4l60e Rebuild and problem

Hey guys

I just rebuilt the 4l60e in my 98 Suburban. I installed the Transgo shift kit and used the master rebuild kit from Dacco and a new torque converter. I also cleaned out the cooler and lines with the can from Dacco and blew them out afterwards with compressed air.

The trans shifted perfectly smooth for about 100 miles and then all of a sudden, 3rd and 4th was gone. It does try to shift to 3rd but just slips completely. I have pulled the pan back off and their is quite a bit of greyish black sediment but does'nt look like enough material for the 3-4 clutches to be burned up enough to totally slip. Also, the fluid is still the correct color and does'nt smell burnt.

All the new clutches went back exactly as the old ones came out and I measured all the clearances like the ATSG manual said to and was all well.

Could the 3-4 pack have burned up that quickly and what could have been the cause?

Reply to
schigara
Loading thread data ...

I hate to ask but, did you use the seal protectors when you installed the pistons in the clutch packs? If not, it is super easy to cut the seals so they hold enough pressure to work for a while before letting go. It is also very easy for a snap ring that is not fully seated to pop out under load. Don't ask how I know!! What you describe say "tear me down".

Lugnut

Reply to
lugnut

Yes, but not because of your clutch pack clearances, but because of a fubared piston seal or sticking shift solenoid/valve. The piston seal is the only likely culprit AFAIC. If you can't get into 3rd because the direct clutch is slipping (which slowly wore away the friction material just like slipping a clutch in a standard trans vehicle) then you will never be able to get into 4th. The rotating assembly created by a functioning direct clutch must remain rotating for the overdrive clutch to generate 4rth gear. So... one problem seems like two.

Check the direct clutch piston for cut, backwards, or otherwise improperly installed seals if you decide to tear this thing down.

Toyota MDT in MO

Reply to
Comboverfish

Thanks for the info.

I went back and read through the manual again and feel so stupid. I neglected to even take those pistons out to put the new seals in! First trans rebuild mistake.

Reply to
schigara

As long as you are going back in, you may want to check the four sealing rings on the input shaft. They should be stretched on with a special cone-shaped tool to avoid damage and overstretching. If you did not change them or did not use the tool then it would be wise to look into it, along with replacing *all* of the piston seals.

If you don't know already, you should soak all of the friction plates in ATF before installing them. Make sure to do so when rebuilding your burned (presumably direct) clutch pack.

Toyota MDT in MO

Reply to
Comboverfish

Since you have to go back into it, make sure you take the converter to a trans shop or parts supplier and have it flushed out. If you can't get it flushed, you should replace it. The burned clutch material sometimes tends to be caught in the converter by centrifugal force as it turns. Not all is caught by the filter or screen. This debris does not make it back to the pan. That is why you found what appears to be a relatively small amount in the pan. You may need a new direct clutch housing, clutch piston and all new steel plates. The plates should be in a master overhaul kit. Again, you will find the seal installation kit to be expensive but cheap compared to the work to go in there. I hope you have a clutch pack compressor. A good universal type should be less than a hundred bucks. The tools are the cost to do it right. The redo is the cost of a short cut. If this is a one time job, you can resell them on Ebay.

Good luck

Lugnut

Reply to
lugnut

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.