A340 Reman vs Rebuilt vs New Valve Body: What to Buy
Your 4Runner, Tacoma, Tundra or Sequoia has a slow engagement into Drive or Reverse, soft or slipping upshifts, or a torque converter clutch code. Someone has told you the Toyota A340 valve body is the problem, and now you have three choices: a new valve body, a remanufactured unit, or rebuilding the one already in the truck. On the A340 family, the right answer depends less on the label and more on two questions: which valve body type you have, and which valves actually wore out. This guide walks through both so you buy the right part once.
Step One: Identify Which A340 Valve Body You Have
The A340 name covers more than one valve body design, and they do not all swap. Gears Magazine describes three broad generations:
- Early units (1985 to about 2000): one shift solenoid at the rear of the valve body, plus a shift solenoid and a lockup solenoid on the side, with a throttle (TV) cable controlling line pressure.
- 2000-later V8 units: Toyota deleted the TV cable, added an SLT (EPC) solenoid for faster pressure control, and moved all solenoids to the side of the valve body.
- 2000-later four- and six-cylinder units: two shift solenoids, a lockup solenoid and a TCC accumulator solenoid.
Gears also notes that on 2005-later units Toyota replaced the on/off lockup solenoid with a modulated SLU solenoid, which allows partial and full converter lockup based on load. That change alone means a valve body from an earlier truck is not a safe guess for a later one.
Sonnax's A340E/F identification guide goes one level deeper for the 2000-later units and identifies them by upper casting ID:
- Type 3, casting ID 8935: V8 applications, EPC-style throttle control only.
- Type 4, casting ID 8938: V6 or V8 applications, EPC or cable-style throttle control.
The Sonnax valve body layout lists the earlier Type 1 bodies by casting codes 8930 and 8931. Write your casting number down before you shop. Every option below, new, reman or repair parts, has to match it.
Step Two: Confirm the Valve Body Is Actually the Problem
Many A340 complaints are not valve body failures. The Transmission Repair Cost Guide's A340E overview lists erratic shifting and loss of forward gears that can come from a failed solenoid or a torque converter issue, overheating from towing and stop-and-go use, and loss of 4th and Reverse tied to the reverse boost valve, channel plate and stripped splines on the 4th gear clutch hub shaft. That last one is a hard-parts failure no valve body will fix.
The same source lists two Toyota bulletins worth checking before you condemn anything:
- TSB TC001-98: a chatter noise when shifting out of Reverse into Park or Neutral, corrected with a revised valve body that adds a check ball.
- TSB TC002-97: delayed Reverse engagement, corrected with a revised B3 brake return spring, B3 piston rings and low coast modulator spring. That is a clutch-side fix, not a valve body swap.
Before buying, pull codes, check fluid level and condition, and drop the pan to look at the debris. Our guide on how to test an A340 valve body before you replace it walks through the checks, and A340 valve body symptoms covers what each complaint usually points to.
The Known Wear Points Inside an A340 Valve Body
Sonnax publishes the wear points for these valve bodies, and they tell you what a reman should have addressed and what a repair needs to fix:
- Boost valve and sleeve (Type 1): Sonnax states the steel OE valve rides in a cast aluminum sleeve and wears it. Once wear is severe, the result is delayed engagement, low line rise, low or high line pressure in Reverse, erratic line pressure, soft upshifts and repeated clutch failure.
- Dual-ratio boost valve (Type 3 and 4): the Sonnax layout ties it to delayed Reverse, delayed Forward, soft upshifts and low pressure.
- Lockup relay valve bore (2000-later Type 3 and 4): Sonnax says a worn bore limits cooler flow and reduces converter pressure, causing converter apply and release concerns, TCC codes, poor lubrication, overheated fluid, and bushing and solenoid failure.
- End plugs (Type 3 and 4): the layout lists soft shifts, low line rise, slips and flares, which Sonnax addresses with an O-ringed end plug kit.
Sonnax recommends vacuum testing the lockup relay circuit. If the port will not hold the minimum reading, or wear is visible, the bore needs service.
