The 5.29 Mega Thread!!

I have 5.29's with 33's and experienced the speed cutoff around that speed. I normally don't drive that fast but I do have to make passes on single lane mtn roads often and that's when I experienced it the first time. That alone was worth getting it fixed. Luckily there wasn't an oncoming car but it could have been ugly.

I do have VF tuner though so I modified the stock tune so there isn't a speed limit anymore. I also changed the settings to 5.29 gears and 33in tires and the shift points did improve. Not to mention I increased throttle input for each gear so I can keep the pedal in the same spot and keep accelerating as the truck upshifts and not have to keep pushing the pedal down to keep accelerating instead of just bogging down. I personally loved this modified stock tune, but recently went to the Blackhawk tune.

This tune drives very well and has a more linear power band with increased torque, especially in the mid range, but it's important to point out it does hold gears longer than the stock tune and will hold a gear until you reach a specific speed with light throttle. For instance, when I'm in town driving trying to drive slow and get good mpg's, the truck will hold 4th and won't shift to 5th gear until 36mph. 6th gear won't happen until you hit 47mph. Where as the stock tune would go into 6th whenever there was minimal load, maintaining speed at 35mph even. Stock tune did get better in town mpg, but the Blackhawk tune does get better mpg on the highway and holds 5th and 6th gear better at highway speed. I've found my tank averages are basically the same with these differences. I've only run 4 tanks on the tune so it's hard to say for sure.

If you're happy with the stock tune, maybe reach out to a tuner and see if they will adjust the gear ratio, tire size, and speed cutoff at the minimum. Maybe this will be a cheap option![/QUOTE]

 

You have me curious about the stock tune throttle input you adjusted. How does that work when you're at highway speeds and no longer need to accelerate?

I'm also intrigued by that blackhawk tune and needing to reach specific speeds to shift... even though 5.29s drastically improved drivability I still get frustrated when it decides to shift to 6th when I'm doing 35 through town.

 

It took me about 4 tries to get it right. I took the stock tune throttle inputs and then increased by say 5-10% for each gear. I've pasted a snippet below of some old values. I have it so a normal steady increase would need say 20% push into the pedal and hold it. Once you get to the speed you want, I could lift up to say 10% and maintain speed. It worked flawlessly at highway speed since you didn't need have your foot halfway into the pedal to maintain speed since it's increased about 35% more pedal input (6th gear vs 1st) at the same position as you'd have the pedal in 1st gear since each gear increased. When going up a steep hill at 65 and the truck downshifts to 4th, instead of it accelerating (with same pedal position) up to 75mph, it would literally hold 65 since 4th gear had less throttle input. Also the percentage of throttle between 4th and 5th was the most since that's the biggest jump in RPM for all gears. Now with the blackhawk tune when my truck downshifts to 4th up a hill at 65mph it does speed up and I have to lift off the pedal to maintain speed. Then it downshifts to 5th and I have to give it more throttle (That's the only time it's really annoying though, it seems to have increased throttle or it just holds higher rpms for in town type driving where I can keep my foot in the same spot as it upshifts and accelerates).

One thing to note about how you get annoyed with in in 6th at 35mph, with increased throttle, it actually wasn't noticeable compared to stock tune where you just don't have enough throttle and have to give it more gas to try and maintain that speed. Also, it holds gears slightly longer since each gear has more throttle. Anyway, the tune makes for a great driving experience not going into 5th gear until 36 mph the majority of the time. It's always behind some prius doing 33mph in a 40mph speed limit area and you're sitting around 2000 rpm with the mpg bar at 15-22mpg vs 25-30mpg or so if it would go to 5th. (I have a gear lock tune so I can technically mitigate this by forcing it into 5th, but that gets annoying and I have an auto for a reason. I drove a manual 2000 tacoma for 11 years).

It sounds like you should give the tune a try if you don't have access to modifying the stock tune. Overall the tune is more enjoyable to drive compared to my modified stock tune.

 

How'd your throttle changes affect cruise? Did it help it not be so aggressive trying to maintain speed? (actually, I don't think we can change cruise values, I recall seeing something from OTT stating throttle and shift schedules are different when using cruise and can't be accessed?)

I do have VFTuner, and currently on the OTT 5.29 tune. Overall I like the tune, but there are things I would like to try and improve on and the guys at OTT are only willing to do so much, so I've been thinking of trying some different tunes out there to see if I like anything more.

 

Dang, I've wanted to try OTT but the cost of it compared to my cheap upgrade fee from KDMAX to Blackhawk is why I went that route.
So OTT tune will go to 6th at low speeds like 35 mph? What improvements did you notice over stock? They have a thread where they dyno'd all the tunes and it shows OTT making the most torque. But it's comparing against the old blackhawk tune. Also they did 3 runs on the dyno for all tunes and took the best. The stock tune actually put out the most torque at low RPM's (like 2000rpm on a throw-away run they did because that run had less HP up top than the one they used to compare all the tunes). Also about a year ago they promised on a forum to give users the tune to try for free like KDMAX would do and then pay if you actually like it and by the time I got around to asking for it a couple months later they no longer honored that so I got a bad taste in my mouth from that experience.

