Transmission running too cold?

[ksa8907]

Originally Posted by Tahoe_Hybrid

the most stress is on the front Sun gear and input/out shaft there is a risk every time it 'starts' the it will blow apart


someone seized an engine and ended up blowing apart the transmission along with it.. i asked them why they did not have it towed , they did not say anything


it does have two 60kw electrical motors that need to be cooled to make up for it


it also comes with the heavy duty tow package ( for the cooling only since the max is 6200 pounds for 2wd )

Speaking of towing, we pulled a uhaul 4x8 with about 800 lbs in it, cabin filled to the bursting point, along with two bicycles mounted on the roof at up to 85mph cruising and the trans never went over 171°F. So yes, the cooling is quite good!

[Tahoe_Hybrid]

Originally Posted by ksa8907

Speaking of towing, we pulled a uhaul 4x8 with about 800 lbs in it, cabin filled to the bursting point, along with two bicycles mounted on the roof at up to 85mph cruising and the trans never went over 171°F. So yes, the cooling is quite good!

yeah make sure Not to use the Revise gear when towing (just don't put yourself in that situation )

you will damage the CVT revise gear also use the M gear m3 if you want AFM M4 give you full power V8 with E-Assist (besure to turn on the A/C so you don't accidentally deep CYCLE the high voltage battery i.e getting the State of charge too high) it will be worth the slight extra gas
as that HV battery is expensive.... so also good to use the A/C in the winter occasionally for 5min or so (this will keep the seals in good condition for many many years )


if you can afford it get 91/93 octane for the MAX amount of MPG and MAX low end power i get about 27mpg on the highway with it worth the extra 30 cents as 87 octane would cost me over 5$ to go 27 miles
i save 1.34 per gallon with the high octane fuel chevron or mobil are the best as they don't screw you on the octane you buy Shell/arco have screwed me on the octane when I paid for 91 octane they gave me 87 octane it happened at 3 stations for both arco and shell. what a scam they are pulling

[ksa8907]

Originally Posted by Tahoe_Hybrid

yeah make sure Not to use the Revise gear when towing (just don't put yourself in that situation )

you will damage the CVT revise gear also use the M gear m3 if you want AFM M4 give you full power V8 with E-Assist (besure to turn on the A/C so you don't accidentally deep CYCLE the high voltage battery i.e getting the State of charge too high) it will be worth the slight extra gas
as that HV battery is expensive.... so also good to use the A/C in the winter occasionally for 5min or so (this will keep the seals in good condition for many many years )


if you can afford it get 91/93 octane for the MAX amount of MPG and MAX low end power i get about 27mpg on the highway with it worth the extra 30 cents as 87 octane would cost me over 5$ to go 27 miles
i save 1.34 per gallon with the high octane fuel chevron or mobil are the best as they don't screw you on the octane you buy Shell/arco have screwed me on the octane when I paid for 91 octane they gave me 87 octane it happened at 3 stations for both arco and shell. what a scam they are pulling

I left it in drive and only put it in m4 when we were coming down the mountains. And yes, using premium fuel kept it from downshifting as much, spent a lot of time in a lower gear ratio, hard to tell which one with this trans.

Revise gear?

Sorry for the thread jack!

[Tahoe_Hybrid]

Originally Posted by ksa8907

I left it in drive and only put it in m4 when we were coming down the mountains. And yes, using premium fuel kept it from downshifting as much, spent a lot of time in a lower gear ratio, hard to tell which one with this trans.

Revise gear?

Sorry for the thread jack!

reverse gear my bad it's bad to back up with a load on the cvt gear

dont' use drive gear when towing unless your above 45mph, so you can stay out of 6th gear [EVT2], then you can switch from M4 to Drive, you can cause severe damage to the CVT portion if you tow in CVT mode but it's your transmission

it's easy to tell
0-15MPH 1st
0-29 mph 5th gear[EVT1] [Auto Stop]
15-35 2nd
35-50 3rd gear
40-45mph 6th gear[EVT2 v4-DFCO 50MPH and below, Fuel economy mode]
55mph > 4th Gear [50-55 varies between 3rd and 4th gear depending on engine load]

as you can see the gearing is complicated



4th gear is good tell 90mph it will be about 2300 rpm at that speed


it's hard to tell but i go by the RPM (shifts are smooth a silk and physically undetectable)

[EcoCivic]

Originally Posted by Tahoe_Hybrid

reverse gear my bad it's bad to back up with a load on the cvt gear

I think you are confusing a CVT with a DCT. Most CVT transmissions use a torque converter (a fluid coupling) like a regular auto instead of a clutch, so they aren't harmed by crawling forwards or backwards. However, some CVTs like the ones found in some Hondas use a start clutch instead of a torque converter, so it's best to avoid crawling in those just like with a DCT.

