Transmission questions (1 Viewer)

[hammerheadfistpunch]

1. Shifting hard. especially between 1 and 2. What should I look for? Fluid appears to be at the right level and its the right color and smell. I wonder if it's just a little low. Any other things I should look at? It was rebuilt by the PO at something around 150k according to them and it's at 325k now. It doesn't slip, it always shifts consistently, and I have played with the pressure cable and in factory spec it does it, and if I add more slack it doesn't change. Feels like too much line pressure, because if I ease up on the throttle it shifts smoother. It's also better cold then hot.

2. Are there any mechanical differences between a UZJ100 A343F and an FZJ80 A343F besides the bell housing and presumably the torque converter? I noticed the 80 series transmission is out of production and you have to go reman or pay a lot. The 100 series transmission is still in production and quite reasonable in price.

 

[shocktower]

1. Shifting hard. especially between 1 and 2. What should I look for? Fluid appears to be at the right level and its the right color and smell. I wonder if it's just a little low. Any other things I should look at? It was rebuilt by the PO at something around 150k according to them and it's at 325k now. It doesn't slip, it always shifts consistently, and I have played with the pressure cable and in factory spec it does it, and if I add more slack it doesn't change. Feels like too much line pressure, because if I ease up on the throttle it shifts smoother. It's also better cold then hot.

2. Are there any mechanical differences between a UZJ100 A343F and an FZJ80 A343F besides the bell housing and presumably the torque converter? I noticed the 80 series transmission is out of production and you have to go reman or pay a lot. The 100 series transmission is still in production and quite reasonable in price.

Check the kick down cable adjustment is not in bad shape inside the box these things last forever

 

[hammerheadfistpunch]

Check the kick down cable adjustment is not in bad shape inside the box these things last forever

Kickdown cable is the pressure cable I was referring to. Seems to travel fine, but no adjustment seems to help.

 

[OGBeno]

100 series A343F won’t work.

 

[flintknapper]

Kickdown cable is the pressure cable I was referring to. Seems to travel fine, but no adjustment seems to help.

Is this something that has suddenly started (harsh 1-2 shift)?

If the kick-down cable has no effect.....I would be inclined to check the line pressure. There is a service plug you can remove and hook a pressure gauge to. Should be on the side of the housing a bit in front of the dip stick IIRC. At idle (in Drive) your pressure should be between 61-70 psi. In Reverse....74-88 psi.

IF those are within spec, I'd continue on taking pressure readings at Stall Speed: In Drive (128-153 psi) In Reverse (158-193 psi).

If any of these are significantly higher then I'd drop the pan and look to see if the Primary Regulator Valve has been 'Boosted' to the high position. This by itself shouldn't cause harsh shifting but in conjunction with a maladjusted kick down cable or sticky accumulator could suddenly become noticeable.

There is also a Line Pressure Control Solenoid that could cause problems. But you've got to begin testing/diagnosing somewhere.

I'd revisit your kick down cable first and be sure it is correct. Adjusting that one direction or the other should create a noticeable effect.

I built a pressure gauge set (many years ago) with an 8' hose on it so it will reach all the way up to the windshield where I can observe it. That way you don't need a second person to watch the gauge(s).

 

[Vasiliy]

Check Throttle position sensor too, before you go through trans

 

[hammerheadfistpunch]

Is this something that has suddenly started (harsh 1-2 shift)?

If the kick-down cable has no effect.....I would be inclined to check the line pressure. There is a service plug you can remove and hook a pressure gauge to. Should be on the side of the housing a bit in front of the dip stick IIRC. At idle (in Drive) your pressure should be between 61-70 psi. In Reverse....74-88 psi.

IF those are within spec, I'd continue on taking pressure readings at Stall Speed: In Drive (128-153 psi) In Reverse (158-193 psi).

If any of these are significantly higher then I'd drop the pan and look to see if the Primary Regulator Valve has been 'Boosted' to the high position. This by itself shouldn't cause harsh shifting but in conjunction with a maladjusted kick down cable or sticky accumulator could suddenly become noticeable.

View attachment 2637848

There is also a Line Pressure Control Solenoid that could cause problems. But you've got to begin testing/diagnosing somewhere.

I'd revisit your kick down cable first and be sure it is correct. Adjusting that one direction or the other should create a noticeable effect.

I built a pressure gauge set (many years ago) with an 8' hose on it so it will reach all the way up to the windshield where I can observe it. That way you don't need a second person to watch the gauge(s).

View attachment 2637853

This is great stuff, I knew about the primary regulator valve, but haven't been in there to mess with it. Its always been a little firm, but lately its bordering on obnoxiously harsh.

 

[hammerheadfistpunch]

100 series A343F won’t work.

Different mechanically? Electrically? just shape? It's the same AW30-43LE isn't it?

 

[OGBeno]

Well, you already have the information. The internet is a great place to chase this information down.

It’s been asked before... many time.

 

[flintknapper]

This is great stuff, I knew about the primary regulator valve, but haven't been in there to mess with it. Its always been a little firm, but lately its bordering on obnoxiously harsh.

The reason I ask is that you stated the P/O rebuilt the transmission, some time prior.

It's possible they bumped up the line pressure and/or installed a 'shift kit'. All it would take is for one check ball to get sticky to cause your problem.