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Transmission in Tacoma fixed - kinda

Posted By: Paul Dobbins

Transmission in Tacoma fixed - kinda - 04/11/20 02:50 AM

I had AAMCO do the work on the truck. They rebuilt that 5sp manual transmission around 176,000 miles ago, and figured I'd let them have a go at it again. They found a used transmission with around100,000 miles on it for $1100. I said go for it. Well, I got the truck back on Wednesday. It seemed to drive well when I drove it home. I took it beaver'n on Thursday and noticed it used a lot more gas than normal. So today, I figured the mileage. Before the transmission repair, I averaged 17mpg. After the transmission repair, I averaged 12mpg. It was a puzzlement to me, so I called my retired Toyota mechanic friend and asked him why it would do that. He figures they put in a transmission from a 4 cylinder, which has different gears than the transmission for a 6 cylinder. I'll make a trip back to AAMCO to get this straightened out.
Posted By: hippie

Re: Transmission in Tacoma fixed - kinda - 04/11/20 02:55 AM

It'd have to be way off to make that big of a difference I'd think.

Has me puzzled too, maybe they damaged an oxygen sensor or something. Strange one.
Posted By: Anonymous

Re: Transmission in Tacoma fixed - kinda - 04/11/20 03:06 AM

Wow 17mpg prior to the repairs?? Seems steep for a newish Toyota. I’ve had several older Toyotas, granted non with a v6 but 17mpg?? One 85 I had with a 22r 5.29s and 49 inch tires, ran out at 20 mpg...I could also cruise at 70 on the hwy. Wife has an 05 Chevy 1500 4x4 4.8 v8 and she gets 20-22mpg on the hwy.
I have always been under the impression that newer vehicles were to be better economically?
Posted By: Paul Dobbins

Re: Transmission in Tacoma fixed - kinda - 04/11/20 03:09 AM

Originally Posted by Wylee
Wow 17mpg prior to the repairs?? Seems steep for a newish Toyota. I’ve had several older Toyotas, granted non with a v6 but 17mpg?? One 85 I had with a 22r 5.29s and 49 inch tires, ran out at 20 mpg...I could also cruise at 70 on the hwy. Wife has an 05 Chevy 1500 4x4 4.8 v8 and she gets 20-22mpg on the hwy.
I have always been under the impression that newer vehicles were to be better economically?


Not a new Toyota - lol - 20 years old. This is a 2000 model with 677,000 miles on it.
Posted By: Huntall76

Re: Transmission in Tacoma fixed - kinda - 04/11/20 03:13 AM

Maybe your catch was weighing your truck down.
Posted By: Paul Dobbins

Re: Transmission in Tacoma fixed - kinda - 04/11/20 03:14 AM

Originally Posted by hippie
It'd have to be way off to make that big of a difference I'd think.

Has me puzzled too, maybe they damaged an oxygen sensor or something. Strange one.


The 4 cylinder has a different model number transmission than the 6 cylinder. Supposedly the gears are different sizes in the two different transmissions.

4 cylinder - 330303D410
6 cylinder - 15398914

Posted By: Canvasback2

Re: Transmission in Tacoma fixed - kinda - 04/11/20 03:16 AM

Did they try remapping the transmission ECU ?
Posted By: Anonymous

Re: Transmission in Tacoma fixed - kinda - 04/11/20 03:17 AM

Ok ok, I’ll give it that...I will also admit that 85 I had had been gone through almost completely. All but the body...it was built to be crunched on the trails. Engine and drive train was all rebuilt or new.
I am thoroughly impressed by your mileage at any rate.
Posted By: Paul Dobbins

Re: Transmission in Tacoma fixed - kinda - 04/11/20 03:20 AM

Originally Posted by Canvasback2
Did they try remapping the transmission ECU ?


Do they do that for a manual transmission in a 20 year old truck? I have no idea what remapping is - lol.
Posted By: hippie

Re: Transmission in Tacoma fixed - kinda - 04/11/20 03:22 AM

I don't doubt they're different ratios, but i think you would know if they were far enough apart to make that big of a difference in fuel mileage. Like engine sounding like you need to shift again, ect.
Posted By: Leftlane

Re: Transmission in Tacoma fixed - kinda - 04/11/20 03:30 AM


is there any chance you can smell the clutch burning / slipping? That would explain the drop in mpg.
Posted By: Anonymous

Re: Transmission in Tacoma fixed - kinda - 04/11/20 03:48 AM

Try marlin crawler, advance adapters and trailgear for info on gear ratios. Seems like I’m forgetting a few others to check. But I know there’s a website that has all this info for parts swaps and such for the Toyota nuts. For example if your gonna swap up to a better trans for say crawling your gonna wanna know which one to pick by number. In my case the output shaft told me a lot..
Posted By: Anonymous

Re: Transmission in Tacoma fixed - kinda - 04/11/20 03:54 AM

Have fun ogling all the fancy off-road parts while your searching for ratio info;)
Posted By: Paul Dobbins

Re: Transmission in Tacoma fixed - kinda - 04/11/20 04:39 AM

Originally Posted by Leftlane

is there any chance you can smell the clutch burning / slipping? That would explain the drop in mpg.