A DCT (Dual clutch transmission) has no torque converter. Instead, it has clutches that may overheat from slipping and fail if you crawl for a long time, especially under load. The reason for this is because it can't fully engage the clutches until you reach a certain speed or the engine would stall (like letting the clutch out at too low of a speed in a manual transmission). Therefore, the clutches must slip. This quickly makes a lot of heat, which can destroy the clutches if done repetitively or for extended periods of time, especially under load.

[Tahoe_Hybrid]

Originally Posted by EcoCivic

I think you are confusing a CVT with a DCT. Most CVT transmissions use a torque converter (a fluid coupling) like a regular auto instead of a clutch, so they aren't harmed by crawling forwards or backwards. However, some CVTs like the ones found in some Hondas use a start clutch instead of a torque converter, so it's best to avoid crawling in those just like with a DCT.

A DCT (Dual clutch transmission) has no torque converter. Instead, it has clutches that may overheat from slipping and fail if you crawl for a long time, especially under load. The reason for this is because it can't fully engage the clutches until you reach a certain speed or the engine would stall (like letting the clutch out at too low of a speed in a manual transmission). Therefore, the clutches must slip. This quickly makes a lot of heat, which can destroy the clutches if done repetitively or for extended periods of time, especially under load.

Gm says it's a CVT or as they call it a EVT

Continuous Electric Ratio Hybrid Transmission With 4 Fixed Gears.


Gear Ratios
1st — 3.69:1
2nd — 1.70:1
3rd — 1.00:1
4th — 0.73:1
EVT #1 — Infinity to 1.70:1
EVT #2 — 1.70 to 0.50:1
Reverse — Infinity to 1.70:1

[EcoCivic]

Originally Posted by Tahoe_Hybrid

Gm says it's a CVT or as they call it a EVT

Continuous Electric Ratio Hybrid Transmission With 4 Fixed Gears.


Gear Ratios
1st — 3.69:1
2nd — 1.70:1
3rd — 1.00:1
4th — 0.73:1
EVT #1 — Infinity to 1.70:1
EVT #2 — 1.70 to 0.50:1
Reverse — Infinity to 1.70:1

Here's an interesting idea- a CVT that the driver can set what the fixed ratios are and paddle shift it. That would be pretty fun in my opinion

[Tahoe_Hybrid]

Originally Posted by EcoCivic

Here's an interesting idea- a CVT that the driver can set what the fixed ratios are and paddle shift it. That would be pretty fun in my opinion

you know how Toyota claimed they had a "first" CVT with a first gear launch
https://www.fuelsandlubes.com/toyota...t-launch-gear/



well GM beat them too it with a 4 SPEED launch back in 2008...

i think toyota still grappling with the pickle matrix. and did not notice a CVT with a 4 speed transmission was all ready on the market..

basically they reinvented the two mode

[hayden55]

I wonder how bad it is to tow with the cvt in the Prius. I pull a 1000lb boat from 90k to 160k now lol.

I'd probably add that the GM/BMW/Chrysler hybrid system is quite different. They have 6 different operating modes where the Toyota just starts in first then swaps to the CVT to shift the efficiency band up to the range where most of us do all of our driving. The trios group engineering effort was to create more torque with a smaller electric drive system for SUVs as the main goal.

[gumby79]

With my 6sp(7 counting TC lockup) Allison, 145°f to enter learning mode. Per the Trans Builder keep it above 145°f to keep it alive and adjusting the shift trims for current conditions.

Dodge put out a TSB about transmission fluid viscosity issues. At -10 F the ATF+4 trans fluid congeals/ freezes in the air to liquid cooler mounted in the cooling stack, restricting flow through the cooler circuit causing the transmission to overheat.
I have not gotten a straight answer at what temp this is a problem with Allison fluid. Dodges fix was to bypass the air unit and just use the massave remote liquid the liquid unit bolted to the side of the block using a heater core circuit. And tell the customer to swap back and forth for towing in hot and solo in cold.

Final advice I implemented routing.
Stock is:
Trans/water/air/trans

Recommended:
Trans/air/water/trans

Reasons:
Industrial Allison standalone computer locks the TC@ 20mph ~1/2 way through 2nd. So no TC heat, it will(my Allison) run too cold and seldom be in learning mode especially in MT winter. So far single digits trans temp 161° F/ CT,171. Without pulling heat from the Cummins the Allison would not be happy. And the worst of winter is yet to come.

Find out what temp your TCM enables learning. That is the magic low temp, bottom line.
If it is all hydraulic mechanical so long as it's not overheated it doesn't care . However the TCM from the 46RH that came out did disable the electrohydraulic OD (.61/2.44 final) till the trans hit 45°f ~1.5 mi @ -20F when pluged in CT ~60°F

---
+1 on the user selectable raito and #of shifts available CVT shift patterns. I still dont get the point of a CVT with set shift raitos , especially it described here to match a normal automatic . Only thing I can come up with is too many complaints about people feeling like they're driving a snowmobile with three RPMs accelerating, cruising, and compression braking.