174k, Transmission lost 2nd gear engine braking and 6th gear

[linuxgod]

Figured I’d start a new thread on this for posterity, rather than cluttering up my Towing or my Build thread…

We were at Cruisers on the Rockies last week, finishing up Poughkeepsie and the wall when I noticed while descending hurricane Pass that my engine was idling at ~1200 RPMs when going downhill in second gear. I should have more engine braking than that, right? @kcjaz and @Oakleyguy behind me said they could smell my brakes, so I went into first and crawled down the rest of the trail.

Once we hit Cr110 (the gravel county road into Silverton), getting back to camp I could tell something wasn’t right. Checked fluid level and it seemed ok, fluid that came out was a mix of red and brown but seemed fine for having 25k on it. Nothing shiny came out but we didn’t drop the pan.

Went back out with @kcjaz that evening onto a downhill section of road, out the truck in 4Lo. 1st gear creeps at 4-5mph and revs up, 2nd gear idles at 1200 rpm with an occasional bounce down to 700 before jumping back up, but the truck went 5, 10, 15, 20, 25 mph still at idle before I put it in 3rd and it jerked us forward as the engine revved to 5k rpm’s. 4th also engaged ok.

Got back to camp and was frantically trying to figure out a plan. Nobody knew of a good transmission shop in the area. I’d heard poor reviews of the Toyota dealer in Montrose. Ben at Slee made some calls and said Durango had a good tech but they were backed up. Christo and Ben looked at trying to load me into Christo’s toy hauler to get it to Slee but with the lockouts on my sliders I was too wide to fit with the slide in on the toy hauler.

Oh and I’ve neglected to mention this was towards the end of our road trip where I’d done about 4k miles towing our trailer out to Crater Lake, OR, Redwoods and Lassen Volcanic in CA, and Great Basin NP in NV. So even if I could drop the truck in Durango, I had to figure out a plan for the trailer as it couldn’t stay at Kendall Mountain long term.

Lots of running around for the next 24 hours trying to hatch a plan. Ultimately:

• @kcjaz gave me a lift to Durango to rent a car so my father and sons could get to Denver airport and fly home. This was to reduce complexity if I was stuck.
• @nakman agreed to haul my trailer back to Denver
• Chris Barrington was kind enough to let me stash the trailer behind his garage until I can get the truck repaired.
• @nakman, @Oakleyguy, @Romer, and Tim’s daughter caravaned to Denver with me driving the 200. I did my best to avoid 2nd gear. 6th slips and Reva about 500rpm higher than 2nd so I didn’t use it at all. 4th worked but the lockup would disengage if I wasn’t at least moderately on the throttle so I mostly stuck to 5th and 3rd. Thankfully the tranny didn’t grenade on me and I made it to Slee

A bunch of additional thanks to the following folks. @laserturbo91 for running someone up Stony Pass on Friday morning so Tim could pull my trailer. @Romer for offering his driveway to store my trailer. @Oakleyguy for loaning me his 700 so I could go talk to the Silverton RV parks about storage, and probably a few others I’m forgetting.

Also, a huge thanks to Slee for trying to find a way to haul my truck back to their shop, but also for being willing to take on the repair. And a tremendous thanks to @nakman of Gamiviti for pulling my trailer 350 miles to Denver. If you haven’t met Tim even before this I would have told you he’s the absolute nicest and most helpful guy I know. (Also he makes some kick ass gear).

My truck is at Slee right now, and on their schedule for 8/18 to get it on a lift and examined. Hopefully something opens up sooner but if not I’ll be back in Denver late Sept anyway and will pick it up then. Ben seemed to think it’ll likely need a reman transmission, but I’ll keep my fingers crossed that it’s “only” the valve body which anaboht half the cost.

 

[KLF]

Bummer. Best of luck with the repair, looks like you're in good hands.

 

[Romer]

Geoff,
Glad you made it home OK and everything is on track to be fixed. Here is a view of you following your trailer with Tim towing it leaving Silverton. Really glad you were able to drive your truck from Silverton to Golden. Enjoyed our radio banter on the way home. I learned a lot about transmissions.

It will be interesting to hear what the actual problem is

 

[kcjaz]

@linuxgod, glad you got it sorted. It’s really cool to see how the community responds when someone has an issue. Several examples last week at COTR. Your situation, the 200 with the busted UCA, and the 100 with the broken tie rod and drive shaft, and the 7H flat tire. And these are just the situations I am aware of, I am sure there are others. Parts and help just coming out of the air.

 

[tbisaacs]

the community rallies once again. Best of luck Geoff!