No, clutch is operating normally. I've put 612 miles on it the past two days and there's no problem, except gas mileage.
Posted By: Bearguy

Re: Transmission in Tacoma fixed - kinda - 04/11/20 04:39 AM

I am going to bet that the speedo drive is different in the two tranny's. Does the speed seem to be close to what the speedometer says?
Posted By: Paul Dobbins

Re: Transmission in Tacoma fixed - kinda - 04/11/20 04:43 AM

Originally Posted by Bearguy
I am going to bet that the speedo drive is different in the two tranny's. Does the speed seem to be close to what the speedometer says?


Yes
Posted By: Anonymous

Re: Transmission in Tacoma fixed - kinda - 04/11/20 04:46 AM

Good call bear guy. I believe there are a few different gears, that said it wouldn’t effect the mileage, just the speedo.
Posted By: Anonymous

Re: Transmission in Tacoma fixed - kinda - 04/11/20 04:50 AM

Well, I guess it could effect your calculations but I think you’d notice a 5mpg difference without math but buy the frequency you’d have to hit the pump.
Posted By: Bruce T

Re: Transmission in Tacoma fixed - kinda - 04/11/20 06:42 AM

Originally Posted by Paul Dobbins
Originally Posted by Canvasback2
Did they try remapping the transmission ECU ?


Do they do that for a manual transmission in a 20 year old truck? I have no idea what remapping is - lol.

X2
Posted By: loosegoose

Re: Transmission in Tacoma fixed - kinda - 04/11/20 11:00 AM

1st, 2nd, and 3rd might be different between a 4 cylinder and 5 cylinder truck. 4th gear's gotta be direct drive 1:1 for both, and 5th gear is an overdrive gear, but the ratio's gotta be pretty close between the two transmissions. Is your cruising RPM pretty close to where it used to be, or is your RPM way higher than before? If your RPM is pretty close, I would suspect the gear ratios are pretty close. The speedometer issue is another possibility. It doesn't have to be too far off to make your trip meter/odometer way off over time, which would give you a false calculation of MPG.
There's likely no reprogramming needed for a manual trans in a vehicle that old.
Posted By: Wright Brothers

Re: Transmission in Tacoma fixed - kinda - 04/11/20 11:12 AM

My first thought was like bearguy. This can be checked by clocking it on a highway with mile markers or have someone follow you and compare.
If it is drinking bad I'd talk to the folks that did the job while still fresh in their mind.
I'm a fan of rebuilding the old trans, but yours was a little worn lol.

Yota guys? Do these have an EGR that gets disturbed during trans R and R?
O2 sensors?
Posted By: Paul Dobbins

Re: Transmission in Tacoma fixed - kinda - 04/11/20 11:30 AM

Originally Posted by loosegoose
1st, 2nd, and 3rd might be different between a 4 cylinder and 5 cylinder truck. 4th gear's gotta be direct drive 1:1 for both, and 5th gear is an overdrive gear, but the ratio's gotta be pretty close between the two transmissions. Is your cruising RPM pretty close to where it used to be, or is your RPM way higher than before? If your RPM is pretty close, I would suspect the gear ratios are pretty close. The speedometer issue is another possibility. It doesn't have to be too far off to make your trip meter/odometer way off over time, which would give you a false calculation of MPG.
There's likely no reprogramming needed for a manual trans in a vehicle that old.


