A343F Transmission Refresh (LX450) (1 Viewer)

[matthewscruiser]

I have an A343F transmission (120k miles or so) that I will be installing with a new engine next month. (LX450).

I’m planning to do the following:
- Replace output seal (90311-48016)
- Replace input seal (90311-38020)
- Replace shift solenoids (x2 85420-21090 and x1 35250-50030)
- Replace filter (35330-60020)
- check valve body torque
- Increase line pressure from Medium to High position
- Reseal pan with 1281 FIPG
- Reseal rear extension housing with 1281 FIPG
- Replace ATF inlet/outlet union O rings (x2 90301-11006)
- Top off with fresh fluid

Is there anything else I should consider doing? Has anyone removed the rear extension housing to reseal the FIPG? It looks pretty basic, 6 bolts on back.

I’ll be documenting here. I degreased the exterior yesterday, it was a combination of old engine oil, dirt, and undercoating.

 

[AARONTLC]

I have an A343F transmission (120k miles or so) that I will be installing with a new engine next month. (LX450).

I’m planning to do the following:
- Replace output seal (90311-48025)
- Replace input seal (90311-38029)
- Replace shift solenoids (x2 85420-21090 and x1 35250-50030)
- Replace filter (35330-60020)
- check valve body torque
- Increase line pressure
- Reseal pan with 1281 FIPG
- Reseal rear extension housing with 1281 FIPG
- Replace ATF inlet/outlet union O rings (x2 90301-11006)
- Top off with fresh fluid

Is there anything else I should consider doing? Has anyone removed the rear extension housing to reseal the FIPG? It looks pretty basic, 6 bolts on back.

I’ll be documenting here. I degreased the exterior yesterday, it was a combination of old engine oil, dirt, and undercoating.

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New torque converter maybe? Might as well since its out.

 

[matthewscruiser]

New torque converter maybe? Might as well since its out.

Tempting! I decided to use the current torque converter because I know it worked well when removed from the car. With 120k miles on it, I'm thinking I will run it. It seems like you can't get a "new" converter from Toyota anymore, they are all reman from what I heard--and they are still close to $400!

 

[AARONTLC]

Tempting! I decided to use the current torque converter because I know it worked well when removed from the car. With 120k miles on it, I'm thinking I will run it. It seems like you can't get a "new" converter from Toyota anymore, they are all reman from what I heard--and they are still close to $400!

Ouch! Well then, sounds like a good plan. Hope this goes well for you. I don't have an 80 Series/450 but I sure do appreciate them. Good luck!

 

[OGBeno]

Save money and just clean the filter. It’s metal mesh. It doesn’t go bad or lose its filtering abilities.

 

[matthewscruiser]

Save money and just clean the filter. It’s metal mesh. It doesn’t go bad or lose its filtering abilities.

Thanks Beno! I do recall hearing it’s just a screen now that I think about it.

 

[baldilocks]

I recently had the A343 going into my current build totally rebuilt and we decided to install the TransGo valve body reprogramming kit.

TransGo - Toyota A340, A341, A343 SHIFT KIT® Valve Body Repair Kit

This 340 SHIFT KIT® Valve Body Repair Kit fits 1985 and newer Toyota, Lexus, Isuzu, Mitsubishi, Hyundai, Kia and Jeep vehicles equipped with the A340,

transgo.com

 

[matthewscruiser]

I recently had the A343 going into my current build totally rebuilt and we decided to install the TransGo valve body reprogramming kit.

TransGo - Toyota A340, A341, A343 SHIFT KIT® Valve Body Repair Kit

This 340 SHIFT KIT® Valve Body Repair Kit fits 1985 and newer Toyota, Lexus, Isuzu, Mitsubishi, Hyundai, Kia and Jeep vehicles equipped with the A340,

transgo.com

Interesting, what are the benefits over factory? were you looking for firmer shifting? Is an DIY install very involved?

 

[baldilocks]

Interesting, what are the benefits over factory? were you looking for firmer shifting? Is an DIY install very involved?

My rig is still in pieces so I can’t testify just yet but I came from 93 and 94 models and now my first 80 with the A343 which American shops actually know about and will rebuild. I had the transgo kit installed with the enthusiastic agreement of the shop owner. Jeep used this same trans in many jeep vehicles. I read quite a few threads over the years where 95-97 owners installed the transgo kit. Based on that reading, my trans techs experience, and what TransGo says and the link I posted I felt it a good idea.

I had a TransGo kit installed in my 2005 Dodge/Cummins 48RE several years ago and it made a significant improvement.

The kit is not expensive and not super difficult to install based on what I’ve read about it.

 

[Malleus]

For the OP: install is plug and play.

Not expensive is a reach; the last time I looked (a couple of months ago) they were $1,500 and your valve body for a core. That's like saying a Sniper for a 40 isn't expensive.

I've wanted one of these for my '94's A442F for a long while, but the price keeps me out of the market. If they'd sell a kit, I'd be interested...they have kits for just about every other Aisin transmission.

 

[Malleus]

I have an A343F transmission (120k miles or so) that I will be installing with a new engine next month. (LX450).