I didn't do anything to cruise control and every tune I've tried doesn't really make CC really any better than stock from what I can tell. I've done several iterations of the KDMAX tunes. Those tunes drive well too but I noticed a loss in torque. It's more linear power than stock but relies on heavy amounts of added throttle for the FEEL of more torque, but then you realize over time it's all throttle. When you go to give it more throttle it was just dead and was lazy to downshift as it wanted to hold that gear instead of a quick downshift into the power band if you were at a lower RPM. But it did drive really well on highway. Customer service was all time and Kreg is the man. He is the only tuner that was responsive and would do custom edits for anyone and have it back in an hour!

Blackhawk is a fairly similar feeling tune to KDMAX but with actual torque gains and more natural/predictable throttle inputs. KDMAX did have some really good upper end power from 4k rpm to redline. But you're rarely at those RPMs and Blackhawk puts the power where you need it most of the time.

Anyway since you have VFTuner, I can send you my stock tune and see what you think. I'd love to hear your opinion on it against your current OTT tune.

 

The CC shift values can be adjusted through VF Tuner. Your tuner may not know that because they can’t actually open the maps, only flash what they’ve been given from OTT. You can request that the CC shift values be adjusted, and they may be able to get that for you. If you have the availability to look at the maps, CC shift control is under VFT EROM close to the bottom of the map selections. You can do you homework and find out where you want the CC to shift at.

 

I don't think the ECM is programmed with gear ratio and tire size, those sound more like inputs to the tuning program. It runs some algorithms against those to adjust certain other parameters in the ECM. That is what I would really like to understand - what parameters are actually adjusted, and what inputs from the vehicle sensors are used against those parameters to decide when to shift. Unless a tuner can explain all of that to me, I have no desire to apply a tune, especially when I am happy with the way it drives.

If the ECM is limiting speed to 83 mph, it must be using the RPM to calculate what the actual speed is. By my calculations, it thinks the vehicle is going around 100-105 mph. According to the Google, the Tacoma has a top speed of 113 mph, so maybe my calculations are a little off.

 

Yes, the automatic trans trucks calculate off of a speed sensor in the transmission that measures driveshaft speed. That is what it uses to limit top speed. To fix it in a tune, they simply change the maximum allowable speed a higher one, like setting it to 150 mph or similar. Something unrealistic that covers the bases with extra overhead built in for the deeper gearing.

The manual transmissions don’t have this limitation, they simply govern off of the vehicle speed from the ABS system, which isn’t affected by a regear. I have not driven my truck to top speed to see what that speed actually is.

If you don’t care about being limited on top speed, then you don’t need to do anything. If you wanted to do something about it, you could get a stock edited tune flashed with a raised max speed. That would maintain current driving behavior without implementing any sort of aftermarket tuning characteristics, if you’re happy with how things are but want to boost the top speed back to normal.

What I don’t know is what aftermarket tunes specific for gear ratios do. For example, I don’t know what the difference is between OTT’s 3.91 or 5.29 tune is, besides the speed limit fix. I’m assuming with the 5.29 tune they further tweak shift points so that you aren’t shifting proportionally earlier, but I don’t really know and I have very little experience with the automatic trucks, so it’s hard to say.

 

What gear oil is everyone using? I was thinking synthetic and I'm in Florida. I have been using Lucas 85/140 but wanted to extend the service interval a bit. Thanks all!

 

I'm using SuperTech 85/140 - I asked ECGS since they recommend Lucas and stress using non-synthetic, and they said SuperTech was fine. They said it's more important to change it often than what brand you use.

 

I spoke with ECGS today and they said 75/90 or heavier syn was ok as well and could extend change interval. Go figure, it's like we are on our own!

 

That’s surprising, ECGS wrote a whole big thing about why one shouldn’t use synthetic.

I run conventional 85W-140 from Torco.

 

I have a 98 Grand Cherokee with a True -Trac and they were hawking the same 85W-140 Lucas but could never really rule out a synthetic either. Murky waters at best.

 

By the way, Ford Motorcraft 75W-140 gear oil has no additives and I'm thinking I'll use it with the 5.29 gears. I also asked ECGS about additives and they said it made no difference with our Toyota's!

 

It’s not a critical choice really in any vehicle. They’re just gears. Generally speaking, thicker protects better under load and when warm. Thinner protects a bit faster in the cold and provides a bit more efficiency. With a low gear ratio and the teeth spinning quickly, I like a thicker cushion between them. But you could run an 85 or 90 weight fine if you wanted to.

I don’t think synthetic is evil, but I’ve had more leak problems with it than conventional so I stick to conventional. A Nissan axle I had insisted on leaking with 75w-140 and the exact same axle with no other changes didn’t leak for 20k miles afterward with 85w-140 conventional. It’s only an anecdote but it was enough of a headache at the time for me to be set in my ways now. I order cases of 12 liters at summit racing so it’s easy to just keep doing what I do.

 

I did the opposite of everyone. REM and Cryo, did not break in the gears or change the fluid. Towed my camper immediately up steep mountain grades. It’s been 20k miles using 100% Synthetic Amsoil Severe Gear

$29 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90 and the gears are silent.

 

So you have been using

$29 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90 instead of the heavier weight while towing and have had no problems. I'm in Florida that might make it worse I dunno! Where are you located?

 

I did REM polishing on mine and also use the Amsoil severe gear 75-90. No issues at all. In San Diego.

 

Any 2.7L 6 speed auto guys geared to 5.29? How is it on the highway?