1994 full size Blazer 4L60-e issues

[stutaeng]

I appreciate everyone's help in this matter.

Today I replaced the 180 degree thermostat with a 195 degree t-stat and new gasket. Added one bottle of Dura-Lube synthetic ATF protectant (red 10 oz. bottle) and took the vehicle for a 25 mile drive. The shudder issue is still present, and eventually noticed the transmission does not slam into 2nd, 3rd or 4th gear as badly. The shudder is definitely from the torque converter slipping. I tapped the brakes as it was happening and it stops immediately. I also noticed a rise of between 200-400 RPM during a shudder.

I'll keep driving this vehicle and hope the magic fluid will do something. I'll report back after I drive a few more miles.

Alignment shop says I need a rag joint, and the rest of the steering/suspension is great. The vehicle doesn't tire or suspension vibrate at all with 33" tires all the way up to 75 MPH.

My next step is to replace the transmission mount. I will also drain the ATF with the engine running via the trans cooler, drop the pan and inspect (The transmission is the original and has 268K miles, may have been overheated, and some plastic parts may have become brittle and are not controlling pressure. I also fear the torque converter clutch may have had enough and is worn out, along with the valve body components.), change the transmission filter, do a running flush with the cheap Dexron, and fill to the proper level long with a single tube of the Dura-Lube shudder fix.

Can anyone confirm the use of pulse width modulation for the TCC in a 1993 or 1994 4L60e?

Thanks!!!

This source says no PWM for '93-'94 models: https://www.gmt400.com/threads/the-real-differences-in-700r4-4l60-4l60e-transmissions-by-year.26587/

I think you are in the right direction with the fluid change. But considering the age of the transmission (28 years old!?), the high mileage and the problems you are reporting, I wouldn't hold my breath as far finding a easy fix.

The seals inside the transmissions get hard/brittle and cause fluid loss within the hydraulic circuits, causing pistons and drums to not apply correctly and burnt up clutches. I would strongly suggest you start looking at a rebuild. Get a good shop to freshen it up, and do the valve body valve upgrades and install a new torque or remanufactured converter.

 

[BlazinBlazer1994]

You need the C3500(HD?) steering shaft, that has a U-joint instead of a rag joint at the bottom. That and the longer bottom bolt that goes with the shaft.

Part numbers are in the sticky "Jeep steering shaft" thread. This shaft / bolt is way better than the Jeep shaft, it fits perfectly and is a Genuine GM part.

Awesome!

I do thank you for that information. It is extremely appreciated!!!

 

[BlazinBlazer1994]

This source says no PWM for '93-'94 models: https://www.gmt400.com/threads/the-real-differences-in-700r4-4l60-4l60e-transmissions-by-year.26587/

I think you are in the right direction with the fluid change. But considering the age of the transmission (28 years old!?), the high mileage and the problems you are reporting, I wouldn't hold my breath as far finding a easy fix.

The seals inside the transmissions get hard/brittle and cause fluid loss within the hydraulic circuits, causing pistons and drums to not apply correctly and burnt up clutches. I would strongly suggest you start looking at a rebuild. Get a good shop to freshen it up, and do the valve body valve upgrades and install a new torque or remanufactured converter.

Thank you for that insight.

I'm guessing the same thing with how this transmission operates. If the final fluid swap and additive plus filter do nothing, it is getting rebuilt with a new torque converter.

Not sure if anyone has seen the Precision Transmission videos on YouTube, but that guy is impressive with his knowledge on 4L60e transmissions as well as many others. If I was sure my vehicle would make it to Amarillo Texas from the Salt Lake area, I'd rent a hotel room there and have him do the work.

https://www.youtube.com/channel/UCYAAY7V9ifGS7Q8S35EFVnw

 

[BlazinBlazer1994]

To follow up, I had the transmission rebuilt by a local individual. Lots of upgraded parts. Some springs were broken in an accumulator, which explained the slam shifts. Quick fix with a replacement TCC solenoid fixed the TCC shudder. I opted for upgraded everything and pin-less accumulator pistons, and a wide band. Upgraded trans cooler, plumbed in line with the tank transmission cooler. Upgraded the TC with a nice billet unit. It shifts great and holds in gear very nicely. I'd like to thank the responders to this thread for their knowledge.

 

[Schurkey]

Upgraded trans cooler, plumbed in line with the tank transmission cooler.

Before, or after the rad-tank cooler?

"I" would want it before the rad-tank cooler, so the rad tank cooler warms/cools it to ideal operating temperature before it goes into the trans.

Upgraded the TC with a nice billet unit.

A billet torque converter???

 

[BlazinBlazer1994]

Before, or after the rad-tank cooler?

"I" would want it before the rad-tank cooler, so the rad tank cooler warms/cools it to ideal operating temperature before it goes into the trans.


A billet torque converter???

Yes, I know, a billet TC. It only makes 200hp, and that was in 1994. I may upgrade to a more built 5.7L and I thought that would be a decent upgrade. Wasn't a lot more money.

He's the trans expert, and although I am not sure how he plumbed the cooler, it's in series with the radiator tank cooler. He said the tank cooler should always be used along with a separate cooler, just to be able to handle towing a lot better.

 

[Schurkey]

Yes, I know, a billet TC. It only makes 200hp, and that was in 1994. I may upgrade to a more built 5.7L and I thought that would be a decent upgrade. Wasn't a lot more money.

I have NO idea how someone can sell a "billet" torque converter.

The housing is stamped steel, welded together.

Most of the guts are furnace-brazed, stamped sheetmetal.

Who made this "billet" converter, and what is the part number?

He's the trans expert, and although I am not sure how he plumbed the cooler, it's in series with the radiator tank cooler.

Ask him if it's ahead of the rad-tank cooler, or after the rad-tank cooler.

The alternative is that it's in parallel with the rad cooler, but almost no one plumbs them that way. Virtually everyone plumbs them in series.

 

[BlazinBlazer1994]

Quick image search for 4L60e billet torque converter; see photo attached

 

[Schurkey]

Ah. A more-or-less normal torque converter of small size, coupled to a machined adapter that bolts to a larger-bolt-circle flexplate typical of a V-8.

A really-expensive way of making a small-diameter torque converter fit.

I'd be surprised if that converter had a stall speed suitable for a low-power V8.

 

[stutaeng]

I used to watch the Precision Transmission YT channel and the guy sometimes mentioned a "billet converter." Come to think about it, I never really understood what that meant...

It sounds like it's one of those "upgrades" now that I think about...billet = cool... no matter how you look at it. enough said!

It's good OP chimed in. I love it when guys remember they created a thread and give us an update. Kudos to OP!

Ah. A more-or-less normal torque converter of small size, coupled to a machined adapter that bolts to a larger-bolt-circle flexplate typical of a V-8.

A really-expensive way of making a small-diameter torque converter fit.

I'd be surprised if that converter had a stall speed suitable for a low-power V8.