4l60e issue

05 trail blazer. 150k. 3-4 clutches burned up. Trans was rebuilt. 2 weeks later front pump failed. New pump installed. Truck shifts fine, not harsh or firm. Weeks later, pump is failed again. Is at shop being torn down. They will investigate on Monday. What would cause 2 pump failures after rebuild? Original pump was ok and not cause of burnt 3-4 clutches. I assumed that was just a typical GM 150k mile, trans failure? Shop #1 said to change tps since it can cause issues with trans computer control. Blazer is at shop #3. Shop 2 did pump work. Shop 2 is 600miles away. Shop 3 is 1200 miles away. Life is complicated.

Here’s a wild guess

The shops that rebuilt the trans are mixing and matching the wrong parts

The 4L60E trans has had many changes and improvements over the years

I wouldn’t be surprised if you have the wrong combination of parts (early vs late, light duty vs heavy duty, RWD vs 4x4, etc.), you will experience rapid parts failure

Perhaps installing a genuine AC Delco rebuilt trans is the way to go

How are these pumps failing? Is there any signs of debris getting into the vanes? Is the final symptom observed a loss of line pressure?

It sounded like your first rebuilder was quite capable. What do they have to say about these failures? If Shop #3 replaces the pump, take pump #2 to them and have a postmortem done by Shop #1.

About the only reason for a pump to burn up would be fluid starvation. Hopefully the transmission filter was fully seated during the rebuild…
(That may sound benign but I’ve seen it a few times…) :frowning:

Having 3 shops stirring the pot can create a number of problems.

Car died in mpls. We bought it as-is. Rebuilt in mpls. Pump failed in SD. New pump was installed in SD. Now it is in Utah. With bad pump. The SD shop said it is covered by warranty. I have not talked to Utah shop about actual pump failure mode

I am wondering if something is wrong with the torque converter or its fitment to the engine/flex plate. IIRC you had the torque converter replaced with the first overhaul.

Check the runout of the torque converter nose when it is attached to the flex plate. Make sure the torque converter has clearance from the flex plate when the TC is first installed in the pump/front cover. Check that the TC is pulled back to the flex plate on installation of the bolts, i.e. the TC does not imping on the rear cover of the pump. Also make sure the TC centering hub fits correctly in the crankshaft counter bore. Finally check that there is not too much clearance in the crankshaft thrust bearing i.e. the crankshaft cannot move to far rearward.

I think your recurring problem may be with the torque converter.

Karma. I do try to point out issue and cut to the chase for most problems here. I come across as somewhat unfeeling so I do try and settle down. Utah shop does not want to replace pump. They feel pump/TC have issue. They actually want to get used trans and rebuild it. Shop in SD is going to try and intervene.

Shop said trans had to come out to fix issue. So I replaced it with used trans/torque conv. Drives fine now. Did job yesterday. Took it to trans tech so he could scope out system. Fluid temp is fine, tps info is fine. Did say gear range selector is off now. Says “1” on scan tool when trans is shifted to 2 or 3. This range selector switch on side of trans is what came with new, used trans. Old trans/switch is gone. Dash indicator does show 1-2-3-D when shifted manually. Truck drives fine now, no firm or harsh shifts. OD is fine, downshifts are fine, smooth. Am having 2nd shop check it out later today.


Does your vehicle have a shift cable going from the shifter to the range selector switch on the transmission?

If so, it might be adjustable

A few weeks ago, I had to replace a broken shift cable on a GM van. After the repair, I wasn’t able to get the shift indicator to show “1” . . . a simple cable adjustment resolved that problem

Tech said it was reading 1 when shifter was in 1-2-3. But dash indicator said 1-2-3. Shop will do diagnostics for typical shop rate. Gotta pay for their time.