I think muh transmission is about to poop the bed.

[IronJen]

'99 Suburban K1500, 185,000 miles.

Been noticing just in the last month or so the transmission wants to kick down at the slightest throttle input. Also, going up hills, it seems to drop down sooner and go up slower than it did just a couple months ago. Used to be I could run up Spring Mountain pass and hold 60-65 the whole way and not even kick down. I came back from Vegas today in 2nd gear (because that's all it would do) and barely holding 35mph. I was legit worried it wasn't going to make it either. It felt like it would slip, then grab, then slip, then grab. Did that the whole way up. I was really kicking myself for not taking the long way up through Indian Springs.

On flat ground, it seems to run OK, although it seems to hang in the low gear a long time before the up-shift. And like I said, it will drop down into passing gear in a stiff head wind. It also seems to be worse with temperature. I have noticed the symptoms are more pronounced since it got hot this summer, but correlation does not equal causation. However, I have noticed the symptoms are less pronounced when I first jump in the truck than after it's been running for a couple hours.

I have checked fluid level and that's fine. Any sure fire way to tell if the tranny is about to give up the ghost?

 

[Coup d'etat]

When's the last time you had it serviced? New filter and pan gasket. I use Amsoil synthetic trans fluid when I do a service. It handles high heat very well without breaking down. Vegas heat is not transmission friendly. TBPS determines shift points through the TCU. If the TBPS is dirty or well worn, it can cause erratic shifting.

 

[LASCHRIS]

Pahrump transportation

 

[Harley]

What does the fluid look and smell like?

 

[IronJen]

When's the last time you had it serviced? New filter and pan gasket. I use Amsoil synthetic trans fluid when I do a service. It handles high heat very well without breaking down. Vegas heat is not transmission friendly. TBPS determines shift points through the TCU. If the TBPS is dirty or well worn, it can cause erratic shifting.

I did a filter change a couple years ago. I didn't flush the fluid. I've been told that's actually a bad thing to do with a worn transmission, just replaced what I lost with the filter change. Couple years may sound like a lot of miles but I only drive the truck a few days a week, so two years is probably only 10-15k miles.

 

[IronJen]

What does the fluid look and smell like?

Got back a little late, and I was overheated since the truck doesn't have AC. Will check tomorrow.

 

[Gullwing]

I did a filter change a couple years ago. I didn't flush the fluid. I've been told that's actually a bad thing to do with a worn transmission, just replaced what I lost with the filter change. Couple years may sound like a lot of miles but I only drive the truck a few days a week, so two years is probably only 10-15k miles.

I've seen one or two go our right after a complete flush. When my mom's old car at 200k+ needed a transmission leak fix requiring oil pan drop. I replaced needed part, filter and gasket and used mostly old fluid, topping off as needed. Though didn't keep that car long enough to continue the 1-2 quart changes. So no idea if good idea or not.
But if fluid level is good on yours, filer is installed correct and all that, could be a solenoid or such. Need to have someone who knows that transmission to figure it out.

 

[MET45]

Could be as simple as a vacuum line, and a vacuum line could be the AC problem too. Check the vacuum lines.

 

[Harley]

Forget all this guesswork, its OBD II. Get yourself a scanner that reads transmission codes.

 

[MET45]

Forget all this guesswork, its OBD II. Get yourself a scanner that reads transmission codes.

I just bought this one. Works with my iphone. Well worth it. Between this diagnosing and explaining in plain english, and watching youtube videos, I was able to change my own O2 sensor on my van. Saved $$$. The app is free. Works fine without buying the premium subscription.

https://www.amazon.com/gp/aw/d/B013RIQMEO?psc=1&ref=ppx_pop_mob_b_asin_title

 

[Harley]

I just bought this one. Works with my iphone. Well worth it. Between this diagnosing and explaining in plain english, and watching youtube videos, I was able to change my own O2 sensor on my van. Saved $$$. The app is free. Works fine without buying the premium subscription.

https://www.amazon.com/gp/aw/d/B013RIQMEO?psc=1&ref=ppx_pop_mob_b_asin_title

That one does not support transmission codes. Most of the cheaper ones wont. There might be a couple that Im not aware of but usually anything under $100 or so wont read much more than just the generic codes.

 

[IronJen]

I pulled the dipstick today. Transmission fluid is still pretty red and only a very faint burnt smell. Maybe not as bad as I feared? I do happen to have a pretty decent code reader, but it's a few years old. The Suburban is older. I'll hook it up tomorrow and see if there are any transmission codes.

 

[Marcus2492]

My personal experiences and all the forum readings I’ve done over the years is with those gm/Chevy trans of the era 4l60e or 4l80e is that they take a poop at 200000 miles or slightly above or below. my father loves chevys and all the ones he’s had began to have trans issues at slightly over 200000 miles which varied from slippage to complete loss of gears.

 

[JR3]

Does your truck have a tach? Do the RPMs match what the engine is doing or are the RPMs running high compared to speed?
I just wonder if the trans is slipping or if it could be an engine power issue

 

[tdyoung58]

Back in the day, if a transmission started to slip we'd add a bottle of Dot 3 brake fluid which would prolong the life a while. Not sure how that would work with newer vehicles.

There are a few companies that make additives that claim to help with slipping. I've used Lucas before but it was probably 20 years ago

 

[IronJen]

My personal experiences and all the forum readings I’ve done over the years is with those gm/Chevy trans of the era 4l60e or 4l80e is that they take a poop at 200000 miles or slightly above or below. my father loves chevys and all the ones he’s had began to have trans issues at slightly over 200000 miles which varied from slippage to complete loss of gears.

Doesn't sound unreasonable. I would love for a transmission to last forever, but a 200k life expectancy, I don't think it owes me anything.

The bad thing is just how expensive it is to rebuild these things. I was expecting a rebuild (with me doing the R&R) to run under $1k. I haven't found any rebuilds or remans for under $2200. If that's the best I can find, I'll scrap the truck and find another one. Far too much money for this truck.

 

[IronJen]

Does your truck have a tach? Do the RPMs match what the engine is doing or are the RPMs running high compared to speed?
I just wonder if the trans is slipping or if it could be an engine power issue

Ya, the engine is definitely not the problem. Absolutely certain the problem is the transmission, one way or another. At close to 200k miles, I am expecting to need a rebuild, but I would be thrilled to find it it was just a solenoid or valve body, something simple like that.

 

[IronJen]

Back in the day, if a transmission started to slip we'd add a bottle of Dot 3 brake fluid which would prolong the life a while. Not sure how that would work with newer vehicles.

There are a few companies that make additives that claim to help with slipping. I've used Lucas before but it was probably 20 years ago

Fortunately, this is more of a back-up vehicle. And with Pahrump being pretty flat, I am still driving it, and will continue to drive it until the transmission falls out of it or I replace it. I just won't be able to drive it into Vegas until this resolves.

I thought about some of that snake oil in a can, and may eventually give it a try. But for right now, I'm going to keep shopping for a rebuild, or maybe a salvage yard.

 

[Harley]

Not sure where you’re looking but a rebuilt with warranty is around $1,000

 

[MET45]

seen a few pull out transmissions on offer up. Maybe one can fit. You can set up a search alert too.

Check out this item on OfferUp. https://offerup.co/PtbnltrBVBb