Can It Get Any More Complicated?
I understand as transmissions progress in time with the future technologies, things will change and probably become more complicated. Let’s look at what used to be a simple design, the park-pawl components found in many transmissions. We have all heard of or seen the new “park-by-wire” systems found on some of the later transmissions in today’s market. The ZF6HP and ZF8HP have their version of park-by-wire with a release cable that can physically pull the park pawl out of the park position if the vehicle were to lose power. That system was probably the first to be seen in most transmission shops.
The Importance of a Positive Seal
Toyota has been plagued by torque converter clutch (TCC) issues for many years. The shudder issues started with the on-off lock strategy and continue with the present-day advanced strategies. Any Toyota 2002 and newer front wheel drive vehicle can have this issue. There are currently two technical service bulletins (TSB) that address this issue.
6L80 Filter Crush
The transmission we are talking about is the 6L80 family of transmissions. It’s quite surprising to know the many times we have encountered this installation error. It is essential that the entire pan be fully supported by a saddle to distribute the pressure evenly across the bottom of the transmission. This will prevent damage to both the pan and filter resulting in immediate failure of your rebuilt transmission.
Jatco/Nissan JF015E (RE0F11A) Vacuum testing
Jatco/Nissan JF015E (RE0F11A) Vacuum testing
K313: A Very Simple Little CVT
Last month we removed the pump from the main case and looked at its unique design. Looking back at the transmission with the pump removed, the forward clutch drum assembly comes into view. The outer lugs on the drum are used to excite the turbine shaft speed sensor. The rpm signal from this sensor can be compared to the engine rpm signal to monitor converter clutch apply. Like a conventional transmission, when the clutch is fully applied, both values should be identical.
Sonnax presents a vacuum test diagram for GM 6T30 and Gen. 2 6T40, 6T45, 6T50.
Sonnax presents a vacuum test dia-gram for GM 6T30 and Gen. 2 6T40, 6T45, 6T50.
Beware of Code P0720: Part 2
When the computer observed an increase in rear prop speed as a result of the axle popping out, it determined the front vehicle speed sensor as being faulty due to it decreasing in rpm. Of course the loss of rpm was due to the loss of power. The computer either didn’t or couldn’t distinguish the difference. Nonetheless, the front vehicle speed sensor was being blamed when nothing was wrong with it or the transmission. Considering the strain this had on the transfer clutch with the axle popping in and out, it explains why they were burnt originally.
Just When I Thought I’ve Seen Everything
OK, let me see if I’ve got this right. The Mercedes 7G-DCT 7-speed dual clutch transmission does not have a reverse idler gear. When shifted to reverse it uses 2nd gear, 3rd gear and 1st along with all four shafts. That’s correct, now let me explain how and why.
Toyota’s K313: Examining hydraulic system
We left off last month having already pulled the valve body from this little Toyota CVT unit. Once the valve body is removed, the 2-wire Hall-Effect turbine-shaft speed sensor (NT) can be seen bolted to the case where it reads the rotation of the forward clutch drum assembly.
1997 ZF Manual Valves
A 1997 Porsche Boxster was towed to a transmission shop. The vehicle was equipped with a ZF5HP19 transmission (Porsche calls this transmission A86.00 Tiptronic) and had 48,408 miles on the odometer. The customer complaint was that the vehicle would drive fine when cold, but the warmer the transmission got, the greater the effort to move the shifter. The shifter would get to a point that it would not move at all. At one point the shifter assembly broke because of the force applied to it.
Replacing Valve Bodies Dos and Don’ts: Part 2
I would like to go over some basic (yet very important) things that need to be done when replacing the valve body. I’ll also touch on some things that need to be done during the initial road test to help ensure everything goes as smoothly as possible.
Programming: A Blessing or a Curse
(Re)programming and tuning do share some similarities but are very different and shouldn’t be mixed up. As told in the previous chapter, the program contains a lot of info including the mapping. This mapping is basically the way the car drives “transmission-wise.” This mapping contains stuff like shift speeds, TCC strategy and speeds, shift firmness and pressures.
