Transmission damage: myth or substantiated truth tire size, going 265 to 285's.

My Nittos have about 5,000 left on them or so. I could go longer, but I'm a dirty gal....stop it-don't go there....and like to get a little mud on the tires. The Nittos never did do very well in the snow off road. Great on pavement I-80 up to the Sierra's etc. Got me stuck a few times in the deep stuff but I know that is also a clearance issue.

I went wheeling with a few who are running 285/70/17 and the tires just look sick on there! I love 'em! The 265's after the lift just look too small. And again, trying to ink out every bit of clearance I can get with out going over board on suspension parts. I have a great buddy who is a Master Toy Tech and he told me to stay with the 265's. He said the true weak point is the transmission, and it's starting to be documented that the tire sizes over stock are doing damage. Now, he should know right? He fixes these things.

I want to know if any of you that have gone to 285's are seeing any changes to wear and tear on your rig.

I can tell you, my 6 speed transmission does have a funny catch to it around 2nd gear. If she's cold and I have to stomp on it out of my road way onto the 50 mph main road, I've felt her hit 2nd or 3rd pretty hard. I've also noticed when I'm wheeling at a low speed for a long time, that first time I shift out of 1st and into 2nd, the shift is rougher compared to the other gears. I've decided I'm going to get MT's, Hankook Toyo or Goodyears, but I still haven't decided on the size.

My one other thought.....for now, look for another decent 265 AT. Work on getting a set of 285 MT's on another set of rims that only go on there for off roading runs. More expensive now, but not in the long run perhaps. And down the road, some aftermarket UCA's. Probably around the time the suspension is due for a change out.

So, if you are running 285's as your primary tire...how she doing? Thank you very much,
Melinda

I've had 285's for a little over a year, and I've never heard of transmission issues accociated with them. The most common issues with the larger tires is front-end related- ball joints, CV joints and the steering rack.
If you're over 125k and want to run 285's, I'd say put lower ball joints on the "to-do-soon" list, and get yourself a set of Poly Steering Rack Bushings from toytec.com. That should do ya well. :hatsoff:

What tires are you interested in?



Oh...and post some pics when they're installed!

Ruffian said:

I can tell you, my 6 speed transmission does have a funny catch to it around 2nd gear. If she's cold and I have to stomp on it out of my road way onto the 50 mph main road, I've felt her hit 2nd or 3rd pretty hard.

Click to expand...

You're 5 speed is probably doing just fine. A few things come to mind:

- In low range the shifts will feel rough/abrupt. (Duh, you know that)
- I find that an occasional reset of the computer for the transmission helps. To do this go into the fuse box by the battery, remove the fuses labeled 10A ETCS and 20A EFI for a few minutes (vehicle off, key off). Why? Both the engine and the transmission 'learn' your driving style and sometimes they take home the wrong message When you go to to restart the truck turn the key on, count to 10 then turn to the start position or it may sputter and stall on the first attempt.
- Finally, turning worn, soft or aggressive 265/70's (or 285's especially) is akin to pulling a small trailer in terms of drag. The transmission is programmed to shift a little quicker and a little firmer (to avoid heat build up) under a load. I don't think I'd be too worried about it.

You are definitely working the trans a bit harder especially if you drive aggressively and off-road. I would think you're a good candidate for regular fluid changes. Your V8 T4R already has an external trans cooler so you should be fine with that. (The V6's, IMHO, benefit from adding a cooler similar to your V8's.) Based on what I know of your usage I would do the trans fluid every 45k-50k. If you keep the trans, t-case and axles full of fresh, clean fluid I wouldn't worry about it. I think resetting the computer will improve it for you.