The truck doesn't have a tach. It just has a heat gauge, a fuel gage and a speedometer. I have been running the same basic circuit for the past two weeks with a variance of maybe 20 miles. I normally could make the trip on one tank of gas, but now I have to fill up when I'm about 2/3 through the circuit or I'll run out of gas.
Posted By: Rally

Re: Transmission in Tacoma fixed - kinda - 04/11/20 11:30 AM

I'm guessing the ratio is lower for the new tranny coming out of a 4 cylinder truck. I think Loosegoose had the ratio correct and the first three gears are lower and 4 th is a 1:1 ratio, with 5 th being overdrive and probably lower than should be with a V6.
I was at a Toyota dealership with my son who bought a new Corolla yesterday. Talk about sticker shock! A new Tacoma is 40 grand now, and no single cabs being made, just double or access cabs(1 1/2 cab). I'm keeping my 2005 Tundra single cab with the 8' bed. New Tundra's are too high to work out of and Tacoma's are too small to haul a snomo in.
Posted By: Anonymous

Re: Transmission in Tacoma fixed - kinda - 04/11/20 11:42 AM

Not a Toyota but here is my experience. I had a VW Rabbit 1.4 liter with a 4 speed manual tranny. I got 32 MPG. Wanted more zip so I put in a 1.6 liter with the same 4 speed. MPH went down to 26 MPG. Wanted more zip still and found a 5 speed tranny only to find out it was the SCCA model with close ratio gearing. Got the zip I was looking for but now I was getting 19 MPG no matter how it was driven, high way, town, quick off the line starts or granny roll to get going. No matter, 19 MPG.

I would say that the tranny for the 4 banger in your 6 cyc. is causing the increase. You should see a difference in the RPM's at speed you are traveling. Even a 500 RPM increase over the course of several hours will burn a lot more fuel.
Posted By: Drifter

Re: Transmission in Tacoma fixed - kinda - 04/11/20 12:12 PM

They didn't lock in your hubs on you did they?
Posted By: Albert Burns

Re: Transmission in Tacoma fixed - kinda - 04/11/20 12:39 PM

You may be able to check the model of transmission they installed. If you have the 3.4 V-6 it would need a R-150F,this will fit first Gen. Tacoma's of either 2 or 4 WD vehicles. If they put a 4 Cyl. trans in, the model is a W-59 . You may be able to look at a photo online and try to match it to what they installed. Hope this helps.
Posted By: Lugnut

Re: Transmission in Tacoma fixed - kinda - 04/11/20 01:16 PM

Originally Posted by hippie
I don't doubt they're different ratios, but i think you would know if they were far enough apart to make that big of a difference in fuel mileage. Like engine sounding like you need to shift again, ect.



My thoughts as well. seems like the RPM's would have to be considerably higher at highway speed than with the old transmission.
Posted By: Paul Dobbins

Re: Transmission in Tacoma fixed - kinda - 04/11/20 01:38 PM

Originally Posted by Lugnut
Originally Posted by hippie
I don't doubt they're different ratios, but i think you would know if they were far enough apart to make that big of a difference in fuel mileage. Like engine sounding like you need to shift again, ect.



My thoughts as well. seems like the RPM's would have to be considerably higher at highway speed than with the old transmission.


Something I've noticed about this truck is that a lot of times I can't detect differences in engine speeds. It sounds the same to me when I'm doing 75 as when I'm doing 55. Sometimes I'll be doing 70 mph and will notice that I'm still in 4th gear, and had been for quite a while. It's probably just my old age and poor hearing that causes this.
Posted By: Canvasback2

Re: Transmission in Tacoma fixed - kinda - 04/11/20 02:16 PM

[Linked Image]

Put your Dobbins Lures sign on this truck, and use it as a business income tax deduction !! LOL
Posted By: Lugnut

Re: Transmission in Tacoma fixed - kinda - 04/11/20 02:23 PM

That is a nice looking little truck!
Posted By: waggler

Re: Transmission in Tacoma fixed - kinda - 04/11/20 02:29 PM

Just for reference, I have a '99 Tacoma with a 2.7L four cylinder, that has 370,000 miles, the transmission has never been touched. It still gets 22mpg.
Posted By: billy

Re: Transmission in Tacoma fixed - kinda - 04/11/20 02:32 PM

Paul I feel for ya,its always something aye. gotta be the transmission if that is the only thing changed. they should be able to figure it out....happy easter and good luck on them beaver.
Posted By: Northof50

Re: Transmission in Tacoma fixed - kinda - 04/11/20 02:50 PM

Ever thought of the gas being ; OFF
with all this low barrel head price and fewer people driving the Reserve tanks are filling up, soon the capacity of the tanks will be filled.
Then there is going to be a supply issue of shutting off the well heads.

