Sleepy Transmission?
 

Hi All,

My transmission seems to fall asleep everytime I try to shift from P or N to any of the forward gears. I takes about 2 seconds after shifting before the forward gears engage. After it goes into gear, it runs perfectly fine. It's just annoying becuse I end up screaching my tires sometimes when I hit the gas before the gears are engaged. I scared the crap out of these two old ladies in the parking lot the other day. The truck has been doing this since I got it about 4 months ago (102k Miles). I changed the transmission filter and fluid as soon as I got the truck but that didn't realy help. The fluid was really dirty (almost black in color) but did not seem to have any metal or foreign particles in it. The truck shifts through all forward gears fine after it gets out of park/neutral. Reverse also works fine.

I described the problem to the guys in the local parts store and they said it might be the torque converter, but I'm not exactly sure if they are correct. Any help would be greatly appreciated.

RE: Sleepy Transmission?
 

I was gonna say torque converter too.... or could be a valve body inside the tranny plugged up.... automatic trannys are like opening up pandora's box far as I'm concerned... I don't much mess with 'em 'cept normal maintenance and maybe a pan gasket and filter...:P they're for SURE something for the experts and even THEN I don't trust too many people... I'd ask around to ALOT of shops in the area for someone that REALLY knows what they're doin'... and if ya hear a particular shop/tech's name over and over.... then that's prolly who I'd have take a look at it.... also.. .does it do this goin' into reverse also??? or only Drive... or Over Drive or 2 or 1?.... post us a little more info...:P

and does it shift hard into 2nd or drive??
if it doesn't shift hard into 2nd or drive... then try this...

let it hookup and drive for a bit
the stop... drop it into park again for a min. then go right back into drive... and does it lag then too or go in fine once it warms up some
and if it doesn't do it goin' into reverse... then what I'd say (and don't quote me on this I am NOT a transmission guy just tryin' to make sense of your symptoms) is that you have a valve body or check ball sticking for your first gear. If it was the torque convertor I'd say it'd do it in forward or reverse seeing as how the torque converter always turns in the same direction and engages at the same RPM so I'd do it in forward and reverse the same...



Good luck and let us know what ya findout...;)

RE: Sleepy Transmission?
 

Start saving your $100.
Dark tranny fluid is never a good sign. The only thing ot make tranny fluid dark is tranny parts. Specifically clutch material.

Make sure your tranny is full of fluid. Check it after driving 20 minutes, park on flat level ground and leave the engine running. Check both sides of the dip stick. Fluid level is somewhere between the two lines. From the add line it takes about 1 pint, which is 1/4 quart. Going over by a pint is no big deal, going over by a quart is. Although it will bleed out of the vent hose on top of the tranny and cause you to panic.

RE: Sleepy Transmission?
 

Thanks for the reply guys.

Aquahallic, the truck goes in reverse fine. It only does this when shifting into the forward gears, regardless of the truck being warm or cold. It shifts smoothly throughout all the gears once it gets out of P or N. I was thinking of the same thing as what you said with regards to the torque converter. I thought that it would do it when shifting to both R and any of the forward gears if it was the TC.

Hanr3, my fluid levels have been right in between the two lines (when warm) after I did the filter and fluid change. When I first got the truck, the water pump and thermostat was going bad and my tranny fluid wasn't getting cooled properly so i found out the hard way about the vent hose :) (my older blazers didn't have such a thing) It's kinda scary seeing a big cloud of smoke coming out of the hood from transmission fluid being purged and dumped into red hot headers! Since I didn't find any debris or visible particles in the fluid, I had thought that the fluid was dark because it was old and also got too hot from the failing water pump and t-stat. But then again I could be totally wrong about this as you mentioned about the clutch material.

Is there any way to clean the valve body or check ball without having to take out the tranny? I have installed a drain plug when I changed the filter and fluid (thanks to you guys) so I have no problems with taking out all the fluid again if necessary. If not, any additives you can recommend that might prevent any further damage from happening?

Also, what is the usual life expectancy for these trannys? I've been getting mixed reports from this forum and others ranging from 60k to 180k, with the newer models dying sooner. My older blazers (91 and 93) had over 160k miles on them with the original tranny without any issues.

RE: Sleepy Transmission?
 

Hello, my 2001 trailblazer does this but only when switching into reverse, it clunks and takes about 2 seconds before its actually in gear, but only when going into reverse. Drive is fine. any ideas why?

thanks

RE: Sleepy Transmission?
 

Tranny fluid is full of detergents. Adding in new fluid helps clean out all the crap. Drain and fill the tranny again. This time check your local autoparts stores for some of that Snake oil in a bottle. There are various products on the market to help auto trannies live long fruitfull lives. Add a pint/quart of the snake oil when you add new fluid.

All 700R4/4L60/4L60e trannies ahve the vent tube on top. Its just that on the later models GM added a hose so you can see it.

Useful life is directly in proportion to how hot the tranny gets. The hotter she normally operates at, the shorter the lifespan. The colder she normally operates at, the longer the lifespan. Like everything else, regular fluid changes will keep fresh lubricants in the tranny, and fresh lubricants will help reduce friction, and thus reduce heat build up. The ideal operating tmpurature is around 175-180 degrees.

RE: Sleepy Transmission?
 

Thanks for the reply. I'll change my tranny fluid and put additives when i change my oil in a few weeks. That makes a lot of sense what you said about operating temperatures and transmision life. All my previous blazers were moslty winter trucks (I live in frigid upstate NY), and I drove my car in the summer. The trucks were operated in colder temperatures and not driven hard or fast due to the conditions. So that may have greatly contributed to the trany running smoothly past 160K miles.

This is the first summer that I am driving a truck around (fixing up my car) and even though the new(er) blazer gets better mileage, she still burns a hefty hole in my pocket every week... I think there's just something not quite right with spending more than double the amount of money a week on gas than you do on food... I still love my blazer though :) I'm sure you all feel my pain in some shape or form... but I digress..

Thanks for the info again guys. I'll keep you posted with any changes/new developments on my trany.

RE: Sleepy Transmission?
 

*offtopic*Blaze, Where in Upstate NY do you live? I'm in the Finger Lakes...*/offtopic*

On the addative thing. I have used Lucas Trans fix with great results, but I do not leave it in there. I pour it in about 3-5k miles before I want to change the trans fluid and let it work it's magic. I then drain the trans (through a trans pan drain plug that I added) and ran it for another 3-5k miles and change the fluid again.

RE: Sleepy Transmission?
 

doesn't that transfix just swell the seals??

RE: Sleepy Transmission?
 

I never leave anything like that in for very long and typically flush it out again after another stint of driving as I stated in my post. I have not used it for slipping problems or things like that, but I used it in both my current vehicles right before their trans service - 50k on the Bonneville and 75k on the Bravada at time of change at which point the transfix was in for about 3k for each.

What drew me to it was a mechanic friend suggested that I use it on my old Ram. When the truck would sit for more than a day, it would take a long time for the transmission to engage in any gear. The thought was that the check valve that holds the torque converter full was not seating properly, allowing the TC to drain out, causing the delay. After only 3k with that stuff in there, the problem was gone completely. I just talked with the current owner a few weeks ago and the truck now has 150k miles on it (75k was when I added the transfix and 78k was when I drained it out twice) and the truck is still running great, trans and all.

I guess what I'm trying to say is that if it swells the seals, it doesn't do it to the point of destroying them. Now I wouldn't leave this stuff in permanent like, that may lead to problems, but for me, it has never caused an issue.