Sep 262011

Getting to know your Honda Automatic Transmission Introduction…

Honda owners often ask transmission re-builders why they don’t get many kms from there Automatic Transmissions. The simple answers is that it’s probably never had a  Service. Even following

Honda Automatic Transmission

Honda 4 & 5 Speed Automatic Transmission

the Log Book service schedule it is often to late to service as problems start from as low as 40,000kms.

The Transmission

With known failures at very little kms (60,000kms) you would think the transmission is weak in fact the internals are some if not the strongest in front wheel drive configurations. The design is based on a Manual transmission with multiple shafts transferring drive to the Differential. In place of the Syncro’s & Forks there are Clutch Drums which are activated via computer controlled solenoids.

The Problems…

Clutch Plates…
The most common of them all is clutch material blocking internal filters causing shifting problems and loss of drive after short periods of travel. Automatic transmissions require hydraulic oil pressure to operate the pistons which apply the clutch packs to allow drive and gear changes. This oil is sucked up through a filter into the pump and diverted to the correct location to apply the driven gears which is all controlled by the TCM. When the filter blocks with material the pump cant create oil pressure which means your not going anywhere.

The Cause of Faulty Clutch Plates…
Honda transmissions need the correct transmission fluid and also need the fluid changed regularly. These transmissions have a very high internal free spinning speed which means good lubrication is needed. When clutches are not applied the frictions is allowed to spin with an oil slick between it and the steel plate. When the oil is old or not the recommended fluid it can cause the clutch plate material to fly off as it heats up in that pacific area. External oil coolers wont solve this problem as its a pin pointed heat area the overall oil temp stays the same its just the clutch plate that over heats and fails.

The Fix…
Once it starts you cant stop it as the filters are so small it doesn’t take much  to start causing problems. To fix it you need to have the transmission removed and completely stripped down and rebuilt. Then make sure you service every 20,000kms or 12 Months which ever accrues first.

Servicing the Honda Transmissions…

These transmissions only have a drain plug and all main filters are internal and cant be removed without removing the transmission and splitting the main housings. This is why regular servicing is so important and will help prolong the transmissions life. It is also Critical that a Genuine or Recommended Transmission Fluid is used when servicing or Dry filling.

Recommended Fluids… (NOT Recommended for CVT’s )

Honda Automatic Transmission Fluid ATF-Z1 (Up to 2010)
Honda Automatic Transmission Fluid ATF-DW1 (Up to Current)

The following oils carry “Use when out of  Warranty” Warnings. This could be related to Honda not recommending to service the transmission during the Warranty Period. So if a problem arises under warranty and an aftermarket oil has been used it could be blamed. (Our Opinion Only)

Valvoline Maxlife Automatic Transmission Fluid (Selected Models Use Valvoline Lube Guide Here )
Fuchs TITAN ATF 4400 Automatic Transmission Fluid (Meets the Performance Requirement of ATF-Z1)
Castrol Transmax E Automatic Transmission Fluid (Selected Models Use Castrol Lube Guide Here )
Castrol Transmax Multivehicle Automatic Transmission Fluid (Selected Models Use Castrol Lube Guide Here )
Penrite ATF FM5 Automatic Transmission Fluid (Meets the Performance Requirement of ATF-Z1)
Penrite ATF MHP Automatic Transmission Fluid (Meets the Performance Requirement of ATF-Z1)

External Filters or Screens…

External Solenoids…
Although the main filter is internal the External solenoids have filter screens which are either in a moulded reusable rubber seal or pressed into a steel pipe under the solenoid pack. These screens can be cleaned to help shifting problems however 50% of the time they wont make a difference.

External Removable Filters…
Most 5 speed Honda Automatic Transmissions have an extra external filter mounted in the Heat exchanger plumbing on top of the transmission. The complete heat exchanger unit needs to be removed to change this while transmission is still in the vehicle. The labour cost of changing it normally out costs the benefit of changing it but it can be removed and replaced.