Good luck, let us know how it goes.
:cheers:

TY Chris. I'll give that a go. Yeah as soon as those Nitto's hit 30,000 the rig is just responding differently all around. I'm good on all the fluids, fully syn. and all. lol, I know I know...5th speed....that was 3 am and I was getting loopy and hadn't found anything with my transmission research.
I agree and think the "learn' needs to be reset. Thank you very much for the write up on it!! I'll give it a go and let you know.
Ruffian just hit 91,000 this week. (Went up to Tahoe and played in the last spring snow storm.) Thank you LINY for the recommendation for those parts. I love Toytec! Both CV joints are new. Installed just after my OME lift in 2008. I will be getting 285's, and I do have a body shop friend who's going to supervise my plastic trimming. I'm leaning towards the Hankooks or Goodyear Wrangler Duratraks. (MT's) If I had my druthers and a sugar daddy, I'd get the BFG KM2's. Nothing at all against Nitto or Toyo, but the rubber compound is too soft for the sharp rocks around here. I have lots of slices and chunks missing, but they did great cost wise and I'd use them again on a non 4x4 vehicle. Well...not so good in slushy deep snow, but that's to be expected. Thanks again Gents!:thanks:

CJ3Flyr said:

You're 5 speed is probably doing just fine. A few things come to mind:

- In low range the shifts will feel rough/abrupt. (Duh, you know that)
- I find that an occasional reset of the computer for the transmission helps. To do this go into the fuse box by the battery, remove the fuses labeled 10A ETCS and 20A EFI for a few minutes (vehicle off, key off). Why? Both the engine and the transmission 'learn' your driving style and sometimes they take home the wrong message When you go to to restart the truck turn the key on, count to 10 then turn to the start position or it may sputter and stall on the first attempt.
- Finally, turning worn, soft or aggressive 265/70's (or 285's especially) is akin to pulling a small trailer in terms of drag. The transmission is programmed to shift a little quicker and a little firmer (to avoid heat build up) under a load. I don't think I'd be too worried about it.

You are definitely working the trans a bit harder especially if you drive aggressively and off-road. I would think you're a good candidate for regular fluid changes. Your V8 T4R already has an external trans cooler so you should be fine with that. (The V6's, IMHO, benefit from adding a cooler similar to your V8's.) Based on what I know of your usage I would do the trans fluid every 45k-50k. If you keep the trans, t-case and axles full of fresh, clean fluid I wouldn't worry about it. I think resetting the computer will improve it for you.

Good luck, let us know how it goes.
:cheers:

Click to expand...

Everything in the drive train is effected by fitting larger tires. The transmission, transfer, prop shafts, diffs, axles and brakes. They all experience greater loads because the tires are heavier and the larger diameter increases the torque values over all driving parameters. Generally everything can easily cope with a small increase, but it's a fact that all components are now operating slightly above their 'normal' range. Unfortunately it's virtually impossible to predict when/where/if something might go bad.

The good news is this can easily be remedied by adjusting the gear ratios in the drive train. There are lots of online calculators and charts available to help you choose the right ring and pinion ratios for the tire size you have. Here's one Differential Gear Ratio Chart - Tire Size to Gear Ratio
If you are going from a 31 to a 33 and your gears are currently 3.91's then to keep things close to stock then regearing to 4.1 or 4.3 is a great solution.

Oh my goodness....so I start for larger tires to get the last bit of clearance out of her without going gonzo on my daily driver. Now I'm considering spacers, how to get a 285 into the spare, the plastic trimming...and now regearing. Like I even know how to do that. Sigh....Thank you techno...more food for thought.

techno said:

Everything in the drive train is effected by fitting larger tires. The transmission, transfer, prop shafts, diffs, axles and brakes. They all experience greater loads because the tires are heavier and the larger diameter increases the torque values over all driving parameters. Generally everything can easily cope with a small increase, but it's a fact that all components are now operating slightly above their 'normal' range. Unfortunately it's virtually impossible to predict when/where/if something might go bad.

The good news is this can easily be remedied by adjusting the gear ratios in the drive train. There are lots of online calculators and charts available to help you choose the right ring and pinion ratios for the tire size you have. Here's one Differential Gear Ratio Chart - Tire Size to Gear Ratio
If you are going from a 31 to a 33 and your gears are currently 3.91's then to keep things close to stock then regearing to 4.1 or 4.3 is a great solution.

Click to expand...

