Early vs. later transmission longevity?

[4wdchico]

I have decided to make my '84 sr5 go away, in whole or in part. if i part it out I'm thinking of taking out the trans & pulling off the diff (ratio does not match my '85 keeper) and putting it up for sale & keeping the rest of the trans/ input gear stack/ transfer case. I have read the info about how the gear ratios are different in the trans as well, but figure that, in a pinch, that would be ok. My real concern is did the early '83-'84 trannys hold up as well as the later updated units? It is a good working trans and I guess that I could get around the $250 I am asking for the whole car for the trans assembly if i sell it as a complete unit.

Any input appreciated.

[SirNik83]

I had a problem with my gauge cluster and needed some parts from the junkyard. I went to all the junkyards in Sacramento, and Stockton, and only found 1 SR5 car. I've never had a problem finding parts before. but I suppose that just goes to show that these cars are getting old.

With that said. if you are going to part it out i'd pull everything that makes in an SR5 and the transmission and rear axle. there are still a lot of tercels in the junk yards. but having a spare set of the parts that make the car special can't be a bad thing.

I don't know much about the later model cars, i can't tell you which ones better. but I can tell you its better then having nothing

[Petros]

I have never heard of a difference. I have seen the early ones go for over 300k miles. The higher gear ratio will mean the trans gears are turning at slower speed (along with the engine), so that might help, but the power through the trans is also going to be the same. Higher speed but lower torque load vs. lower speed with higher torque load.

It is a good question, but I think taking care of it with careful shifting (no "speed" shift), and frequent lube changes with high quality gear lube are more likely to determine longevity than gear ratio differences. If I had to guess, it seems to me lower torque loads would be easier on it, meaning that would be the lower 4.1 ratio. But that is just a guess.

[hberdan]

The transmission on my 1987 DLX 4x4 lasted for 297k miles. The replacement, from an '86 with 254k miles, is still running strong after another 22k miles.
I got rid of a really really rusty 84 SR5 with over 225k miles, but the transmission was running just fine. Should've kept the thing. Oh well.

[Shannon]

I have a 1983 Tercel 4WD wagon.
My first transmission started popping out of gear at about 180k.
I replaced it with a low mile japanese transmission.
I am now replacing that after at 200k more miles.
Problem with this one:
Either the trans oil was not filled properly at a lube place.
Or, it may have been stuck in mud and pulled out improperly, somehow.
The symptom was LOUD TICKING, like a playing card on spokes, in all gears, but
fainter in fourth. It was not the input shaft, that looked fine, as did the external 5th gear. The noise stopped when the clutch was in, but even made the noise when the car was in neutral with the clutch out. The magnetic fill plug had gear teeth stuck to it. So damage to a gear (s) internal definitely.
My experience: they last average 200k. I am replacing with a later year transmission that has the vacumn 4WD switch, but I took that off and I am putting my old 4WD rod back on. And, keeping my front and back axle with the 3.7 ratio.

[4wdchico]

Shannon: You live up the hill from me, I'm in Chico, correct? We spoke about this when I responded to a Craigslist ad about needing a trans I'm pretty sure.

After listening to your car's symptoms my guess is that you have a problem with the gear stack that takes the engine's power down to the trans from the back of the clutch. The bearings that support the counter gear in the stack fail with some regularity. The fact that the noise goes away when the clutch is disengaged is a pretty good sign of this along with the fact that the noise is less in 4th gear, fourth "gear" is not a set of gear at all just the input shaft of the trans being directly coupled to the the output shaft. So when you select "4th" it will serve to tie the two shafts together as one and reduce the noise somewhat.

[SynthDesign]

There should be no difference between trans except for the final drive ratio. They were all made in the same factory for the carried model year runs. Toyota decided to change drive ratios for better gas mileage and higher freeway speed in 84. I'm pretty sure, knowing how Toyota does things, that they were assembled as needed to fit orders, All parts being cast in runs. The markings on the main shaft and other places are the same in my blown 83 trans as the 87 I'm rebuilding.

[4wdchico]

There should be no difference between trans except for the final drive ratio. They were all made in the same factory for the carried model year runs. Toyota decided to change drive ratios for better gas mileage and higher freeway speed in 84. I'm pretty sure, knowing how Toyota does things, that they were assembled as needed to fit orders, All parts being cast in runs. The markings on the main shaft and other places are the same in my blown 83 trans as the 87 I'm rebuilding.