 

[nakman]

glad I was in a position to help Geoff, and that you're home and your trailer has a safe place to hang out for a while. Chris is @Txanm.

also thanks for taking the time to hook me up with the awesome OBD Fusion dashboard, which provided hours of entertainment on our journey back.. and reminded me why I don't like pulling big trailers, lol. I'm sure we'll see you again soon, just shout if you need anything else in the interim. -tim

 

[onelittlestar]

First, nice to meet you guys at COTR, I was so sleep deprived the day we were out I fell asleep at least twice on the trail…and thank you for helping me get back into 4Lo quickly

Second, damn, that really sucks about the trans. Did you get up the wall? What day were you out on Poughkeeepsie? We were up Thursday, but I don’t recall seeing yall.

 

[Oakleyguy]

First, nice to meet you guys at COTR, I was so sleep deprived the day we were out I fell asleep at least twice on the trail…and thank you for helping me get back into 4Lo quickly

Second, damn, that really sucks about the trans. Did you get up the wall? What day were you out on Poughkeeepsie? We were up Thursday, but I don’t recall seeing yall.

Poughkeepsie was Wednesday for @linuxgod.

 

[linuxgod]

Everyone was hugely helpful. It speaks volumes to the kinds of folks who are part of the Land Cruiser community.

A friend of mine here at home offered to loan me their extra vehicle until my truck is back while his son is racing formula cars in the UK. 6 speed Jetta to wagon… if only it was brown Returning the favor with a shameless plug for him (Jason Pribyl Autosports - https://jasonpribylautosports.com/)

 

[linuxgod]

First, nice to meet you guys at COTR, I was so sleep deprived the day we were out I fell asleep at least twice on the trail…and thank you for helping me get back into 4Lo quickly

Second, damn, that really sucks about the trans. Did you get up the wall? What day were you out on Poughkeeepsie? We were up Thursday, but I don’t recall seeing yall.

I did make it up the wall. Ended up leading part of the group up and out since there were 11 trucks and that was too many cooks to fix a tie rod.

If it turns out to be a bad valve body I’m going to blame the last obstacle exiting Poughkeepsie as the culprit, though my transmission and skids are both contact free. If it’s a bad b2 brake in the transmission I blame towing

 

[linuxgod]

glad I was in a position to help Geoff, and that you're home and your trailer has a safe place to hang out for a while. Chris is @Txanm.

also thanks for taking the time to hook me up with the awesome OBD Fusion dashboard, which provided hours of entertainment on our journey back.. and reminded me why I don't like pulling big trailers, lol. I'm sure we'll see you again soon, just shout if you need anything else in the interim. -tim

Thank you!

Happy to have been able to help with OBD Fusion. It’s almost too entertaining to have visible, I know. (That and a tank of gas and a burger was the least I could do!)

Hopefully we get to catch up before next summer. If you decide you want to fly into Knoxville or Indianapolis for COTR 5 and ride with me you’re welcome to!

 

[linuxgod]

It will be interesting to hear what the actual problem is

That transmission was super sketchy a few times but I’m glad it held up.

I don’t know that Slee will actually rebuild my transmission vs just ordering a reman one. So if the issue isn’t obvious when they inspect it we may never know, though if they tell me they opened the pan and there’s metal in it or the valve body tested ok based on the FSM it seems like the B2 brake is probably the cause as it’s the one common failure point between both gears and symptoms those gears experienced

Sadly to replace that part you have to dismantle the entire transmission, so at that point might as well replace all the clutches and brakes…

 

[TeCKis300]

Sorry for the troubles out on a big trip no less. At the same time, it's encouraging to see the community band together. I find these unplanned "adventures" to be what makes them memorable. An opportunity to build deeper bonds within the crew. I mean, why else would a bunch of guys go out to the middle of nowhere and encourage shenanigans. I enjoy the roll with it attitude and as a team, we always find a way out.

I think you nailed it with the B2 Brake issue above.

As I also wheel hard and tow at the upper end, I'm wondering how to ensure long component life and avoid failure. I'm right about the same mileage too.

Towing is towing and the only things I've done is to add a transmission aux aux cooler, while also servicing fluids on a regular interval.

I'm curious how often you're using 4lo?

I religiously use it once I hit dirt as it greatly reduces torque loads within the transmission. Only time I'm not in 4lo is when I'm on a fast 30mph+ fire road or desert wash.

Also use it religiously when towing, literally as soon as I hit the entrance gate in a campground, even if it's completely flat.

 

[TeCKis300]

So what does the B2 Brake look like? If that's the root issue, it's a clutch pack and the friction material is worn either from loads, heat, or both. Unfortunately looks like a rebuild or replace rather than something that can be serviced.

Awesome great build video here. @6:45 and watch through @10:30.

 

[Artie]

So what does the B2 Brake look like? If that's the root issue, it's a clutch pack and the friction material is worn either from loads, heat, or both. Unfortunately looks like a rebuild or replace rather than something that can be serviced.

Awesome great build video here. @6:45 and watch through @10:30.

