Ford transmission repairs & Jmod

12/15/2025

Here's a valve body for Remington's 95 Lincoln mark 8. 93-95 valve bodies are unique and require a few upgrades to make it perform better.

1. The factory pressure regulator spring is known to be weak and fail over time. install the Sonnax spring for elevated line pressure

2. The early style large reinforcement plates are known to cause pressure leaks, TSB from Ford about this in the mid 90's that talked about installing an updated plate kit that eliminated pressure cross leaks between the reverse and forward clutch circuit https://ww2-secure.justanswer.com/uploads/bkitchener/2009-06-30_033415_trans_slip.pdf

3. The early style shift solenoids are known to get debris stuck in them and cause all sorts of weird shifting issues. There is a TSB from Ford that tells you to replace the solenoid with a new design, but the part number they tell you to use is now obsolete and conveniently superseded to the factory replacement solenoid for 96-97 model transmissions - F6AZ-7G484-A

The Jmod on these valve bodies is a bit different, also. There are some additional holes in the plate that need to be drilled. Because early year model transmission do not have the mechanical diode one way clutch, hole #3 and #6 should not be drilled larger than .125". Hole #8 gets enlarged to .238" and hole #5 is typically not drilled. I made a jig out of an old valve body to mark and drill the holes in the plate. The holes marked by arrows are also drilled. These holes balance the TCC fluid apply circuit and reduce the possibility of torque converter shudder. I also opened up "slot 1" in the valve body gasket. This slot acts as the fluid exhaust for the OD servo. Enlarging the slot allows for a firmer 4-3 down shift.

For this valvebody, I drilled the holes as follows:

Hole 1 - .160"
hole 2 - .081"
hole 3 - .125”
hole 4 - .093”
hole 5 - .093”
hole 6 - .125"
hole 7 - not drilled
hole 8 - .238"
hole 9 & 11 - .125”
hole 10 - .093”
both holes mark with arrows are drilled to .093"

11/29/2025

Here is a transmission from John's 2006 Crown vic police car. I am told it lost all forward gears and the transmission had been removed from the car about a year ago. The transmission was brought to me for a full rebuild.

This the failure I see almost all the time with these transmissions, the factory separator plate is too thin and not reinforced in the area between the forward clutch and direct clutch fluid pressure circuits. The plate eventually dimples from the 2-3 accumulator piston retainer pushing on it, which lifts the plate off the surface and causing a very slight pressure cross leak from the forward clutch circuit to the direct clutch circuit. This small pressure leak allows the forward clutch to slip and over time it wears the clutch material down and increases the space the clutch pack has to travel to apply. Eventually this causes the forward clutch piston to over travel, then cut the outer piston lip seal then the return spring forces the piston back into the drum, which is exactly what we see happening here.

The transmission was full disassembled, cleaned and everything inspected for damage. Aside from the forward clutch damage, I also found the Intermediate one way clutch snap ring was damaged, the OD band was burned and the friction material was starting to pit, the reverse clutches were dark and the friction material was starting to erode or disintegrate and the reverse band was worn.

Going back together with a full rebuild kit, which includes; seals, gaskets, clutches and bands. The one way mechanical diode is upgraded to a later style that has more locking teeth and secured with a new spiral locking ring. Then the fluid feed or***ce in the front pump stator is enlarged to allow more cooled fluid to the one way mechanical diode. The OD band is updated from a tan paper friction material to one with a black high carbon friction material. This material resists heat much better. The valve body is updated with Sonnax shift valves, Superior brand tuff plate and a jmod is done to match required shift firmness the customer requested.

Transmission gets reassembled with a new Ford/motorcraft filter and a Dorman pan with a drain plug. John tells me the transmission was installed a few weeks ago and performs very well.

10/06/2025

John drove up from Louisville for a Jmod on his 2004 DTR Marauder. I built a spare valve body ahead of time. Once the transmission was cool enough to work on, I got busy. Removed the trans pan and drained the fluid. The fluid was a dark red color and had a vanished odor and the yellow bobber was still in the pan. With the original valvebody removed from the case, I let all the old fluid drain out. Installed the new valvebody with Jmod, Sonnax valves and a Tuff plate, torquing all the bolts.
Filled the trans with 10 qts of fresh Mercon V fluid and did a quick check for leaks. Test drive confirmed firm and consistent shifts

09/29/2025

Here is a transmission from Donnie's 2009 F-150. The truck is used to tow a small utility trailer and zero turn mower. I built this transmission 3 yrs ago. Donnie contacted me last week saying it stopped engaging in forward gears. Transmission was removed from the truck and dropped off. Ripped it apart and found the forward clutch drum had separated at the snap ring groove. I hear from the interwebz, the forward drum failing like is rather common, but in 25 yrs of building these transmissions, this is the second one I have seen.
I assembled a good used forward clutch and reassembled the transmission with new seals and gaskets and air checked the assembly... it passed !