Try some higher octane fuel.
Posted By: white17

Re: Transmission in Tacoma fixed - kinda - 04/11/20 04:39 PM

Originally Posted by loosegoose
1st, 2nd, and 3rd might be different between a 4 cylinder and 5 cylinder truck. 4th gear's gotta be direct drive 1:1 for both, and 5th gear is an overdrive gear, but the ratio's gotta be pretty close between the two transmissions. Is your cruising RPM pretty close to where it used to be, or is your RPM way higher than before? If your RPM is pretty close, I would suspect the gear ratios are pretty close. The speedometer issue is another possibility. It doesn't have to be too far off to make your trip meter/odometer way off over time, which would give you a false calculation of MPG.
There's likely no reprogramming needed for a manual trans in a vehicle that old.



This sounds real reasonable to me, in theory.
I think what I would do is calculate gallons per hour like is done with fuel consumption in aircraft. Of course you probably don't have a similar record from the old tranny. You need a Hobbs meter or similar to keep track
Posted By: hippie

Re: Transmission in Tacoma fixed - kinda - 04/11/20 05:33 PM

Originally Posted by white17
Originally Posted by loosegoose
1st, 2nd, and 3rd might be different between a 4 cylinder and 5 cylinder truck. 4th gear's gotta be direct drive 1:1 for both, and 5th gear is an overdrive gear, but the ratio's gotta be pretty close between the two transmissions. Is your cruising RPM pretty close to where it used to be, or is your RPM way higher than before? If your RPM is pretty close, I would suspect the gear ratios are pretty close. The speedometer issue is another possibility. It doesn't have to be too far off to make your trip meter/odometer way off over time, which would give you a false calculation of MPG.
There's likely no reprogramming needed for a manual trans in a vehicle that old.



This sounds real reasonable to me, in theory.
I think what I would do is calculate gallons per hour like is done with fuel consumption in aircraft. Of course you probably don't have a similar record from the old tranny. You need a Hobbs meter or similar to keep track


True.

Paul's saying that taking the same trip he has to stop for fuel where as he didn't before.he

I'll be interested to know what the problem/cure is. My money isn't on year ratio tho.
Posted By: run

Re: Transmission in Tacoma fixed - kinda - 04/11/20 05:50 PM

I think my fuel economy is slipping too. I don't drive a Toyota though.
Posted By: hippie

Re: Transmission in Tacoma fixed - kinda - 04/11/20 05:57 PM

I'm driving a '76 Chevy step-van with a 4bbl carburated 350, 4.56 gears that top speed is 55mph and I get 13mpg.
Posted By: lee steinmeyer

Re: Transmission in Tacoma fixed - kinda - 04/11/20 06:11 PM

Originally Posted by Canvasback2
[Linked Image]

Put your Dobbins Lures sign on this truck, and use it as a business income tax deduction !! LOL



Why on earth did they have to start making them look like a dodge. Lost my interest, keep making all the trucks taller, bigger, with a grill that looks like it came off an eighteen wheeler! Auuurrggh!
Posted By: hippie

Re: Transmission in Tacoma fixed - kinda - 04/11/20 06:17 PM

[Linked Image]she

She ain't for sale fella's, my dad bought it new and it only has 32,000 miles on her. It will go 55 p hill and 56 down hill, with the engine screaming! Lol.
Posted By: lee steinmeyer

Re: Transmission in Tacoma fixed - kinda - 04/11/20 06:47 PM

lol, Hippie! I used a frame out of one of those on an old truck I was building.

Paul, are you sure they didn't change the rear end too! lol. That's the only way It would change the overdrive very much. Stands to reason that the overdrive may not be geared as high for a four banger compared to the v-6. The more percentage of overdrive, the more it will pull the engine, because it takes more horsepower. I think that may be the difference, but you would have to find the right tranny. I'm still amazed that it would make that big of difference.
Posted By: 3togo

Re: Transmission in Tacoma fixed - kinda - 04/11/20 06:58 PM

Put your Dobbins Lures sign on this truck, and use it as a business income tax deduction !!

And get 5 years do depreciated it for business use.
Posted By: Paul Dobbins

Re: Transmission in Tacoma fixed - kinda - 04/11/20 08:37 PM

Originally Posted by 3togo
Put your Dobbins Lures sign on this truck, and use it as a business income tax deduction !!

And get 5 years do depreciated it for business use.