Cool video. Tranny internals are always both fascinating and confusing to me.

He mentions “revised parts” on this assembly, I’m curious how this works vs OEM. I would imagine some improvements are possible when looking at Cruiser builds (weight and tire sizes) and use cases vs OEM but I’m also guessing any changes comes at a cost somewhere.

 

[linuxgod]

Sorry for the troubles out on a big trip no less. At the same time, it's encouraging to see the community band together. I find these unplanned "adventures" to be what makes them memorable. An opportunity to build deeper bonds within the crew. I mean, why else would a bunch of guys go out to the middle of nowhere and encourage shenanigans. I enjoy the roll with it attitude and as a team, we always find a way out.

I think you nailed it with the B2 Brake issue above.

As I also wheel hard and tow at the upper end, I'm wondering how to ensure long component life and avoid failure. I'm right about the same mileage too.

Towing is towing and the only things I've done is to add a transmission aux aux cooler, while also servicing fluids on a regular interval.

I'm curious how often you're using 4lo?

I religiously use it once I hit dirt as it greatly reduces torque loads within the transmission. Only time I'm not in 4lo is when I'm on a fast 30mph+ fire road or desert wash.

Also use it religiously when towing, literally as soon as I hit the entrance gate in a campground, even if it's completely flat.

I only use 4Lo on trails. I generally stay in 4Lo on trails and often use 2nd gear instead of first.

It’s interesting to me that the failure is on the 2nd gear brake. I would have assumed a clutch pack would have gone out first. Most of the heat seems to be generated during acceleration when the torque converter is unlocked, and I would have thought that’s also where the majority of the driveline stress happens. I guess 2nd gear engine braking and 6th gear engagement are the same brake so maybe it’s just a lot of 6th gear wear, but I don’t tow in 6th and the truck gets very little highway usage without towing compared to most vehicles.

I do rely on downshifting a lot in the mountains and taking route 50 through Nevada there are a lot of moderate passes. I also tend to push the truck hard rather than backing off and taking it easy.

The concerning part to me is there really wasn’t any warning. It was fine and then it wasn’t. There wasn’t slipping or other symptoms which would indicate pending doom. About the only warning I’ve possibly had was that downshifts into 2nd gear or occasionally when being in 2nd around town and going from gas to brake I would sometimes get a metallic clunk. I was assuming this was a worn u-joint or 2-piece driveshaft with some play in it binding up or releasing, but now I’m wondering if it was the B2 brake not engaging correctly sometimes. It’s been doing that for a year at least though.

Given the lack of warning I’m still holding out a little hope that it turns out to be a cracked valve body or something else which is an unexpected failure mode and Toyota didn’t capture in the FSM.

 

[bloc]

The B2 brake is a clutch pack, but instead of controlling one spinning element compared to another, it controls engagement of a spinning element to the transmission case.

This guy does great "power flow" demonstrations of most automatic transmissions and I've used his videos as reference material for diagnostics on a number of them over the years. Should be a good way to visually understand what's going on.



I had to rebuild the GM 6L80 that I put into my 80-series after third gear started to slip on a trail in Utah. Knowing each clutch controls multiple gears I had to use a laptop running HPTuners to manually shift avoiding 3rd in an attempt to keep the relevant clutch healthy enough to get it home, since it was also part of 5th or 6th gear. I forget which clutch was burned up but that was the issue. It was shockingly easy to do the whole rebuild in my garage.. modern transmissions with the processing power to adaptively "learn" the clutch fluid volumes means precisely shimming the packs isn't necessary like it used to be.

Not that any of that helps in your situation.. sorry you're dealing with this. It would be interesting to get a real diagnosis if possible. Clearly this stuff doesn't happen often in the AB60E or F.

 

[TeCKis300]

I only use 4Lo on trails. I generally stay in 4Lo on trails and often use 2nd gear instead of first.

It’s interesting to me that the failure is on the 2nd gear brake. I would have assumed a clutch pack would have gone out first. Most of the heat seems to be generated during acceleration when the torque converter is unlocked, and I would have thought that’s also where the majority of the driveline stress happens. I guess 2nd gear engine braking and 6th gear engagement are the same brake so maybe it’s just a lot of 6th gear wear, but I don’t tow in 6th and the truck gets very little highway usage without towing compared to most vehicles.

I do rely on downshifting a lot in the mountains and taking route 50 through Nevada there are a lot of moderate passes. I also tend to push the truck hard rather than backing off and taking it easy.

The concerning part to me is there really wasn’t any warning. It was fine and then it wasn’t. There wasn’t slipping or other symptoms which would indicate pending doom. About the only warning I’ve possibly had was that downshifts into 2nd gear or occasionally when being in 2nd around town and going from gas to brake I would sometimes get a metallic clunk. I was assuming this was a worn u-joint or 2-piece driveshaft with some play in it binding up or releasing, but now I’m wondering if it was the B2 brake not engaging correctly sometimes. It’s been doing that for a year at least though.

