4L60E hard 1-2 shift. ?????
Thread Starter
Staging Lane
Joined: Mar 2013
Posts: 67
Likes: 0
From: Mount Gambier, Australia
4L60E hard 1-2 shift. ????? I have LS1, and 4L60E in my 1978 pickup, and it has a very harsh 1-2 shift.
I bought a complete car to do my conversion, but know the trans has been rebuilt at sometime(date written on case), and it has a Sonnax cover on the rhs of trans(not sure of the name of the part) So, I presume it has a shift kit of some sort in the trans. Could any part of that Sonnax gear be causing my problem? Its not in the tune, as I have had that checked, and put back to standard for that vehicle it came out of. The tune man even set the pressures way back for the gears to see what happened, and it was still firm even though the other shifts barely worked.
I have read somewhere that the TPS can cause these issues as well, or do I need to pull the trans, and start again?
I bought a complete car to do my conversion, but know the trans has been rebuilt at sometime(date written on case), and it has a Sonnax cover on the rhs of trans(not sure of the name of the part) So, I presume it has a shift kit of some sort in the trans. Could any part of that Sonnax gear be causing my problem? Its not in the tune, as I have had that checked, and put back to standard for that vehicle it came out of. The tune man even set the pressures way back for the gears to see what happened, and it was still firm even though the other shifts barely worked.
I have read somewhere that the TPS can cause these issues as well, or do I need to pull the trans, and start again?
TECH Resident
Joined: May 2006
Posts: 969
Likes: 119
Depending on what size the 2nd gear feed hole is in the separator plate, the type of 2nd apply servo, what spring and accumulator valve in the valve body, and the spring setup in the 2nd accumulator itself. These all determine the 1-2 shift quality at part throttle and full throttle. Can you get the build sheet for the transmission from the former owner, or talk to who built the transmission? You most likely will have to drop the valve body and separator plate and remove the 2nd and 4th apply servos to see what you have here. Once it is out, the necessary modifications can be done to get the right shift you want.
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
In case it wasn't clear from PBA's description, you DO NOT need to pull the trans to fix the harsh shift. In fact, I would start by only drop the pan (and filter) and removing the three bolts on the round 1-2 accumulator housing. Carefully remove the parts inside, lay then out in order and post a picture of them. That will tell us which shift kit it has.
Also what stall are you running? For example, with a 2400 stall my 1-2 shift was very firm, often chirping the tires with even 20% throttle. However with a 3600 stall I can barely feel the shift.
Also what stall are you running? For example, with a 2400 stall my 1-2 shift was very firm, often chirping the tires with even 20% throttle. However with a 3600 stall I can barely feel the shift.
Thread Starter
Staging Lane
Joined: Mar 2013
Posts: 67
Likes: 0
From: Mount Gambier, Australia
Thanks for the replies. The car was a wreck, and previous owner hadnt had it long, so he wasnt sure on any mods that had been done previous. He didnt think the shift was too bad. Maybe coming from a car it wasnt as noticable.
I am running standard convertor as far as I know. Doesnt feel like a stall.
Am running 4.56 diff if that makes any difference.
When i get a chance, I will pull the pan for a look.
I am running standard convertor as far as I know. Doesnt feel like a stall.
Am running 4.56 diff if that makes any difference.
When i get a chance, I will pull the pan for a look.
