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overdrive transmission


auraman

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Auraman here,

I have a 87 dolphin with overdrive. The overdrive may work for 100 miles then shut off with 4 or 5 quick on again off again shifts up and down, and then will refuse to work for 1000 miles or so. Then the overdrive seems to work great. The cycle then repeats it's self all over. I thought maybe the engine was hot on a few cases but the last time it happened that could hardly be the case. Any thoughts on this?

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Most of us with auto, just leave the O/D off unless you have a big tail wind or are going down hill.

Folks with temp gauges on the trannie report a large increase in transmission temp when using O/D

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  • 3 weeks later...

wme (or others)--

Re: Leaving the OD off-- if it's not shifting into the higher gear regularly does it still build a higher temp? Or just when it's going from OD and back again?

I just brought one back to Minnesota from Nevada and could manaage a lot of times to avoid it shifting back and forth on level roads but it definitely wasn't something that could be used all the time and maybe not much per those of you that have a lot more experience?

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Well this is going to go against what everyone els has to say. But first let me make it clear that I am not saying everyone is wrong, I am running a different transmission than most, a A340F (behind a 22r turbo in a 4x4) and transfer case. Thats what its supposed to have for the year and engine but the firewall tag says A340H ( supposedly behind a v6 in a 4x4} so I am not totally sure. It does though have a locking torque converter. Any how for me what I have found is that I can look at my transmission temp gage when running with overdrive off and the temp can be high, say 220 or so even when cruising down the freeway at 60 mph+. I will turn the od on and it will drop rpm's and I can actually watch the needle fall to a lower temperature and when I say watch you can actually follow it with your eyes. I never see temp increase when using over drive but it is hard to keep the speed up unless on level ground with no head winds. What drives my temps up are curvy roads where you are on and off the gas, city traffic and sustained long climbs. I have never seen od to raise my temp only lower it.

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I am running a different transmission than most, a A340F (behind a 22r turbo in a 4x4) and transfer case. Thats what its supposed to have for the year and engine but the firewall tag says A340H ( supposedly behind a v6 in a 4x4} so I am not totally sure.

Hi Greg, I,m not positive on the auto equipped rigs but it stands to reason as the 22RET trucks used the same 5spd manual as the V6 trucks.

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HI,

I agree with Turbo Greg, it seems weird that an OD tranny would run hotter with OD on since your RPMs are lower. There could be any number of things wrong, I would take it into a tranny specialist. or at least ID your tranny so you can get get a better idea of issues it might have.

If you think your tranny is running hot, try installing a transmission temp gauge. Most info that I have read indicates that your tranny should run at <225 degrees. If your tranny is running hot I would suggest a tranny cooler.

Here's a chart from TCI's website http://www.tciauto.com/tech_info/trans_life_expectancy.htm

I got this off of the Toyota timeline at http://www.4x4wire.com/toyota/faq/

1986 Toyota Pickup & 4Runner

More new innovations were available from Toyota in 1986. The solid front axle gave way to a new independent front suspension (IFS) utilizing torsion bars and a-arms. This new suspension housed a differential with a 7.5" ring gear and 1 1/8", 27 spline axle shafts. A turbocharged 22RE was added to the available 22R and 22RE to compete with Nissan's new V6 powered pickup. The 22RTE was available with an R151F 5 speed manual transmission in the pickups only, or a 4 speed automatic A340H as an option in pickups and standard in 4Runners. The R151F came backed with a RF1A gear driven transfer case equipped with a 23 spline output shaft instead of the standard 21 spline shaft. This transfer case utilized a "forward" shifter in models with bench seats, while pickups equipped with buckets had a top shifting transfer case. 22R motors once again came backed by G52 or G54 5 speed manuals and "forward" shift RF1A gear driven transfer case. The 22RE was available with either a W56 5 speed manual and top shifting RF1A 21 spline gear driven transfer case or a A340F 4 speed automatic tranmission with a VF2A chain drive transfer case. Other mechanical changes for 1986 were optional automatic hubs and a standard 3" wider 8" solid rear axle with larger (10") drum brakes and axle tubes. The automatic used with models equipped with automatic hubs was the A340H 4 speed automatic transmission came with an electronically controlled integral transfer case. A digital dash was optional on the turbo 4Runner and all turbo models came equipped with a stronger four pinion rear differential.

1987 Toyota Pickup & 4Runner

No significant model changes were made for 1987.

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Transmission overheat when using od has been a reacurring subject on the yahoo toyota campers group. It looks to me that the over heat issues are related to the 22r fuel injected engines which use a transmission that does not have a locking torque converter. I can not remember though anyone who has a temp gauge posting any data that they actually see the high temps when using overdrive. I might bee wrong on that though as I do not continuissly follow the postings there. With my transmission the torque converter goes into lockup when overdrive and remains there. It will seek 4th gear when needed but never go out of lockup. Remember I am talking about the 4x4 setup and not 2 wheel drive. 2 wheel drive uses a different transmission and may be a complete different ball game.

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The problem child is the older NON lock up trannie. In O/D even though the engine is turning less RPM, the drag of a M/H causes you to press the throttle down more. With the increased torque the converter slips more and that is what makes the heat. If you have a lock up converter then no slip and no extra heat.

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That brings up a good point. Since we know there was an issue with overloading the chassis, it would only seem logical that the transmission (and engine) would suffer too.

I haven't seen much on the net relating to Toyota torque converter and automatic transmission upgrades (like shift kits and bearing upgrades).

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  • 12 years later...

My 87 r22e mh  automatic tranny was working great with overdrive on down side of hills and with good tailwind but it just stopped going though Texas. lil rig got me to arizona in 3rd no problem. just wondering what my options are? like will tranny eventuaqlly die or  can i run it without OD?

should i take it to transmission guy om Phoenix- any recommendations?

thx

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I've been driving my automatic with overdrive off for 14 years. Overdrive can cause the trannie to run hot and cause problems. Overdrive also cuts off at 4000 ft. I know some of that drive is high desert and might have been above the limit. 

Linda S

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  • 2 months later...

I added water to my radiaotor as it was low and the manual said the sensor or a sensor had to reach certain temp as in hotter for the OD to kick in and so it worked from Tuscon oer to Phoenix and all way to San Diego and back to Phoenix, well not up hill but downhill and on flat road with tailwind. 60-65

had to add transmission fluid in Palm Spring on new years day there was a small leak and I guess it just got low.

All good now.

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