Given the lack of warning I’m still holding out a little hope that it turns out to be a cracked valve body or something else which is an unexpected failure mode and Toyota didn’t capture in the FSM.

I use my truck in the same way, also using a lot of 2nd gear engine braking in the mountains when towing and off-road. I'm likewise interested and concerned about how I use the vehicle, but also how I can better operate the vehicle to avoid a similar situation. Time may tell?

One thing I notice is that engine braking also causes the transmission temps to jump. More in the torque converter, but it's obviously also loading up the transmission and clutches as it shifts with large loads and often at really high RPM to get enough engine braking. You know things are heavy when the engine is screaming near redline in second gear, for miles at a time, and still may need to reach for the caliper brakes. Though using more caliper brakes is not really a safe option as braking needs to be sustainably in a manner that doesn't fade and overheat the them with miles more downgrade ahead.

About the only thing outside of driving tricks to further preserve the transmission is re-gear, add more aux tranny cooling, and change tranny fluid often.

I did tow for a brief time on 33s on stock gearing and that was surely harder on the transmission when taking off from a stop, which was one of the main drivers to regear earlier. I'm wondering how long you might have towed on 33s/34s before re-gear as that may have affect clutch pack life? 8-speed guys have great low end gearing so hopefully not as much a factor there with big tires.

Let us know what you find and hopefully there's a simpler/cheaper solution than what we're postulating.

 

[linuxgod]

I use my truck in the same way, also using a lot of 2nd gear engine braking in the mountains when towing and off-road. I'm likewise interested and concerned about how I use the vehicle, but also how I can better operate the vehicle to avoid a similar situation. Time may tell?

One thing I notice is that engine braking also causes the transmission temps to jump. More in the torque converter, but it's obviously also loading up the transmission and clutches as it shifts with large loads and often at really high RPM to get enough engine braking. You know things are heavy when the engine is screaming near redline in second gear, for miles at a time, and still may need to reach for the caliper brakes. Though using more caliper brakes is not really a safe option as braking needs to be sustainably in a manner that doesn't fade and overheat the them with miles more downgrade ahead.

About the only thing outside of driving tricks to further preserve the transmission is re-gear, add more aux tranny cooling, and change tranny fluid often.

I did tow for a brief time on 33s on stock gearing and that was surely harder on the transmission when taking off from a stop, which was one of the main drivers to regear earlier. I'm wondering how long you might have towed on 33s/34s before re-gear as that may have affect clutch pack life? 8-speed guys have great low end gearing so hopefully not as much a factor there with big tires.

Let us know what you find and hopefully there's a simpler/cheaper solution than what we're postulating.

I suspect if it’s a clutch or brake we’ll never know because it’ll be cheaper and faster for Slee to order a reman and swap it than to break mine down and R&R the whole thing. Which is too bad because I’m sure there’s a lot to be learned. And I suppose if someone really wants to know they can have mine to break down for the cost of the core charge and shipping.

I bought the truck with 49k miles and drove it one summer trip to Yellowstone with a trailer that was about 1000# lighter. No mods except a roof rack. I went right from stock tires to 34s the next year at about 65k miles. Drove that way until I did my regear around 110k spring of 2021. I’ve done 64k miles since then, and went to 35s just under 2 years ago at 147k. I’m at 174k now. (Started pulling the heavier trailer in 2018 so I had maybe 80k on the truck at that point).

My gut says gears and tires had less to do with the issue than the sheer weight of the trailer and the fact that I’ve probably pulled it 50k miles. We had a little debate on the radio if full transmission fluid exchanges were actually a bad thing but I doubt it

Side note: even when I downshift, if I need to brake I always “overbrake” and slow down more than is necessary, then go back to letting engine braking do its thing, rather than riding the brakes.

 

[linuxgod]

Update:

The following codes were found. P0729 Gear 6 Incorrect Ratio, and P2714 Pressure control Solenoid “D” Performance or stuck off.

Slee got the truck in and pulled a sample of the transmission fluid. They said there were metal specks in the fluid and were recommending a replacement transmission.

P0729 doesn’t shock me as 6th gear seemed to be higher RPM than 5th gear. I didn’t think to check if it was revving the same as 4th but it showed 6th in OBD Fusion and revved about 500 RPM higher.

P2714 seems to be a pretty generic “detected pressure wasn’t right” code as best as I can tell on a few forum searches.

I’ll trust Slee that there is material in the fluid and swapping the transmission makes the most sense. My gut says “try a new valve body” but that’s easily a $1500 gamble, and neither of the codes directly map to my lack of 2nd gear engine braking.