09/14/2025

The is John's 86-87 2 door coupe. Its been 351w swapped and running all of sorts of cool tricks, like a late model ECM and coil on plug distributor less ignition system. I built a 4R70W for the car several years ago, starting with a trans core from 2002 F-150 using a small block ford bell-housing. John decided he wanted to add more rear gear. To make the mechanical speedometer read correctly, we had change the speedo drive gear from an 8 tooth to a 7 tooth. On this model transmission the speedometer drive gear is machined into the output shaft and in order to change the output shaft, the entire transmission has to come apart (first part in, last part out. John removed the transmission from the car before I arrived. We tore the transmission completely down, swapped the ring gear and other components onto the new outshaft, installed new metal sealing rings and new Teflon sealing rings and reassembled the transmission new gaskets. reinstalled the transmission and verified proper operation and speedometer readings.

09/07/2025

This is what happens when you tow your Crown vic at highway speeds with out disconnecting the drive shaft. This car was towed on a tow dolly, rear wheels on the ground, transmission in neutral and drive shaft connected. Since the front pump is driven by the engine and not turning, there is no fluid circulating to lubricate and cool everything, the driveshaft is still turning the rear half of the transmission with no lubrication.

I got the transmission as a core and was told it was "burned up"
It got so hot, the rear section was completely welded together. The pump, input shaft, forward drum and reverse drum were also welded together, but did come out of the case. The amount of metal debris was shocking. its at least 1/4" deep in the pan sump. The filter was full of metal too. The case got so hot, the pressed in metal cleats that hold the bands in place, were coming out of the case, 1 for the reverse band was missing, the other for the OD band was almost completely backed out.

I got no usable parts from this core, it all want into the scrap bin.

08/16/2025

Kasper drove down from Chicagoland for some work on his 2010 CrownVic police car. Ownership history indicates this was originally used by the FBI out of the Baltimore area. A beautiful blue with the street appearance group (chrome grill, full wheel covers, plush seats and full carpet)

First project was performing a Jmod on the transmission. To save time, I built a core valve body ahead of time. New Sonnax valves were installed along with new Ford gaskets and a Superior Tuff plate drilled for a Jmod. While I had it apart, we discovered the EPC (pressure control solenoid) was worn and very loose in the bore. I removed the solenoid, confirmed it was worn (you can see the groove in the material near the larger o-ring) replace the EPC with a new Ford part and put everything back together.
We took the original valve body apart and found the factory pressure regulator valve, in the valve body was heavily worn and scuffed.

Second project was servicing the rear differential. Somebody had serviced the diff in the past, heavy amount of silicone on the cover and the fluid was clean and a golden brown. Installed a new Ford motorsport rear diff cover and refilled with 2.5 qts of Ford 75w140 gear oil.

Kasper reports the car drove perfectly on the way home and plans to be getting a tune from Marty next.

02/22/2025

I have 2 fully built valve bodies for sale. These valve bodies are for 93-95 AODE/4R70 transmission. Direct swap for 93-95 Crown vic/grandmarquis/towncar, 94-95 Mustang, F-150, Tbird/cougar/mark8.

Valve bodies are fully rebuilt, Jmod is performed and assembled with OEM ford gaskets, Sonnax pressure regulator valve, increased pressure spring and new reverse boost valve.

The valve body ships to you, fully assembled and ready to install. I will also include an OEM ford updated shift solenoid and an OEM filter to match the style of pan you are using (factory flat pan or later style pan with a hump)

$300 each, this includes shipping with in the 48 states

07/25/2023

07/09/2023

Todd drove up from Kentucky with his 2010 Crown vic police car. He bought the car at auction and had it shipped to his house. The car was retired from Miami and when it arrived on the car carrier, it wouldn't start. I am told after they adjusted the transmission range switch the car would start. Then after a couple of days he realized the car wasn't shifting into overdrive, then also noticed the car was limited on power and the engine would not rev past 4000 rpm.
We went for a test drive and verified both concerns. Hooked up the scan tool and verified no fault codes were set or pending. Then I started looking at live data. First I checked the accelerator pedal voltage and throttle body voltage, all seemed normal. Next I checked the transmission range switch position and found the problem. In any gear selection, the range switch was reporting it was in neutral.
Jacked up the car, installed a good used range switch, then verified with the scan tool the switch was reporting the correct gear selection when the shifter was moved to each setting. Test drive the car and confirmed it shifted into overdrive and the engine would rev freely and full power.

03/26/2023

Billy drove over from St Louis for a Jmod on his 2008 Crown Vic retired police car. The car came from Texas was completely rust free.

The car already had RKE programmed and working, but Billy asked I add the wire to the door module to make the truck pop on the key fob works. While we were waiting for the car to cool off, I pulled the door panel and added the wire to pin 12 and connected it to the purple w/yellow stipe in the door harness. Then we verified the trunk pop on the key fob was working.

Once the car had cooled off, I raised the car, remove the pan and old valvebody and installed a freshly rebuilt valvebody. This new valvebody is assembled with Sonnax shift valves, Tuff plate from Superior and new Ford gaskets. New valve body installed and bolts are properly torqued, I refill with fresh mercon V and we go for a test drive. The shifts are crisp and consistent.