa coming down but a continual down grade. alot of MFG use that route to test trucks when loaded for temp issues and so on. seen GM out there, chrysler, and ford. My engineer buddy at chrysler has his test rig and other co-works test rigs delivered out to here to run these hills and test them. granted those are cars but still a good test on them.

Never had that issue on 5+ mile long grades..
Fan off tstats closed would reduce cooling for trans
Spinning at those RPM Doesn't allow the fluid to sit in either cooler long enough to transfer enough heat.

I'd stick a fan, on a temp switch, on the external cooler.
Putting a lower tstat in would just make it take longer to happen

yeah but if it gets me down the hills, im ok with that. they are the worse grades we have just due to how curvy they are. I dont think the pump is pushing fluid to fast either, its only going to see MAX 200psi from what mike told me. wouldnt think that would be too much if im turning 2800rpm under throttle and temps can still be under control but i dont know the fluid paths or how pressure changes with rpm and so on.

ive considered putting larger brakes on the trailer too. then i could use more brake as they suck as it is and ive adjusting them 3 times. they dont really make a bigger bolt on drum brake setup though. disc is cool but way more involved than i wanna get.

 

[malibu795]

Can swap to e-brake lippert 8k for ~600.00 plus shipping if you have eye/slipper
EoH convertion be about 1700.00 for 2 axle setup

 

[Chevy1925]

na, not a slipper setup. its a shackle setup. these are 7k 8 lug axles i have (pretty sure you have seen pics on FB).

 

[malibu795]

Yeah they don't make eye/eye 8k springs
550.00 axle for disc brake conversion...
650-700 for actuator
$150.00 in lines and and fittings
13" disc 8k for me make 7k versions uses 90s regal front bads

 

[THEFERMANATOR]

Mine does this, and I've talked to a few others with bone stock trucks that also had it happen. The problem is like you said, when the stats close, there is no coolant flowing around the radiator mounted cooler, and if your vehicle speed isn't fast enough to shed the heat, trans temps go wild. Theres one grade about 4 miles long coming out of the smokies that is 5-7% downhill, and if I drop below 45, trans temps shoot up 260+. Did it ladt time at 50, and held 245 trans temps, but the wife was NOT happy going that fast with a travel trailer in tow on a winding road.

The fix would be to route your heater core return line back to the radiator where GM returned it until the duramax came about. When mine was a 6.5l, trans temps were never an issue, but the heater core line returned right above it. I've seriously considered using the 1/2" line that goes to the degas bottle, and return my rear heater core line there, but that would render the degas bottle design useless. I also considered getting a mishimoto radiator and having a heater return line welded into it just to stop this problem.

 

[WolfLMM]

I'm just over here like man a 68r with turbo brake tuning would keep you from having to turn the rpm you do down hill.

I 2nd this!

 

[hondarider552]

James the automatic semi I have driven a few times at my work with an Allison has seen the same trans temp issues you have going down camp Verde hill at 80k.

 

[Chevy1925]

That’s not a bad idea ferm but I ain’t takin those radiator back out for a good while. I did that enough when I was getting everything in this past summer lol. I have a two piece upper rad hose right now and it’s on the pass side, I’ll try tapping into that with an adapter piece and see how that goes. Thanks for the idea!

Waid, you’re no help lmao

Well damn it brian, tell me the fix!