4l70E issue-need help
Thread Starter
Teching In
Joined: Jan 2002
Posts: 29
Likes: 0
From: New Jersey
4l70E issue-need help I had a front pump failure on a 4L70e level 4.5 trans. Builder replaced front pump and said he went thru trans everything else was good. Builder also replaced converter with new TCI single clutch billet 10.5. I had my shop install trans. Let truck warm up and drove down street and trans was slipping in all gears. Got back to shop and checked fluid level-all good. Called builder he said to add another quarts (13 quarts now). Mechanic took for a ride same issue. Builder asked me if I flushed lines and cooler, I thought no because I never told shop to do so. But turns out shop did flush everything, as soon as he removed trans initially, he said he always does that after trans goes bad. So now I know trans was not repaired properly. So now I have to decide do I let this expensive transmission be inspected by a local trans shop or lose another month or more by sending it to a reputable performance trans shop ( like PRM ).
Last edited by Mark B; Jun 7, 2021 at 08:48 AM.
TECH Junkie
Joined: Jun 2008
Posts: 3,204
Likes: 1,391
From: Nitro Alley
First I would like to know what was wrong with the Pump the first time...
Did the Rings or Rotor break?
Did the Transmission have both "Complete" Pump halves replaced?
Yes the Cooler System should always be flushed or replaced.
What is wrong/ broken with this Pump?
It is possible for the Transmission to be damaged from not flushing the Cooler System... Yes it is.
However it may not be the case here.
At this point several measurements should be taken...
Ensure that Flex-Plate fitment, Crankshaft Pilot fitment, Torque-Converter fitment, and Transmission to Engine fitment are all correct.
A misalignment, incorrect spacing, pulling the Transmission on to the engine with the Bolts, and several other things can damage the Pump when installed.
Also make certain that the Pump Assembly has been "Blue-Printed".
I see that you are in NJ... how long is the drive for you to the Upper West-Side?
Did the Rings or Rotor break?
Did the Transmission have both "Complete" Pump halves replaced?
Yes the Cooler System should always be flushed or replaced.
What is wrong/ broken with this Pump?
It is possible for the Transmission to be damaged from not flushing the Cooler System... Yes it is.
However it may not be the case here.
At this point several measurements should be taken...
Ensure that Flex-Plate fitment, Crankshaft Pilot fitment, Torque-Converter fitment, and Transmission to Engine fitment are all correct.
A misalignment, incorrect spacing, pulling the Transmission on to the engine with the Bolts, and several other things can damage the Pump when installed.
Also make certain that the Pump Assembly has been "Blue-Printed".
I see that you are in NJ... how long is the drive for you to the Upper West-Side?
Thread Starter
Teching In
Joined: Jan 2002
Posts: 29
Likes: 0
From: New Jersey
By West Side are you NYC? I am in South Jersey.
The first time I was driving along at 40 mph regular acceleration to get 50 mph, when truck felt like it went into neutral, I coasted to a stop. Turned off truck, looked underneath but did not see any visible damage. I restarted it, heard noise from front of trans. That increased with rpm. Shut off and towed to shop.
As per installer convertor was shimmed 1/8
The first time I was driving along at 40 mph regular acceleration to get 50 mph, when truck felt like it went into neutral, I coasted to a stop. Turned off truck, looked underneath but did not see any visible damage. I restarted it, heard noise from front of trans. That increased with rpm. Shut off and towed to shop.
As per installer convertor was shimmed 1/8
Last edited by Mark B; Jun 7, 2021 at 08:48 AM.