Don't dispair. Take a deep breath and accept the fact, you have taken the first steps down the road to eternal happiness through excessive offroad modifications...

techno said:

The good news is this can easily be remedied by adjusting the gear ratios in the drive train. There are lots of online calculators and charts available to help you choose the right ring and pinion ratios for the tire size you have. Here's one Differential Gear Ratio Chart - Tire Size to Gear Ratio
If you are going from a 31 to a 33 and your gears are currently 3.91's then to keep things close to stock then regearing to 4.1 or 4.3 is a great solution.

Click to expand...

With a 4th gen, I really don't think you need regear just to go to 285s because your 4.0 V6 is a lot more powerful than a 3rd gen 3.4 and will push those tires fine. That's coming from someone who has regeared a 3rd gen to run 33s. If you do end up regearing anyways, going from 3.90s to 4.10s would be virtually unnoticeble and a total waste of $1500+. 3.90s to 4.30s would be a marginal difference, still not worth the $$ IMO and AFAIK, aftermarket companies don't make 4.30s for those diffs so you'd have to find used Toyota gears or spend a fortune on new ones.

If you're gonna spend that kind of dough, go to at least 4.56s and even better - 4.88s.

brian2sun said:

If you're gonna spend that kind of dough, go to at least 4.56s and even better - 4.88s.

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*sigh* my holy grail is the 4.88 locked front and rear...

Just get it over with and get some 5.29 gears. Then you can slap on some 36" or so tires.

Hell, you might as well just get some 5.71s, 40s, and dual t-cases! Now we're talking!

brian2sun said:

Hell, you might as well just get some 5.71s, 40s, and dual t-cases! Now we're talking!

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well, since you are doing all that, just SAS it!

And make it convertible!

6 speed manny tranny in a 4th gen?

I guess I must have mis-read-you do have a 6 speed manual tranny in your 4th gen or an automatic 5 speed? I would probably consider a 4th gen but I thought I had read and heard that only autos were offered.

I have the Nittos too and I loved them for the first two years and would agree that the downhill side of 30K miles is less enjoyable.

Ruffian that is a good rig name.

techno said:

Don't dispair. Take a deep breath and accept the fact, you have taken the first steps down the road to eternal happiness through excessive offroad modifications...

Click to expand...

LMAO! Yeah....explains why I spend all my extra money on stuff for Ruffian instead of slinky new shoes and sexy dresses, drinking beer and playing in the dirt with my off road clubs, spending my vacation time planning historical SUV trips for the general public instead lying on a beach somewhere, and how I spend my time getting my manicure redone because the cleaner for Ruffian's throttle body ate through my 2 pairs of rubber gloves. I wouldn't trade any of it. I took that deep breath 2 years ago when I drove her off the lot.

Ron Helmuth said:

I guess I must have mis-read-you do have a 6 speed manual tranny in your 4th gen or an automatic 5 speed? I would probably consider a 4th gen but I thought I had read and heard that only autos were offered.

I have the Nittos too and I loved them for the first two years and would agree that the downhill side of 30K miles is less enjoyable.

Ruffian that is a good rig name.

Click to expand...

If my previous comment didn't convince you, I am a bit of a ruffian myself. And I've always loved horses and she was a hell of a good filly. Yeah I can't wait to get new tires. RE: the gears...that was 3 a.m. brain mush talking. 5 forward and one in the opposite direction....thus 6 which isn't the correct way to state your transmissions ability. My bad. I'm a girl...I get one mistake here ...k? lol

Oh and Ruffian will be SAS'd if I buy another daily driver....ha! after I win the millions..... What I need to do is get a dedicated trail pony. One that someone has already done all the gearing, lockers, winch etc. His name is going to be Bucephalus.

brian2sun said:

With a 4th gen, I really don't think you need regear just to go to 285s because your 4.0 V6 is a lot more powerful than a 3rd gen 3.4 and will push those tires fine.....

Click to expand...

I agree, the engine is up to the job, but the regearing is a solution to the issue that Ruffian was asking about, that being transmission or other damage from the extra forces.

I think she currently has 3.727's so switching up to 4.1's would make a positive difference and be ideal as a daily driver. But if this rig is headed for offroad fame, then yes, 4.56's are definitely in her future.