I’m planning to do the following:
- Replace output seal (90311-48016)
- Replace input seal (90311-38020)
- Replace shift solenoids (x2 85420-21090 and x1 35250-50030)
- Replace filter (35330-60020)
- check valve body torque
- Increase line pressure from Medium to High position
- Reseal pan with 1281 FIPG
- Reseal rear extension housing with 1281 FIPG
- Replace ATF inlet/outlet union O rings (x2 90301-11006)
- Top off with fresh fluid

Is there anything else I should consider doing? Has anyone removed the rear extension housing to reseal the FIPG? It looks pretty basic, 6 bolts on back.

I’ll be documenting here. I degreased the exterior yesterday, it was a combination of old engine oil, dirt, and undercoating.

View attachment 3757736

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Why are you doing any work on a transmission with 129k miles on it? Everything you listed should be nearly new. Just curious?

If it was me, and I was replacing anything on a transmission that new, it would be the fluid in the cooling circuit. Flush the lines and cooler with kerosene and then backflush with new ATF until it comes out all ATF. It'll take less than a quart of each. I used a cheap electric fuel pump and a couple of feet of plastic tubing when I rebuilt my son's 2000 A343F recently.

I second the torque converter, if it is the original. If it has the same miles on it the transmission does, I wouldn't bother.

 

[matthewscruiser]

Why are you doing any work on a transmission with 129k miles on it? Everything you listed should be nearly new. Just curious?

If it was me, and I was replacing anything on a transmission that new, it would be the fluid in the cooling circuit. Flush the lines and cooler with kerosene and then backflush with new ATF until it comes out all ATF. It'll take less than a quart of each. I used a cheap electric fuel pump and a couple of feet of plastic tubing when I rebuilt my son's 2000 A343F recently.

I second the torque converter, if it is the original. If it has the same miles on it the transmission does, I wouldn't bother.

Because the two seals, FIPG, and O-Rings are far from new at almost 30 years old. The solenoids are a stretch, but that’s my choice. I’m giving it the works while it’s sitting on a bench.

We’re talking about one afternoon of work to make sure I don’t have to pull a leaky transmission out later. Seems reasonable to me.

 

[Malleus]

I wasn't picking at you, just curious.

 

[Malleus]

FWIW, if that transmission really only has 120k miles on it, you should replace the two seals on the transmission shift rod, on either side of the case. These seal the valve body area and will present problem if they spring a leak, being as low as they are. You also need a new collar (Toyota calls is a spaced) on the shaft, where the spring pin goes in. You have to chisel it off to get the shaft out to replace the seals.

I replaced the pin too, but that's just me. I don't trust reused spring pins.

These should all be the Savannah or Atlanta warehouse.

 

[matthewscruiser]

I wasn't picking at you, just curious.

all good, I wasn’t upset, that was just my train of thought!

Thanks for the advice on flushing!

 

[matthewscruiser]

FWIW, if that transmission really only has 120k miles on it, you should replace the two seals on the transmission shift rod, on either side of the case. These seal the valve body area and will present problem if they spring a leak, being as low as they are. You also need a new collar (Toyota calls is a spaced) on the shaft, where the spring pin goes in. You have to chisel it off to get the shaft out to replace the seals.

I’ll check this out!

 

[Malleus]

For some reason, I assumed you meant it had 120k rebuilt miles on it. I wish I could find a 120k original mile transmission.

 

[matthewscruiser]

For some reason, I assumed you meant it had 120k rebuilt miles on it. I wish I could find a 120k original mile transmission.

I got lucky I think. I still think sub-200k is good. I bought it used from a cruiser mechanic that said it shifted great before the part out. The engine ran low on oil and started knocking. Paid $450. It was a birthday present to me last year

 

[Malleus]

Since it's on a bench, you might also consider the two O-rings and the seal on the 2nd coast brake piston:

EDIT: other way around. The O-rings seal the case. Obviously.

These didn't immediately come to mind because the piston is high on the case side and the failure of the O-rings would only cause a shift lag (I think it would eventually catch), but they would all be cheap, all are in the overhaul kit, so it would make sense (at least to me) to get them all done while you're replacing old rubber. And they're all external to the case, so you don't have to break it down.

The business end of the piston rod pushes against the brake band, so there's no adjustment to make when you reinstall it. And, with the pan off, you can stand the case on end and function check everything with shop air. This would let you know the condition of you clutches, too.

The procedures are in the unit repair manual, in the Resources section, if you're interested. The piston will likely be stuck in; I had to encourage it by grabbing the external cross in the casting with a pair of pliers and twisting it out.

 

[baldilocks]

For the OP: install is plug and play.

Not expensive is a reach; the last time I looked (a couple of months ago) they were $1,500 and your valve body for a core. That's like saying a Sniper for a 40 isn't expensive.

I've wanted one of these for my '94's A442F for a long while, but the price keeps me out of the market. If they'd sell a kit, I'd be interested...they have kits for just about every other Aisin transmission.

Are you referring to the TransGo valve body kit? $99 in this eBay ad.

Transgo A340 AW4 Reprogramming Shift Kit A341 A343 Toyota Jeep (SK340-HD2)* | eBay

Fits 1985-on A340, A341, A343, Jeep AW4 4SPD. This 340-HD2 Reprogramming Kit fits 1985 and newer Toyota, Lexus, Isuzu, Mitsubishi, Hyundai, Kia and Jeep vehicles equipped with the A340, A341, A343 and AW4 series automatic transmissions.

www.ebay.com