Bought a 2005 Sport V8 with severe R and OD gears slipping, and figured it was a solenoid, valve body circuit clogged, or low trans fluid (procedures listed at bottom of my post). It wasn't any of these reasons, so now I am looking to buy a lower mileage trans from a salvage yard.

I have found plenty of 2005-2007 Tundra's with the same powertrain as my 4Runner (4.7L, 4x4), and was wondering if an A750F trans from a Tundra is a direct swap into my 4Runner.



Items performed to try to fix severe R and OD slippage:
ATF exchange using cooling line (existing level was low, but old fluid did not smell burnt - was brown in color though)
- brought up to temp, left engine running, removed overflow bolt, drained until little stream, reinstalled overflow bolt

Trans R and OD still slipping

Performed pressure test
Idling - D in spec
Idling - D in spec
Stall - D in spec
Stall - R shoots up to in spec range, but steadily drops in pressure pretty quick (indicative of circuit fluid leak)

Dropped valve body from trans
separated valve body and removed all valves for inspection
cleaned valve body (barely dirty)
checked resistance on all solenoids
installed Sonnax B1 Apply Control Plunger Kit
reassembled valve body and reinstalled
refilled ATF and verified level

Trans R and OD still slipping

you could have tried replacing the solenoids. sometimes it will look normal. i replaced my solenoid on my jetta before and it fixed my problem. the issue i had was when it's cold, it does not shift in first gear right away. i had to wait a few seconds before i can move forward. what's your mileage?

210,000 miles

There is no solenoid that handles R and OD only (gears use different solenoid actuations to divert fluid to the correct clutch/brake packs)

The only items that I can see R and OD share without sharing with any other gear is B1

Attached Images

 

looks like you use s1 and sl2 solenoids on first gear and reverse.

1st works fine, though. All gears work fine (1, 2, 3, 4) along with automatic upshifts and downshifts between these 4 gears.

when placed into D, auto upshift from 4 to 5 works, but it acts like neutral (revs increase with no power)

I have Techstream, and all active tests for the solenoids passed, too.

I have also disconnected the transmission wire and performed a manual shifting test (AT-174), which determines whether the trouble occurs in the electrical circuit or is a mechanical problem. I was able to manually shift up/down through the gears, so the issue is mechanical (line pressure stall reading for R shooting up then gradually going down swiftly is telling me there is a leak in the fluid circuit).

hmm, then nothing is wrong with your solenoid or clutch if it shift 1-5 manually and the car moves. if it's in D and it does not move, could be your shift lever electronics detecting it as if you are in neutral. the mechanism might in the shift lever might be the issue.

Hopefully somebody can chime in if an A750F trans from a 2005-2007 4.7L Tundra is a direct replacement for my 2005 4.7L 4Runner's A750F

Only my opinion I'm afraid, but I can't see why not - you're keeping all the computer/ECU modules from the original car so they will all still talk to each other. The mechanicals should be interchangeable...an A750F is an A750F

Over here, there is no such thing as a 4Runner, so I use FJ Cruiser parts. (Not even official Toyota ones! well I suppose the sump/ATF/diff drain plug gaskets count!)

John at IPT would be able to answer this question.

I have all reasons to believe they are 100% interchangeable, but I think he would be able to give a definitive answer.

IPT Performance Transmissions

One thing to check seeing you live in NJ is to check the connection that is on the transmission. The 5 speed sometimes has issues with the connector corroding in areas that salt the roads. See the video below.

Bad Toyota Transmission..Can We Fix It For Free? - YouTube

Thanks for the reply.

I determined that the connection is not as issue by unplugging it and taking it for a drive. This takes all electronic components out of the equation, but it does not go into 1st or 5th gears. Reverse was still non existent.

Searching Google again, and I came across a thread on IH8MUD forum

He took a 4Runner A750F and placed it in a LX470, after he changed out the below items, and installed the transmission, all was well.

Items needing to be swapped:
- shifter linkage (easy)
- rear extension housing (easy)
- output shaft (hard)
- a few sensors since the pinout was different (easy)

Output shaft
In order to replace the output shaft, the trans needs to be gutted (input shaft, retainers, clutches, plates, etc). Patience, self documentation when disassembling, and a good set of c-clip pliers.

I am currently debating whether a $600 savings of a salvage trans from a Tundra/Sequoia is worth the above steps.

4Runner salvage trans with 104k miles in my area = $1100
Tundra/Sequoia trans with about same miles - $500

I bought a transmission in Canada, local to me, for $600 CAD.

Check out car-part.com and keep an eye out. It seems that some wreckers know what they have and are forced to all but give these transmissions away; while others thing they're sitting on solid gold and demand top dollar, not realizing that buyers for them are very few and far between.