Hi all,
I have a 2000 blazer 4wd with 194,000 miles. Recently it has begun to not want to engage in reverse when cold. If you let it run for about 10 minutes, it runs fine. It also has a pulse when going 60mph where the rpms vary between 1,500 and 2,000. This transmission has almost 90,000ish miles and is about the same millage as when my last one died. Checked the fluid and it was foamy. I've tried looking on the internet and searching the boards and I see a lot of mentions of foamy ATF, but what does it mean? Is it the pump sucking in air or what causes it to be foamy? Any help would be appreciated. Looking at selling old crusty and want to know if this is something I should just stick a junk tranny in and sell it, or maybe something to fix.

 

Seriously? No one? What has this forum come to?!

 

Pump sucking air is a possibility. Might be a leaky O ring on the filter, or someone didn't remove the old one. There are two different length filters for the 4L60E: If yours takes the "deep pan" filter, and a "shallow pan" filter was used, the pump will suck air. If the engine coolant looks like a strawberry milkshake, The trans cooler in the radiator sprung a leak.

 

Thanks! Definitely no milk shakes. I have a sneaking suspicion it's the O ring, however, with all the other issues that it's having, I think it's too late to try and save it. Checking on some junk trannies. Hopefully we can find one for cheap so I can sell this truck.

 

Patience is an awesome thing. You gave the post a day before asking what this forum has come to.
We do live a life outside of the forum.

But I second what Chuck said.

 

Just a thot check the cooler return lines too, I've had things like power steering pumps have a pin hole in the return line and with no visible leak will suck air bubbles and foam the fluid

 

Any trouble codes? Is the fluid level correct? Too high a level and the rotating parts can stir up the fluid. Foaming is usually caused by an internal leak, overhaul time.

Delayed engagement into reverse when cold is a sign of age and miles, the seals on the clutch piston are getting hard and drawn up, letting fluid leak by instead of applying the clutches. Warmed up they soften and work better. The delay just gets worse until it quits engaging some day. Low fluid level can cause this too, it expands when warm and rises.

Pulse at speed sounds like the lockup is dropping in and out. You need a scantool attached when it happens to see if the PCM is commanding the lockup on and off, if it is the likely cause is a bad sensor reading, usually the TPS. If the PCM is commanding lockup steady on, then you likely have am internal pressure leak or the converter clutch lining is going.

 

Fluid level is where it is supposed to be. It is in limp mode at the moment as it takes off in a higher gear, so that also may be some of it. We changed the roter and cap to clear up the hesitation we've been having. Replaced the MAS sensor after trouble shooting that was causing some of the problems. Cleared up most of the issues. The pulse came back, it's like it's slipping at cruising speed when you try to accelerate to maintain speed. There is a lot going on with the tranny at the moment. It hasn't shifted great in a few years, so honestly, it wasn't a surprise. Either way, pretty sure it just isn't worth it when we can get a junker for $200ish..which should run better than the one we have. Honestly I haven't been the nicest to this or the last one! ha! Thanks for the answers on the foaminess as I seriously spent like an hour trying to Google it and search the forum. It gets mentioned a lot, but never really explained. It's just our third vehicle/kid carrier and have a minivan already on the way. Hoping to change out the tranny and sell it since it's winter in Michigan and the 4x4 works great! We'd change it out anyway if we were keeping it. Gotta recoup some of the cost of the new (to us) vehicle. Thanks for the help

 

How many miles does she have?From the sounds of it..It would be more cost effective just to have the tranny replaced with another.A transmission can last as long as 15 yrs.if you maintain it.With todays computer controlled transmissions, it`s just best to replace it after a certain amount of miles.Yes you can take a chance on replacing all of the electrical parts, but who`s to say it will cure your problem.Most of the time a transmission will give you a fair warning,in letting you know that there`s a problem.If anytime you have bubbles in your tranny fluid? it usually means there`s an internal problem lurking in the darkness.

 

The 4l60E transmission doesn't take off in a higher gear when it is in failsafe mode, the main thing you would notice if it was in failsafe is jerking shifts from the max line pressure. You likely have a failed shift solenoid.

These use two solenoids to command the 4 gears, both on is 1st, A turns off you get 2nd, both go off you get 3rd, A comes on by itself you get 4th. There is also a 3-2 solenoid that affects the shifting, but usually it's the A or B one causing the problem. If one is dead or stuck off, instead of 1st you get either 2nd or 4th. Since each solenoid needs to be on in 2 different gears, a dead one will be incapable of shifting into 2 gears, first and either 2nd or 4th will be missing.

These fail electrically all the time, and should throw a solenoid circuit error code. If it has that code, you could try changing the solenoids, they are about $15 each. If you can change your own fluid, you can change the solenoids. But with your other issues it sounds like a rebuild or replace is gonna be needed sooner rather than later.