The early c'83-'84 cars had a 3.7/1 diffs, and the '85 up had 4.1/1 diffs. So it was the earlier cars that are better suited to higher speeds and are theoretically capable of higher fuel economy because they have higher overall gearing.

The early cars also had some higher gear ratios in the trans as well EL, 1st and reverse were higher geared than the later cars. So the later cars are much better suited to lower speed mountainous driving. For '85 & up Toyota re-tuned the engine for better low and midrange torque also.

[hberdan]

I certainly concur! My 86 and 87 (now combined into one) drove/drive MUCH better in the mountains than the 84 ever did. It is quite a noticible difference when climbing up steep mountain roads.

[Shannon]

Yes. 4wdChico, greetings.
Well, I had to turn my transmission in as a core, so, I could not tear it apart, as much as I wanted to. But, it sounds like you are correct about the problem. It worked perfectly until the noise started. But, all is perfect again, and it was fun putting the new transmission in.

[4wdchico]

Yes. 4wdChico, greetings.
Well, I had to turn my transmission in as a core, so, I could not tear it apart, as much as I wanted to. But, it sounds like you are correct about the problem. It worked perfectly until the noise started. But, all is perfect again, and it was fun putting the new transmission in.

Good news!

[SynthDesign]

The early c'83-'84 cars had a 3.7/1 diffs, and the '85 up had 4.1/1 diffs. So it was the earlier cars that are better suited to higher speeds and are theoretically capable of higher fuel economy because they have higher overall gearing.

The early cars also had some higher gear ratios in the trans as well EL, 1st and reverse were higher geared than the later cars. So the later cars are much better suited to lower speed mountainous driving. For '85 & up Toyota re-tuned the engine for better low and midrange torque also.

I don't disagree with anything you've stated. I guess I just have had other interpretations. I have found that my 85 with the 4.10 gearing does get better gas mileage especially on the highway doing 65mph. This could be a motor or carb. issue but was repeated with multiple newer T4WDs. My 83 is basically stock and never failed emissions w/ over 244K miles and running strong. In best form highway driving it only gets 32mph. My 85 got 36+ mpg on the same trips. Could be headwind or other variables too. But it was noticeable.

And as for higher reverse gears and first gear. Snohomish Transmission didn't say anything was different when the rebuilt it for me and used mixed parts from an 86 trans to rebuild an 83. I know first and 2nd gears and syncros are out of the 86 trans. I still have the worn out 83 gear parts in a box somewhere. This was a project I wasn't ready to tackle at that point in my life plus they offered a warranty for their work.
Would this cause other issues with the trans?
Premature wear or something else, as I have had no problems with running the trans for roughly 45miles before the rear main seal went on the motor? I am planning to put the trans back in another 83 later when the block is rebuilt.
It would be nice to know if I'm basically setting myself up for a grenaded trans.

Thanks

[4wdchico]

My info on tranny ratios is from a road test article (MT or R&T I think, tried to find it again but could not) that went into the details of the changes for the '85 model year t4wd compared to the earlier years. I remember for sure that the EL, 1st and reverse gears were made lower. i think that 2nd gear was lower also. They went into the tuning of the engine for a more usable torque curve as well.

One thing that I have learned from mixing and matching junk yard Toyota parts for a long time is that the firm tries to change as little as possible. This saves $ and helps with reliability. That being said, I'm pretty sure that if your rebuilt trans worked good for 45 miles w/o gear issues, It should continue to do so for a while. Of course, we both know what may happen if you aggressively bang gears with a 4age installed...

My biggest worry about rebuilding 'yota transmissions is bearing quality. I have seen many rebuilt trannys fail after a short period of time from early bearing failure. This never seems to be a problem with trannys that are rebuilt with genuine 'yota bearings.

Interesting about the fuel economy. It could very well be that the 3ac was working too hard, on the early cars, to propel the the car due to the high gears. I get the feeling that my '84 is too high geared on the freeway and in the hills. The '85 seems to be geared just right about anywhere I take it.

[SynthDesign]

Thanks for your input, Much appreciated.

[Mattel]

check out the "Autocar" UK magazine test thread that I posted in the gallery section. It outlines the differences to transmission and engines for the post '85 Tercel 4wd.