[usedBolt]

Interesting though that there is no maintenance interval for that fluid. There isn't even the word "transmission" mentioned anywhere in the manual.

For my 2017, there is a maintenance interval specified for the transmission fluid: 150K miles, no associated time. The dealer seems to think it has to be done every 5 years and is bugging me about it. Yes, the brake fluid and coolants are supposed to be changed every 5 years (or 150K miles). That's different.

In ICE vehicles, the transmission fluid gets full of contamination from the clutches in an automatic and gear wear in a stick. So changing it somewhere between 50-100K or around 5 years is fairly typical. The Prius also dirties the transmission fluid somehow - 90-100K is a common change interval, and what came out of my 07 at 75K was pretty beat up. But in a EV like a Bolt, there is practically no wear - constantly meshed reduction gears, that's it. So the fluid should last a long time. Though: does the Bolt use the gear oil for cooling the motor, like some other EVs? If so, I could see the possibility of heat damage (probably what's getting the Prius too). Still: my Bolt may be >5 years old, but has only 48.5K miles on it. Just not buying the idea that it needs the gear oil changed like coolant or brake fluid, both of which are much more exposed to air and hard use.

 

[GJETSON]

does the Bolt use the gear oil for cooling the motor, like some other EVs?

Yes. That is how they can pull 150 kW from a gallon can sized motor without cooking the magnets, and burning the winding varnish.

 

[Davit_Gegeshidze]

@Davit_Gegeshidze Are little hills >10° incline/decline?

less than 10 degrees for sure.

 

[GregBrew]

Could it be a spurious or intermittent error code being caused by a weak and/or failing 12V PbA AGM auxiliary battery?

 

[usedBolt]

Yes. That is how they can pull 150 kW from a gallon can sized motor without cooking the magnets, and burning the winding varnish.

So the dealer's right? Needs changing the fluid at 5 years despite the book not actually saying that? Most automatic transmissions these days are specced for 100K or more miles (or 10 or more years) between fluid changes, so it seems a bit odd for a simple reduction gear setup with circulation through the motor to need service on the order of what 20th-century stick shifts required (complete with occasionally grinding the gears). Has anybody here changed the oil at 5 years (regardless of mileage) and had it tested?

 

[TennErnieChevy]

There is a two stage, single speed, helical gear transmission.

Isn't this the same as a differential? Now, if it only had Posi-Trac.

 

[Shark]

A differential is a hypoid gear. I would change the fluid. The filter is more of a rock catcher. The way to keep the gears and bearings clean is by changing the fluid. Bolt is ball bearings. Most others are tapered bearings. Tesla also edit. Add ball bearings. Tesla has a proper filter in the oil stream. Bolt is more like a strainer.

 

[GJETSON]

Has anybody here changed the oil at 5 years (regardless of mileage) and had it tested?

Yes. This entire thread is well worth reading.

Transmission Fluid

Hi all, I just entered the 73k mile mark and can’t stop thinking about the transmission fluid. As far as I am concerned, there is no such thing as “lifetime” fluid and was wondering if anyone has changed their transmission fluid? Thank you in advance. Oh and btw, current gas prices in CA are $4...

www.chevybolt.org

 

[Davit_Gegeshidze]

less than 10 degrees for sure.

And it rolls

Could it be a spurious or intermittent error code being caused by a weak and/or failing 12V PbA AGM auxiliary battery?

I also thought about that and changed 12V Auxilary battery, but nothing changed

 

[Davit_Gegeshidze]

My problem is transmission, it's not about just changing the fluid. I'm trying to see, what can I do to fix that.

 

[mouldinguy1]

HI guys. My Bolt Euv says that it needs transmission Service and it rolls backwards even on a little uphills. My dealer in Tbilisi, Georgia told me to check transmission fluid. When I went to check level of the fluid, they said that the car doesn't have the transmission fluid at all. So can any of you guys know if transmission has any fluid or not, if it has how to check level of it and then if any of you has any idea what error code p1769 means for the transmission?
Thank you in advance.
P.S I live in Tbilisi, Georgia, so I don't have official dealer to fix it, so even a little information might be extremely useful for me.

My 2017 had the same problem turned out to be a result of not fully depressing the switch on the gear shift,it's very sensitive.

 

[Davit_Gegeshidze]

Quick update: As it turned out there's faulty Transmission range controller. That causes rolling everything, sometimes not working back up camera also is one of them. Problem is I can't buy this part in Georgia and now I'm trying to buy transmission range controller from US dealers and ship it to Tbilisi, Georgia.

 

[usedBolt]

Quick update: As it turned out there's faulty Transmission range controller. That causes rolling everything, sometimes not working back up camera also is one of them. Problem is I can't buy this part in Georgia and now I'm trying to buy transmission range controller from US dealers and ship it to Tbilisi, Georgia.

Anybody have the service manual? I think the range controller is an internal part in the transaxle, so it's probably not user-replaceable. It's a side effect of the use of ICEV parts as much as possible. Sometimes they fail.

Edit: also realized that Dr. Kelley of Weber State did a teardown of the transaxle (linked above, I think), so that's another source of info about the transmission range controller.

 

[Davit_Gegeshidze]

Anybody have the service manual? I think the range controller is an internal part in the transaxle, so it's probably not user-replaceable. It's a side effect of the use of ICEV parts as much as possible. Sometimes they fail.

Edit: also realized that Dr. Kelley of Weber State did a teardown of the transaxle (linked above, I think), so that's another source of info about the transmission range controller.

They said I should order it online and then change and program it here in Tbilisi, Georgia. So can anybody help me to find the part, if it's possible.
Thank you in advance

 

[GJETSON]

So can anybody help me to find the part, if it's possible.

I did that back in post #19. You are looking for the Transmission Range Selector Actuator/Transmission Range Control Module/TRCM

Module - GM (42687138)

 

[GJETSON]

I think the range controller is an internal part in the transaxle

Read my previous posts, and watch the Professor Kelly video.

 

[usedBolt]

Read my previous posts, and watch the Professor Kelly video.

Thanks. Went back to the Professor's vids. Yes, it's external, but it's apparently not a simple part. Might be a modified version of a standard a/t part, but from some years back and because of the Bolt's limited production could in fact be hard to get.

And yes, per the vids, the motor (stator at least) is cooled by the ATF in the reduction gearbox. So I'll (grudgingly, because the maintenance schedule doesn't really call for it and at <50K miles that truly is 90s if not older m/t oil timing, not even moderately recent a/t) let the dealer do it next time I have it in for something.

Interesting that the older Bolts have the transaxle in a coolant loop (the power electronics). The newer (22+) don't have that any more. Wonder why? Ineffective, or just cheaper to cut out some plumbing and hope for the best?

 

[GJETSON]

Interesting that the older Bolts have the transaxle in a coolant loop (the power electronics). The newer (22+) don't have that any more.

Not just the transaxle. More importantly, that ATF also cooled the motor. It will now run hotter, since it is no longer going through that missing heat exchanger. There is only one reason to remove it...to save money.

 

[LoneR]

... and telematics/dealer-logs may have shown the temperatures were within acceptable ranges without it.

 

[GJETSON]

... and telematics/dealer-logs may have shown the temperatures were within acceptable ranges without it.

I can see Tesla getting this data. I doubt the Bolt computers are saving, and uploading that amount of data. Dealers pulling data and sending it to GM is a dream.