Rpm's too high in 4th gear.....what would cause this?

[Yooformula]

03 Yukon with 5.3l, usually the rpms at 55/60mph is 1700-1800rpms, for whatever reason the last few days its been at 2200rpms. I know its in 4th gear but just seems to be laboring and is revving a bit too high, the mpg isnt the best to begin with and a few more rpm's isnt helping. Not sure if its related but the alt is winding pretty loud and I am getting it swapped tomorrow before it dies. Any thoughts on the high rpms though?

[wrath]

Are you sure it's actually getting to 4th gear? For a stock converter, 400rpm is a lot of slip at that low RPM range. My Dad's 03 Tahoe doesn't engage the torque converter clutch until the transmission fluid reaches operating temperature which can take 10 minutes at 55mph.

[BAD LS1]

When its pretty cold out, often times the converter will not lock for a while. My TBSS, ever since installing an auxillary cooler has done this and its just something i deal with. After about 15 min or less it will lock and work like normal. Also quick blips of the throttle when the engine is surely up to temp will often times coax the pcm into giving the nod to lock the converter.

[Yooformula]

thanks that makes sense as it will slip in once in a while if I mess with the throttle. I did end up needing an alt and idler pulley so at least its quiet again.

[Holeshot]

thanks that makes sense as it will slip in once in a while if I mess with the throttle. I did end up needing an alt and idler pulley so at least its quiet again.

And you didnt contact me about parts again. = FAIL :goof

[Yooformula]

sorry brutha but NOBODY beats MJ rebuilders for alts! plus the owner was cool enough to install it on the spot AND rebuild a seized idler pulley!

[Reverend Cooper]

When its pretty cold out, often times the converter will not lock for a while. My TBSS, ever since installing an auxillary cooler has done this and its just something i deal with. After about 15 min or less it will lock and work like normal. Also quick blips of the throttle when the engine is surely up to temp will often times coax the pcm into giving the nod to lock the converter.

Tom can correct me if Im wrong,but if the thermostat isnt getting the car warm enough it will not let it go to lock up either.On our Toyotas it sets a cel. Dont know about the Foreign cars tho (chebbies)

[BAD LS1]

Tom can correct me if Im wrong,but if the thermostat isnt getting the car warm enough it will not let it go to lock up either.On our Toyotas it sets a cel. Dont know about the Foreign cars tho (chebbies)

Yes a P0128 code for too low of temp, but it has to be below 160F sustained for that to happen. I have a 160 in the truck and it runs about 175-180 most of the time.

[Yooformula]

shit. I have a stock thermo in the truck and it usually sits at 195-200 but lately it drops down to 160-170, might have to swap out the thermostat.

[BAD LS1]

shit. I have a stock thermo in the truck and it usually sits at 195-200 but lately it drops down to 160-170, might have to swap out the thermostat.

Verify that with a scanner, the gauge on teh dash is COLD MED HOT no real accuracy in between.

The t-stat either works or it doesnt, its bypass port size would have to physically have to grow in size or failed safe stuck wide open to do that. But it is pretty cold back home it looks (not in the country right now) so it wouldnt be unusual to be slightly below the 195 stock temp threshold.

[lilws6]

yea my cars been running cooler lately as well so its normal to be a few degrees low while driving.

[GTO RLY?]

Yes a P0128 code for too low of temp, but it has to be below 160F sustained for that to happen. I have a 160 in the truck and it runs about 175-180 most of the time.

My Grand Am threw that code two years ago in winter. A new Tstat fixed that, but it still took forever to warm up in the morning and would lose temp at a stop with the heater on. I ended up covering 2/3 of the radiator in cardboard for winter, it helped a lot.

[Yooformula]

thermostat fixed it. the truck was losing temp while sitting at idle and took forever for the rpms to drop. Now it rides like normal again and the heat is nice and toasty again.

[Reverend Cooper]

Thats cool glad it worked

[GTO RLY?]

I swear automagics are the invention of Satan himself.

[Yooformula]

if you think that, you havent seen my clutches and t-56's over the years...lol

[BAD LS1]

if you think that, you havent seen my clutches and t-56's over the years...lol

Amen to that!:goof

[Yooformula]

lol, Tom you havent even seen my work orders from the dealership! That car has been paid for twice over by the warranty companies by now! My aftermarket warranty company alone paid for a new trans then 2 rebuilds within a MONTH!! For the 2nd rebuild, I gave them most of the parts from D&D performance that I purchased on the side.

[GTO RLY?]

What kind of power were you laying down? Were you just burning through clutches and chipping gears, or were your synchros taking a dump?

[Yooformula]

at the time no more than 325-350rwhp and all of the above and almost all of it due to fucked up hydraulics. But I have busted all of the synchros and gears, cracked the case and tail housing, broken springs on the disc, you name it....I've done it. Lets just say that contrary to popular believe a T56 WILL go into reverse at 100mph!

[Bobby "Big Daddy" Flay]

at the time no more than 325-350rwhp and all of the above and almost all of it due to fucked up hydraulics. But I have busted all of the synchros and gears, cracked the case and tail housing, broken springs on the disc, you name it....I've done it. Lets just say that contrary to popular believe a T56 WILL go into reverse at 100mph!

Joe's done it at 20mph.

[BAD LS1]

Joe's done it at 20mph.

But his also seems to find its way to 4th gear from reverse at about 30 too:3gears:

[GTO RLY?]

at the time no more than 325-350rwhp and all of the above and almost all of it due to fucked up hydraulics. But I have busted all of the synchros and gears, cracked the case and tail housing, broken springs on the disc, you name it....I've done it. Lets just say that contrary to popular believe a T56 WILL go into reverse at 100mph!


Yeah no kidding... I haven't done it myself, but I've had to go from 4th-6th in the GTO because I would miss 5th by entering the reverse gate... you can feel it. They should have put reverse next to 1st. A lot of the guys on the GTO forum I'm on say to replace the slave if you're in there replacing the clutch, and switch to SS lines. I haven't had an issue yet, but it doesn't seem like an uncommon problem.

[Reverend Cooper]

sounds like Deb should drive it as obviously you can't

[Yooformula]

sounds like Deb should drive it as obviously you can't

says the guy that tried to do some beat down runs and crunched gears.:rolf