My friend just put a non world class T5 (84 model) in his Firebird and put 10W-40 motor oil in it. Is this better then gear lube ? The tranny has a pretty faint whine in almost all gears but 4 th. Is gear lube reccomended more ? If so... what weight should he use ? Thanx

 

Your friend needs to drain his tranny and put the correct fluid in. All T5's require the use of Dexron II ATF. It is well worth the cost to use synthetic ATF. Mobil 1 or Red Line work very well.

 

i believe only the WC T-5s require ATF anfd the non-WC take gear oil. check your manual to be sure. at any rate use the oil that is suspose to be in it.

 

Mine is a NWC and the B&W T5 service manual states...Due to the tight tolerances held in the T5, Dexron II ATF is the required fluid. Premature synchronizer and blocking ring wear will result if the improper fluid is used.