3rd 4th slip high temps

[duallydmax06]

Hello all, I am working on a 02 lb7 3500 2wd. The truck is bone stock has 235,000 mi. The trans is slipping from 3rd to 4th unless your super easy on it, the temps are getting to 200°f not towing and the fluid looks a little dark. The only code is p1093. The truck seems to drive fine and shift fine until you get on it a little then it slips and stays in 3rd until you let off. Anyone have ideas thanks in advance

 

[JoshH]

P1093 is a low rail pressure code. Low rail pressure can cause shifting problems because the engine isn't able to get to the MPH the TCM wants to see to command the shift. Are you sure the transmission is slipping? If it were, it should throw a P0700 and another code for the gear that is slipping.

 

[Evan@InglewoodTrans]

P0193 is a rail pressure code. What exactly does the transmission do on the 3/4 shift?

On Edit: Josh treed me.

 

[duallydmax06]

Ok that makes sense there is no trans codes, it basically just hesitates in 3rd when your on it more than 25% throttle, less than 25% seems to shift good, where should I start with the p1093? Thanks

 

[Evan@InglewoodTrans]

Do you have a way of monitoring rail pressure?

 

[duallydmax06]

Yup the scanner I am using shows (mpa)? But anyway des Shows 159 and when it hesitates at wot actual drops to 20 until I let off and it shifts. Balance rates are good (newer injectors) and trucks not surging at idle

 

[Evan@InglewoodTrans]

From the sounds of it you have a fueling issue not a trans issue. With that low of rail you will hang shifts like crazy.

 

[duallydmax06]

Yes after driving it some more it's defiantly a frp issue, trans only hesitates when I loose the frp, thanks for your help I'll start looking at the fuel issue

 

[Bonestock]

Fuel filter or fprv would be a ggod place to start.

 

[duallydmax06]

Yup that's where i am gonna start tomorrow.

 

[DAVe3283]

des Shows 159 and when it hesitates at wot actual drops to 20

That is the lowest I have ever heard of rail pressure falling! When was the last time the fuel filter was changed, out of curiosity?

And let us know what the pressures do once you get the new one on.

 

[duallydmax06]

Fuel filter has 17k on it with lots of idle time. I will update with my findings tomorrow.

 

[dmax711]

Fuel filter has 17k on it with lots of idle time. I will update with my findings tomorrow.

Change that ASAP lol

 

[Mike L.]

Fuel filter has 17k on it with lots of idle time. I will update with my findings tomorrow.

Kinda like putting a pillow over your face. Same scenario.

 

[duallydmax06]

Lol yup fuel filter took care of it, frp back where it should be, shifts good, plenty of power. Yeah I was surprised at the 17k I do mine at 5k

 

[JoshH]

:thumb: