Houdini

iTrader: (2)

I recently installed a built transmission in my daily driver (1997 Yukon 2-dr) and would like some opinions on my problem before I call up the company who built the transmission... is a sponser here.

Here is the rundown:

The Yukon is (or was) bone stock at the time of the transmission install and had 165,000 miles on the odo.

I had the transmission installed at my trusted shop and everything went without a hitch. I noticed a hard 1st - 2nd shift and clunking when shifting into Drive or Reverse, but figured it was drivetrain slop due to my worn u-joints and just about ready to grenade 10-bolt out back.

*added* 1st to 2nd shift is foolishly hard, feels like someone rearended me slightly.

I assumed the higher stall converter (2500'ish) that I ordered with the transmission just amplified my poor condition rear-end.

The following week I picked up a 14-bolt semi-floater rear and made the swap, figuring I would be killing two birds with one stone... get a rock solid drivetrain and eliminate the hard shift and "clunk" into Drive/Reverse.

Well... the problem never went away and for the past few weeks I've been running down the things that could cause my transmission issue.

1) replaced TPS sensor
2) cleaned MAF
3) checked for proper fluid level
4) verified TPS voltage and MAF with scanner
5) check all grounds on the truck


Nothing has helped in the least bit and I've run out of ideas as to what could be causing this.

I would like to know I've tried everything before I make a phone call to the company and try to work it out with them... cause I got a funny feeling its a transmission build issue.

Thanks

my1994z28

iTrader: (3)

The hard 1-2 shift could be that they installed a shift kit,the clunking sound could be a bad trans mount or motor mount.

Jays_SSZ28

iTrader: (2)

so...is it a 4L60E or 4L80E?

Houdini

iTrader: (2)

Sorry... it's a 4L60E and the transmission mount was checked, forgot to add that to the list of things gone over.

Considering the fairly cheap cost of a transmission mount, I might just throw a new one in this week to give me peace of mind. Going to be doing a oil change anyways... so while i'm under there and all.

Jays_SSZ28

iTrader: (2)

The clunk into drive and reverse could be a high idle, or the case saver performabuilt uses, maybe both.
A hard 1-2 is most likely the accumulator set up and can be changed easy by dropping the pan and three bolts holding the accumulator cover on.
If the other shifts are ok, and not too firm, I'd look into the 1-2 accumulator. Thats a start.

Houdini

iTrader: (2)

Thanks Jay!

The idle has not changed from the previous transmission, thats not to say that it couldn't have been high to begin with when I bought it 6 yrs ago.

I don't really want to start digging into the transmission (even if it means just dropping the pan) other than basic fluid/filter change. I'd like to call the builder and have the transmission unmolested by me.

Oh... I never said it was a Performabuilt tranny. Don't feel the need to drag names into it if it's just a stupid little issue.

Just dredging the knowledge of the forum for things I may have over looked.

Houdini

iTrader: (2)

1st to 2nd is a foolishly hard shift, sound like I'm going to snap u-joints. 2nd

Detroit Gearbox

Servo/valve body acc spring/accumulator combinations. Make sure it doesn't have one of those Superior gigantic super servos.

performabuilt

iTrader: (25)

Depending on what build it is the shift characteristic may be normal. For instance our level 2 and 3 would be rather agressive , The heavy hauler and rocks crawlers units not as much but still with even the covette servo and the wide band theres a lot more there to grab into than stock. In anycase any performance trans will be rather harsh compared to the stock trans. One thing all performance builders use at least the corvette servo if the shift is to agreesive you could always swap the stock servo from your old unit which should soften the shift some. Reguardless of who built it since i have no idea wether its one of ours or not if you like give me a call and i will give you some ideas on ways to address it if you are not happy wit the shift feel. Also note if any tuning has been done to raise line or firm up shifts it would need to be set back to stock with the trans also again reguardless of who built it.