Tranny trouble

[liquify33]

At high 3500-4K rpm my truck feels like it’s hitting the rev limiter. RPMs bounce, truck shudders If I punch it at 40-ish it downshifts then jumps around on the tach.
I can hold 5k rpm fine in Park no issues or odd sounds.
Torque converter? Catalytic converters? Any troubleshooting ideas?
Fluid level is good now and smells/looks OK. Not new but clear with no burnt smell. Drives fine until I hit it hard.

I had some issues previously and was low on fluid. No puddles under car and nothing around the transfer case.

Not 100% on dropping the pan and replacing filter at this point.

 

[Rocket Man]

What do you mean by you “had some issues previously and was low on fluid” ? Also what do you mean by “ not 100% on dropping the pan and replacing the filter at this point” ? It doesn’t take much to damage a trans if it’s low on fluid, and dropping the pan to see what’s in the filter is a pretty cheap diagnosis that I recommend sooner than later.

 

[OR VietVet]

Like Mark is saying. You have to have a base of known time frames and services done and what you are currently experiencing. Basics are fluid level, what happened before, last filter service, been adding fluid?, condition of fluid. Assuming a torque converter or maybe even valve body or cat converter problems, is just that, assumptions. Get a base of what is known and go from there. We used to call that "systems based diagnostics" and for each symptom there were obvious first steps for tracking down the problem. That is why I love to check TSB's first. The diagnostic track has already been done for you by other techs. They would help you save time. Might want to join http://www.alldatadiy.com/ and for a full year for $29.95 you can search to your heart's content for many many write ups that help you and your rig.

 

[liquify33]

@Rocket Man
The previous issue was an occasional hard and/or laggy 2-3 shift. Hot and cold both did it.
ETA: By hard shift I mean “Huh, that felt a little off” not “HOLY $@%# WE ALL GONNA DIE”.
No grinding, always moved in gear and up/down shift good the vast majority of the time.

This started right at New Year’s a couple days after I used 4WD out in a field. No mudding , just didn’t want to get stuck. Maybe coincidence, I use 4W-H twice a year so it stuck out.

Added 1 quart, both bubbles happy on the dipstick (hot fluid, level surface) and most issues went away. @PNW VietVet no idea on last service, I’ve had the truck 1 year and 16k miles.

The high RPM issue was intermittent before (maybe once or twice ever), now constant. I can get it to a reputable shop today for filter and fluid change and hope they will let peek at the pan.

 

[OR VietVet]

Yea, a good debris check in the pan is a great start. Maybe the filter has dropped and fluid pick up is effected.

 

[liquify33]

Yea, a good debris check in the pan is a great start. maybe the filter has dropped and fluid pick up is effected.

Will do. That thought had not crossed my mind!
Might owe ya another beer, we’ll see!

 

[OR VietVet]

Well, if you do owe me a beer, I am stocking up for sure.

 

[liquify33]

Got the fluid and filter changed. There was ALOT of clutch material, likely all original filter and gasket.

The sales guy didn’t even come at me with addon services, they weren’t sure it would even drive.

Drives pretty well but not perfect. 2-3 seems decent at over 4K rpm, 3-4 is better but not quite right at high rpm.

I’m gonna wait another 1500 miles before I do anything to it and see if it survives. And no more drag racing on I-10 for my Hoe

 

[OR VietVet]

Basics first got you back in the ballpark but now you see what was in the pan. Start saving your money.

 

[liquify33]

Basics first got you back in the ballpark but now you see what was in the pan. Start saving your money.

Exactly...that 250 shot of Nitrous won't buy itself!

 

[Rocket Man]

Exactly...that 250 shot of Nitrous won't buy itself!

That would definitely take care of that ailing trans!

 

[liquify33]

That would definitely take care of that ailing trans!

Do you think it’s worth it to include an additive like the Lucas transmission stuff or is that just snake oil and hogwash?

LUCAS LUC10009 Transmission fix, 24. Fluid_Ounces https://www.amazon.com/dp/B000ARTZPO/ref=cm_sw_r_cp_api_i_NbrgEbC0JM251

 

[Rocket Man]

Do you think it’s worth it to include an additive like the Lucas transmission stuff or is that just snake oil and hogwash?

LUCAS LUC10009 Transmission fix, 24. Fluid_Ounces https://www.amazon.com/dp/B000ARTZPO/ref=cm_sw_r_cp_api_i_NbrgEbC0JM251

I mean, it’s worth a try, right? All you can hope for at this point is to make it last awhile longer, it’s definitely on its way out so why not. It’s probably snake oil but it might help get some more miles out of it. I doubt it will hurt. But it’s your call of course. That does have a ton of great reviews though, and Lucas is a good name.

 

[liquify33]

I mean, it’s worth a try, right? All you can hope for at this point is to make it last awhile longer, it’s definitely on its way out so why not. It’s probably snake oil but it might help get some more miles out of it. I doubt it will hurt. But it’s your call of course. That does have a ton of great reviews though, and Lucas is a good name.

It’s not quite that bad. I did less than 20 miles when it was cranky to the filter change. I did see the dirty pan, magnet had about 3/16” of crud. I can tell from the black line on my finger where I poked it.
It’s quite happy shifting under partial gas. Kinda noisy in an emergency interstate gun it or brake slam situation but moves along.

I did 150 leisurely miles today mixed highway and city and never had a burp.

I’ve pondered the Corvette servo and a shift rite kit with all the Sonnax goodies installed before this started. That’s valve body only but now I’m worried about the 3-4 clutch while the TCC valve and accumulator issues still lurk as well.

I’ll try to dig up what scarce service history I have on the truck but I can tell at one point it was used to tow a decent sized boat or camper based on the harness added long ago and locations (Biloxi,MS and Conroe, TX).

The guy at the shop thought a dealer had done the last filter change if it wasn’t original based on the amount of gasket maker he had to grind off.

I’m right at 125K miles on a neglected 4L60 so been waiting on a shoe to drop and it did. Just not sure yet if it was a bunny slipper or a work boot!

 

[Rocket Man]

I hate to tell you but if you had a lot of clutch material like you stated, it’s on borrowed time. The 60 is barely enough tranny for these trucks due to the weight, and one with damaged clutches won’t last long.

 

[liquify33]

... it’s on borrowed time...

The list of things that applies to on this truck is long and distinguished!
There are bits literally held together with duct tape, zip ties, and hose clamps. I keep enough emergency tools and fluids in the back to make AutoZone jealous.
The sad reality is that the longer I can keep it running on pennies, the better quality of life I can help provide for a sick family member.