8th gear and 5.38 question

[BearDog]

I put this question on another post, but it got lost with the other topic.

Just installed 5.38 gears.

Truck now hits 8th almost religiously. The only time it doesn't is in two scenarios. One - when accelerating hard-ish up to hwy speed. It will shift normal all the way to 7th, then once at speed it will stay in 7th. I have to manually pick 8th. Two - cruising at hwy speed, it will downshift to pass or pull a particularly tall grade. It will not go back into 8th. It just stays in 7th. In both scenarios, I have left it to change itself for several minutes, but it will not go back into 8th.

Question: Does it need a TCM flash so it can relearn everything?

Sponsored

 

[1550jrit]

I've got 5.38's and 37's. I have not experienced what you are describing as my truck always finds 8th gear with ease. It did not even do what you are describing during my break-in period. There are rare occassions when I'm on a slight incline or driving into a head wind where the transmission prefers 7th gear, but as soon as either of those conditions goes away it drops into 8th. I'd double check the settings in your Tazer if you have one, and also give it some time to relearn the new setup.

 

[BearDog]

I'll go through the Tazer settings again and double check everything. I need to add 1/4" to the tire diameter anyway to bring the mph reading up 1.

 

[BearDog]

Well, went thru the settings and sure enough, still set at a 4.10 ratio. The shop probably didn't do the specific "save" process that the Tazer requires.

Its set properly now. Drive to work tomorrow it'll get tested.

 

[BearDog]

That was it. Shifts perfect now. Damn I love this truck.

 

[Panthers65]

Awesome, My wife has the Tazer on her wrangler and I haven't changed gears in that, but I use the jScan on my gladiator after the 5.13's and there was a transmission "relearn" profess helped my shift points a ton. Definitely worth it.

 

[AstroZombie]

Will it be worth it to relearn teh TCM after uping tire size to 35's?

 

[AstroZombie]

That was it. Shifts perfect now. Damn I love this truck.

LOVE THAT COLOR!!

 

[BearDog]

LOVE THAT COLOR!!

Me too. It was the only color I wanted. I'm a huge Chevy hugger orange fan.

 

[AstroZombie]

Me too. It was the only color I wanted. I'm a huge Chevy hugger orange fan.

I ended up with Snazberry Pearl. Way better in person and really like it now. Don't see many that color here where I live.

 

[SoK66]

I put this question on another post, but it got lost with the other topic.

Just installed 5.38 gears.

Truck now hits 8th almost religiously. The only time it doesn't is in two scenarios. One - when accelerating hard-ish up to hwy speed. It will shift normal all the way to 7th, then once at speed it will stay in 7th. I have to manually pick 8th. Two - cruising at hwy speed, it will downshift to pass or pull a particularly tall grade. It will not go back into 8th. It just stays in 7th. In both scenarios, I have left it to change itself for several minutes, but it will not go back into 8th.

Question: Does it need a TCM flash so it can relearn everything?

If you changed gears and have not flashed the PCM to recognize the change it won’t perform properly. Easy to do with JSCAN.

 

[BearDog]

If you changed gears and have not flashed the PCM to recognize the change it won’t perform properly. Easy to do with JSCAN.

Got it fixed with Tazer. Shop didn't do the specific "reboot - sleep - sleep" that the Tazer needs. Good to go now.

Sponsored