Question on the C4 trans in my 74'. When you first start up the car and put it into drive it takes a minute or two before it clicks in. In only seems to do it when it first starts up when it's cold. I'm going to change the fluid and filter but does this sound familiar to anyone? Happy New Year! Jon
Did you check the fluid level? Also, was fluid added recently that may have been the wrong type? Will it do it only in "D" or will it also do this if you drop it all the way in "L"?
Sounds like dirty filter and fluid. Could be too much clutch pack clearance because of worn disc's. More likely the filter.
I have personally never seen adding the wrong fluid cause any problems. I run dexron III in mine. I personally feel that the old F type fluid is outdated. Just an opinion though.
sounds like the converter is draining back when car sits. takes a minute for fluid to work back thru trans, just like a dry startup after reassmbly. if i remember its a sticking or defective valve maybe in valve body?
When I first began to experience the problem described, it was the pump that was going out. It didn't last long after that and the tranny had to be rebuilt. Hopfully in your case, it will be something simple like a filter, etc. I like Type-F because it shifts quick and hard...
Yep me too! Actually, hi-po trans builders either recommend F or 10 wt hydraulic oil. Even JW Performance wants you to use F. I use it religiously in my powerglides, going on 200 passes now. I pulled it down this winter, inspected, measured....and put it back together. BTW Dexron has a friction modifier in it...which makes the clutches and bands slip some before they fully engage. Same stuff they use in Track-lock rear ends and GM posi units. Lets the clutches slip a little rather than grab. I know it works in mine...it will literally tear up parts because it shifts so hard. Downshifting is out of the question while rolling. Too hard on stuff Several folks have told me that on hot days where trans temps can get pretty high that 10 wt hydraulic oil works better. Never tried it, but might do it someday...I work for a John Deere dealer so hydraulic oil is not in short supply
hey jon if you found your problem let me know cause I got the same with new filter and oil F. And in ad. to this post, when it's very cold near 0 degré celcius the car stop as soon as I put in gear but once hot no problem it run very well. Thanks David
every day car i say dextron.. race car F all the way... thing is can't find the stuff aorund here to often.. but b&m trick shift is the same crap. i'd check fluid level for the hell of it.. but i'd say the trannys gotta come out.
all that has been said can be a problem. Low fluid, worn seal on converter, bad pump also varnish from never changing the fluid can cause the valve body to be sticky when cold. You may also want to try synthetic ATF. When we put it in at the factory (GM Medium duty)the trans warranty is extended.
The reason that type F fluid is recommended is because it has a more detergency and a higher flash-point than other tranny fluids. You can even extend the life of your motor by using 1 qt of type F and 4 qt of 10W30 oil on your next oil change. The detergents help clean the junk that most motor oils leave behind. Transmissions was one of the few classes I stayed awake for.
The engagement delay is a combination of all the above and aggravated by cooler temps. The F fluid was developed in the 60 for these transmissions to match the clutch and band materials used and gain a desired wear rate consistant with engagement smoothness. The later transmission types like the AOD have different band and clutch facing material as well as more moving parts that need additional fluid lube qualities permoting smooth shifting. It is not a step forward to use the later fluids in the early transmissions unless their industry rating has this spec. Doing so can result in more slippage even though not felt. The greatest wear on clutchs and bands occurrs at the beginning of engagement and at releasing when there is greatest amount of slip friction and surface heat generated. At this point, synthetic fluids show the best long term performance due to their higher flash and burn point as long as all other specs for the clutch/band materials are met. Also there is the seal question. The fluid must not attack the seals but still keep them plyable. Cold weather shifting can be a problem even with relitivley new transmissions and in later auto. I have for example, an 02 F150 with an 4r70w. In our cold temps here, the shifting will be delayed until the fluid and valve body temps come up to some min. temp. I added a cooler last fall and this even results in delaying the warm up of the fluid. Letting the engine idle, warming the,engine does not warm the fluid very fast because the fluid in doing min. work at rest until the convertor starts to function to drive the truck or car. So there are a lot of considerations and no one solution to meet all conditions.
