In order to repair 3000gt synchronizers it is good to be informed about the different types that may be found. There are four commonly found synchronizer material types and all four have been available for the Dodge Stealth and 3000GT AWD Turbo and VR4 models.
3000GT brass synchro
A Poor Copy of a Synchronizer
This is a commonly found overseas copy of the original synchros and it made completely out of brass. It is easy to spot because it is very bright. They do not have nearly the friction co-efficent as the oem synchros and our OEM gear codes are not designed to grip very well with them. They are usable on Reverse and possible gears 5/6, but should generally be avoided. They grind almost immediately if used for 3/4. There only advantage is they are very cheap to make and insensitive to fluid types. Do not use if you want a good performing transmission.
They may work in other makes and models with different rotating weights and/or gear designs. They were very typical of early model 4 speed muscle cars, which had closer gear ratios and lighter input shafts than we see in today’s 5 and 6 speed Getrag transmissions.
Fibrous / ATX Style 3000GT Synchronizers
This is an OEM Getrag 3000GT synchronizer from the early model transmissions. It was used on 3,4,5,r on the 91-92 5 speeds and can sometimes be found on 93 models. It has a good coefficent of friction, but was not really designed for the type of oils used in these Getrag transaxles.
Fibrous 3000GT Synchronizer Performance
This synchro would actually perform best with ATX fluids such as Redline D4, which we have run succesfully in Getrags when the best possible cold shifting is desired, but it is slightly thinner fluid than recommend for heavily loaded gears.
3000GT synchros should be replaced during any overhaul. Using a standard 90 weight type gear oil can ruin these synchros and the way they absorb fluid and metal particles make them unsuitable for re-use.
Sintered Bronze VR4 or Stealth Synchro
Great Performing 3000GT Synchronizers
These are another OEM synchro, used on all later model 5 and 6 speed transmissions. They can be identified by their steel/dark yellow colored body and seperately applied hard bronze friction surface. They have nearly the frictional performance of the fibrous synchros, but are much longer wearing, and much less sensitive to fluids.
They perform best with Redline MTL, Pennzoil synchronize fluids, or OEM Mitsubishi fluids. They do not like thicker fluids as they have small oil channels.
3000GT sintered synchro’s cold performance may be worse than the fibrous synchros because the fibrous ones have very large oil channels.
Carbon Fiber Lined Synchros – Pro Carbon by Synchrotech
Carbon 3000GT synchros are a relatively new addition to available synchronizers for our Getrag transmissions. Combing many of the best attributes, better frictional coefficent than sintered bronze and much surface area than the other synchro types.
These synchros also prefer thinner fluids, such as Torco MTF or Pennzoil Synchromesh.
Cold performance has been noted to be slightly worse than sintered bronze, but once warmed up these perform very well. Carbon VR4 Synchros have only been around a short period of time, so their lifespan remains to be seen, but Synchrotech has been around for many years and has a great reputation.