Nah, I do the standard mileage deduction. I've been doing that for that Tacoma for the past 16 years with an average deduction each year of around $20,000. That makes around $320,000. in deductions over the last 16 years it has been in use.
Posted By: ratbrain

Re: Transmission in Tacoma fixed - kinda - 04/11/20 08:45 PM

That truck owes you nothing brother!!!
Your testimonial, Rally's and others is the reason I believe my next truck is a Toyota!
Maybe the gas mileage is down on the return trip-too many beavers?? Just kidding Paul!
Posted By: Jtrapper

Re: Transmission in Tacoma fixed - kinda - 04/11/20 09:46 PM

release the emergency brake! lol.
Posted By: Rally

Re: Transmission in Tacoma fixed - kinda - 04/11/20 09:46 PM

I hear that Lee. I spent a couple hours at the dealer yesterday trying to figure out how to cut the center hood out of a 4 door Tacoma to get a standard cab! I figure in about ten years when I need a new truck, there should be plenty of todays models in the bone yard for a wreck and repair job. Dealer said there is a new body style of Tundra coming out next year.
Posted By: ratbrain

Re: Transmission in Tacoma fixed - kinda - 04/11/20 10:47 PM

Wife and I just got back from the dealer (they're closed) she liked the access cab-6 ft bed much better than the 4 door. Plain Jane truck with the I-4.
Posted By: Anonymous

Re: Transmission in Tacoma fixed - kinda - 04/11/20 11:13 PM

I’m struggling to believe this but I was googling around and read that you must have the correct model year transmission because apparently there IS a difference in the signal to and from the ecu. Most of what I was reading was when swapping from auto to manual...but a couple articles were about swapping between manuals. According to the articles I read the ecu can be reprogrammed. Sorry I have no idea how to attach a link.
I’d really like someone to explain to me how an ecu talks to a manual transmission and why?
Posted By: ratbrain

Re: Transmission in Tacoma fixed - kinda - 04/11/20 11:16 PM

.....just scheduled a test drive, they bring it to your house.
Posted By: run

Re: Transmission in Tacoma fixed - kinda - 04/12/20 12:57 AM

Mr. Paul Dobbins, have you installed new spark plugs recently? Or a new air filter?
Posted By: Paul Dobbins

Re: Transmission in Tacoma fixed - kinda - 04/12/20 01:34 AM

Originally Posted by run
Mr. Paul Dobbins, have you installed new spark plugs recently? Or a new air filter?


Yes, but how would that have made a difference after a transmission replacement?
Posted By: Anonymous

Re: Transmission in Tacoma fixed - kinda - 04/12/20 01:39 AM

Isn’t there some kinda law that says everything goes bad at once?
Posted By: run

Re: Transmission in Tacoma fixed - kinda - 04/12/20 01:52 AM

Paul, I was just curious. Sometimes you can improve your fuel economy by installing better quality spark plugs. I'm not a mechanic. I was rolling things over in my mind. I run older used vehicles and you are always fixing something.
Posted By: Team V

Re: Transmission in Tacoma fixed - kinda - 04/12/20 03:23 AM

Might not be transmission at all. I just put new motor in my 1993 Toyota the fuel lines run along frame could they of nick one and be leaking wile under load. I also had the electrical little flapper thing in air box go bad and I got terrible gas mileage.
Posted By: Paul Dobbins

Re: Transmission in Tacoma fixed - kinda - 04/12/20 04:38 AM

Originally Posted by Team V
Might not be transmission at all. I just put new motor in my 1993 Toyota the fuel lines run along frame could they of nick one and be leaking wile under load. I also had the electrical little flapper thing in air box go bad and I got terrible gas mileage.


I thought that might be the case also, but after letting it idle on my driveway for 20 minutes of running there was nothing dripping.
Posted By: Nessmuck

Re: Transmission in Tacoma fixed - kinda - 04/12/20 05:01 AM

Do you have a Tach in the dash ? If so..is the engine reving more at 60 mph than it use to. I know in my truck...on the high way doing 70 mph...my tach is at 2,000 rpm....and it would definitely use more fuel if it was reving at 2500 rpm. But some folks don’t pay attention to that kind of stuff.
Posted By: Tactical.20

Re: Transmission in Tacoma fixed - kinda - 04/12/20 05:25 AM

I think my mileage deduction was about 8,000$ this year, 420k now
Posted By: Paul Dobbins

Re: Transmission in Tacoma fixed - kinda - 04/12/20 11:36 AM

Originally Posted by Nessmuck
Do you have a Tach in the dash ? If so..is the engine reving more at 60 mph than it use to. I know in my truck...on the high way doing 70 mph...my tack is at 2,000 rpm....and it would definitely use more fuel if it was reving at 2500 rpm. But some folks don’t pay attention to that kind of stuff.


No tach. Bare bones dash - speedometer, temperature gauge and fuel gauge.
Posted By: Boco

Re: Transmission in Tacoma fixed - kinda - 04/12/20 03:57 PM

Sell it and buy yourself a new escalade.
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