Gear change

Talked to Keith at BAMufflers. He recommend a resonator to improve sound of exhaust when towing. The surprise came when we started talking about mpg. According to him changing to a set of 4.88's will actually improve-mileage. He explained how it works but I did not catch all of it. The bottom line is that this somehow fools the mass airflow sensor and computer and actually improves mpg. If anyone has done this I would like to hear your results. Was thinking of gettinga tru trac lsd for rear. Might just save a little longer and get both done. Would like to hear other members experiences with trying to improve mpg. Would like to hear what works and what doesnt.

 

I'm interested as well.

 

@davesnothere just got his. I'm sure he's gonna let us know if his mpg's change

 

Headin to the coast for Thanksgiving, about 250ish miles round trip, gonna fill up before I set out. I'll let you know, before I was at about 9 mpg. Gonna be doin about 65mph, I can see a difference already but I gotta chalk it up to having the nannies on and babying it till break in is over

 

So just got back from port Aransas. Mpg is up 1 on dashboard. Went from 9 to 10. I think it's more. It used to take me a half tank to get there, it only took about 3/8s, drove around a lot down there and still made it home on one tank. On the hills there was no more searching for a gear to get it up the hill, it just got up. Over all I'm am extremely happy with having the power back and the mpg up

 

You went to 488 gearing. If you dont mind what was total cost and do you think it was worth the expense

 

Total was just under $2800. To me it was worth to have the power back, don't care to much about mpg but it's a bonus. Plus the strain that won't be on the engine is good, too. Put on the tow/haul tonight for a sec to just see the difference and it was great. Need to change fluids on Monday and then I can stomp it as it is just over 500miles, which was break in and I baby'd the shit out of it. I got passed by a freakin Prius

 

I knew if its done for gas mileage its way long on the payback. But im looking for performance and better towing performance. With 20 in wheels and basically 33in tires. I think this would be a good upgrade. Will have to save for about 6 months to do it. Did you use yukon gear set from dirty deeds. It says your down in south tex. Im in san antonio so i figure cost will be pretty close to the same for me. I really want this upgrade now that i know it works. Hope you keep posting for a while to see how it works out for you overall

 

This statement makes no sense; changing the gears changes how much the input pinion rotates compared to the output. If you had large diameter, massive tires deeper gears would help keep your overdrive gears more usable but with only 33" tires you'd just run your engine at a higher RPM for no reason. 33" tires are pretty much a stock size so there's not much difference in mass or inertia. 4.30 gears are already pretty deep and do well with my LT285/70R18 (34x11.5") Nitto Exo Grapplers. I don't think that I would want 4.88 gears unless I went with at least a 35 or 37" tire.

 

@balou , I'm also in SA, I went with the gear guy out of spring branch. He ordered the parts for me(Yukon gears and everything), so that if anything went wrong he had to deal with it and not me. He will do other gears such as Nitro but then you have to deal with them if anything goes wrong or whatever with gears. I like having the peace of mind that if anything goes wrong I just take it there and no worries, all under warranty. Do not goto Thrash gears, overpriced. If you don't want to drive out of town try 87 gears, I've heard some good about them but got the most recommendations for the Gear Guy

 

Did you reset the mpg display? Also, what's the engine spinning at hwy speeds?

 

No, I didn't reset, it was at 9 and moved up to 10. Rpms were 2k at 65-70mph. Usually drive 80-85 but babying gears till gear oil change

 

I noticed you are running 35's. Im running 33's. I was thinking about doing the gear change to help with towing. But with basically stock tires i wonder if i would get the same benefits as you. Need to talk or hear from someone who has more knowledge to figure if it would hurt me or help. If i do it. Im going the same route as you and getting it done right. I tow a 25ft travel trailer and problems while traveling ia the last thing i want

 

I now it doesnt make sense. Like i said i didnt catch or understand all he told me. To a higher numerical value increases rpms and lowers mpg. Since my tundra only gets used on weekends. I tow a 25ft trailer about 80% of the time. He thought that the gear change would be better as far as towing goes and mpg return would be minimal. I dont know enough to know wether it will help me or hurt me. So i would like to hear from other people and get more info before i finally pull the trigger on this upgrade

 

Great chart according to gear ratio and tire size im right in the sweet spot for good overall performance. The 488's would help with towing but reduce mpg. Well for now that settles that issue for me unless i get bigger tires. Its best for me to stick with the 430 gear ratio. Thanks for help and info.

 

No i think what im looking for is to tow with a gas engine and get deisel performance. Im just going to have to accept the fact that is not possible. The tundra has no problems towing but like everyone who modifies their truck. We can make it better.

 

Has anyone changed to 4.88 gears with the 4.6L engine. I pull a 25' 5000lbs travel trailer and 65mph in 4th gear is workable with the stock 275/55/20" tires. Would changing to the 4.88 setup give a better transmission performance under load. I think the 4.88s would solve the gear search issue and still provide a gear up and a gear down in a acceptable rpm range. In the stock setup I can almost pull 5th but even the slightest incline or head wind sends the trans into the gear of the moment thing. Otherwise it is a wonderful truck and no I do not want a diesel. Been there before and unless you pull all the time you can never make it pay.