The Three Options, Explained
1. Rebuild the valve body you have
This is the only option where you know exactly what you are getting: your original casting, calibrated for your truck. The trade-off is that you are the quality control. On the 2000-later Type 3 and 4 bodies, most of the fixes are drop-in parts, but not all of them are:
- The A340E Sonnax dual-ratio boost valve kit (97741-01K) targets delayed engagement and soft upshifts on Type 3 and 4 bodies.
- The Sonnax O-ringed end plug kit (97741-19K) includes seven end plugs to seal leakage paths behind the valves.
- The oversized lockup relay valve kit (97741-20K) fits 2000-later Type 3 and 4 bodies, but Sonnax lists reaming tool F-97741-TL20 and a VB-FIX fixture as required. Most home mechanics send that step to a shop.
On older Type 1 bodies, measure the OE boost valve before ordering. Sonnax offers two versions (97855-23K for a .566-inch large spool, 97855-30K for a .546-inch large spool) and warns that you must measure to order the right one.
Choose rebuild if: the pan debris is light, codes point to pressure or TCC control rather than hard parts, and you (or a shop) can do careful valve body work.
2. Buy a remanufactured valve body
A proper reman should arrive with the known wear points above already corrected and the bores tested. The value is time: you bolt in a unit someone else has already inspected. The risk is that quality varies from one remanufacturer to the next, and a unit that was only cleaned and resealed still carries the original bore wear.
Before you buy a reman, ask:
- Does it match my casting ID (8935, 8938 or the Type 1 codes) and solenoid layout, including the 2005-later SLU lockup solenoid?
- Were the boost valve, lockup relay valve and end plugs replaced or tested, and was it vacuum tested?
- Are the solenoids new or reused?
- Is a core return required, and what does the warranty cover?
Choose reman if: you want the fastest bolt-in fix and the seller can answer those questions clearly.
3. Buy a new valve body
A new factory valve body resets every bore to zero wear. What it does not do is add any of the aftermarket corrections above; it is built to the original design, including the same valve-in-aluminum wear pattern Sonnax describes. It also has to match your exact generation and casting. The Gears Magazine timeline shows why a new valve body for the wrong year is still the wrong part.
Choose new if: the original casting is damaged (cracked, cross-leaking beyond repair, or stripped), and you can confirm the exact match for your truck.
Replace While You Are In There
- Shift solenoids: if the valve body is out, the A340E shift solenoid kit is easy insurance on a high-mileage unit.
- Lockup solenoid: Sonnax links lockup relay bore wear to solenoid failure. If you have TCC codes, consider the A340E TCC lockup solenoid kit.
- Filter and pan gasket: always, since the pan is already down.
- Fresh fluid: refill to the level and fluid type in your owner's manual.
Browse the full valve body collection or our shift kits if you are correcting line pressure at the same time.
Cost and Effort
All three options share the same basic labor: drain and drop the pan, unplug the solenoids, remove the valve body, and install the replacement. That is a moderate driveway job with the right tools and patience.
- Reman or new: the lowest skill level. It is mostly a remove-and-replace job, but you must match the casting and solenoid layout exactly.
- Rebuild with drop-in kits: more time on the bench and a clean workspace, but no special tools for the boost valve and end plug kits.
- Rebuild with a lockup relay bore repair: needs the reaming tool and fixture, so it is usually a shop job.
For how the numbers compare, see our breakdown of A340 valve body replacement cost and whether it is worth it.
Frequently Asked Questions
Can I put a 2000-later A340E valve body in an older A340 truck?
Not as a simple swap. According to Gears Magazine, 2000-later V8 units dropped the throttle cable and added an SLT (EPC) solenoid, and the solenoid layout moved. Match the casting ID and solenoid layout to your transmission.
Will a new or reman valve body fix delayed Reverse?
Only if the valve body is the cause. The Transmission Repair Cost Guide lists TSB TC002-97, which corrects delayed Reverse with a revised B3 return spring, B3 piston rings and low coast modulator spring. Those are clutch-side parts. Worn boost valves can also cause delayed engagement, so test before you buy.
What is the most important thing to check on a used or reman A340E valve body?
Match the casting ID (8935 or 8938 on 2000-later units, per Sonnax) first. Then confirm the lockup relay valve bore was vacuum tested or repaired, because Sonnax ties wear there to TCC codes, overheated fluid and solenoid failure.