Newish transmission not working right.

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Fireball5657

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To start things off, I have a stock TBI 350 and a completely rebuilt 20K miles ago 4L60E, the truck is a 4WD and I have plenty of trans cooling, both the trans cooler built into the radiator and a separate auxiliary trans cooler are on the truck. I don’t tow, and I don’t beat on the truck, it’s mostly just a daily driver.

Now to the issues, I’ve had a hard 1-2 shift since the trans was rebuilt, and it’s never liked winter too much. Now it’s 3 years since the rebuild and it’s gotten to the point where I’m saving money for what I believe to be an inevitable trans failure. It’s hard to describe what the truck is doing but I’ll try my best.

When the engine and trans are cold, the truck is at a complete stop, in drive, completely still, then you begin to accelerate, the engine spins up a bit, truck has a delay to actually moving, then it somewhat lightly slams into gear and it begins to move like normal. Most other cars I’ve driven, even older automatics, the second you hit the gas, it moves forward, but this one has a delay before it moves.

Things change after about 10 miles in the 95 degree Oklahoma heat, when at a complete stop, in drive, then you hit the gas, the truck does the same thing as before, but now once the trans finally “catches”, it feels like it only partially catches, the transmission heavily resists the movement of the engine. The engine wants to rev, but the trans won’t let it, and the engine gets bogged down until a few seconds later when the trans finally feels like going and it catches all the way and the engine roars up and drives normally.

After you get it off the line, it works great and shifts like it should, this is the only issue with the trans, and I have no idea what it is. Fluid is mostly red, smells a little burnt, but not bad, it doesn’t leak, and the engine runs pretty well.

Any help is massively appreciated, i don’t even know where to start, I have no experience with transmissions.
 

stutaeng

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Don't worry, there are plenty of knowledgeable folks here on this site.

Basic question: who did the rebuild and why wasn't it brought back immediately when you noticed the first time?

Was it a, "I bought the truck and previous owner had it rebuilt" type of thing?

The "catching" description I think fits perfectly as a slippage. Have you dropped the pan to look at the fluid? If it's slipping, chances are high that the pan will have a lot of friction material in it. Maybe that's not the case.

I think that's the first step.
 

Erik the Awful

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Having to rev to get moving makes me think the fluid level is low. Are you checking the fluid with the engine running? Either way, I'd try adding a quarter of a quart bottle to see if it helps.
 

Erin

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I had the same symptoms as you with mine, except mine had overheated before the problems started. I brought it to a transmission guy, he replaced the torque converter, and said it was good to go. Symptoms were still there. Then they tried to blame it on the engine. Long story short, I ordered another transmission and haven’t been back to those Joe jacks since.
 

Frank Enstein

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Change the fluid and filter paying extra attention to the o ring on the filter and how the filter fits vs the pan.

A compromised o ring and/or the wrong filter can let the pump suck air leading to burnt clutches and the symptoms you describe.

Use a name brand filter and fluid like a Wix filter and Valvoline fluid (or your favorite national brands).

Look at the deposits in the pan as was mentioned. If the fluid smells burnt or if there are excessive deposits in the pan, it may need a rebuild.

I have had really good results with Justice Brother's (JB) Automatic Transmission Conditioner. It's really good stuff but super hard to find.
 

Fireball5657

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Don't worry, there are plenty of knowledgeable folks here on this site.

Basic question: who did the rebuild and why wasn't it brought back immediately when you noticed the first time?

Was it a, "I bought the truck and previous owner had it rebuilt" type of thing?

The "catching" description I think fits perfectly as a slippage. Have you dropped the pan to look at the fluid? If it's slipping, chances are high that the pan will have a lot of friction material in it. Maybe that's not the case.

I think that's the first step.
Truck has been in the family since new, I was the one that took the old and broken trans out and put the new one in back in 2018. Anyways, the "transmission shop" that rebuilt the trans on my truck isn't around anymore. He was a retired transmission mechanic and family friend who passed away in 2019 thanks to a drunk driver.

The really bad catching and the resistance stuff started right before I got my front suspension completely rebuilt a few weeks ago. The previous transmission that was in the truck before had a slight delay and a clunk before it accelerated too, but it was never this bad.

As far as the fluid goes, the filter and fluid was serviced 11K miles ago, it will get replaced again soon, but I'd be surprised if that was the issue.
Having to rev to get moving makes me think the fluid level is low. Are you checking the fluid with the engine running? Either way, I'd try adding a quarter of a quart bottle to see if it helps.
Yup, still have the original owners manual and I do every step it tells me to. It doesn't leak and fluid level is right in the good zone. I'll stop by an O'Reilly later and get a quart, shouldn't hurt it any.
If the fluid level is correct it sounds like the TQ is not operating properly.
I had a feeling about this, if the filter and fluid change don't fix it, a new torque converter might be my next step. I'll probably also do the RMS while I'm there, my truck marks it's spot pretty bad when I park it.
I had the same symptoms as you with mine, except mine had overheated before the problems started. I brought it to a transmission guy, he replaced the torque converter, and said it was good to go. Symptoms were still there. Then they tried to blame it on the engine. Long story short, I ordered another transmission and haven’t been back to those Joe jacks since.
So the fix for you was to replace the whole thing? Ouch.
Change the fluid and filter paying extra attention to the o ring on the filter and how the filter fits vs the pan.

A compromised o ring and/or the wrong filter can let the pump suck air leading to burnt clutches and the symptoms you describe.

Use a name brand filter and fluid like a Wix filter and Valvoline fluid (or your favorite national brands).

Look at the deposits in the pan as was mentioned. If the fluid smells burnt or if there are excessive deposits in the pan, it may need a rebuild.

I have had really good results with Justice Brother's (JB) Automatic Transmission Conditioner. It's really good stuff but super hard to find.
Good stuff to know. Would a burnt up torque converter cause any sludge or deposits during the filter change, or is that only for the inside of the trans?
 

thinger2

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Truck has been in the family since new, I was the one that took the old and broken trans out and put the new one in back in 2018. Anyways, the "transmission shop" that rebuilt the trans on my truck isn't around anymore. He was a retired transmission mechanic and family friend who passed away in 2019 thanks to a drunk driver.

The really bad catching and the resistance stuff started right before I got my front suspension completely rebuilt a few weeks ago. The previous transmission that was in the truck before had a slight delay and a clunk before it accelerated too, but it was never this bad.

As far as the fluid goes, the filter and fluid was serviced 11K miles ago, it will get replaced again soon, but I'd be surprised if that was the issue.

Yup, still have the original owners manual and I do every step it tells me to. It doesn't leak and fluid level is right in the good zone. I'll stop by an O'Reilly later and get a quart, shouldn't hurt it any.

I had a feeling about this, if the filter and fluid change don't fix it, a new torque converter might be my next step. I'll probably also do the RMS while I'm there, my truck marks it's spot pretty bad when I park it.

So the fix for you was to replace the whole thing? Ouch.

Good stuff to know. Would a burnt up torque converter cause any sludge or deposits during the filter change, or is that only for the inside of the trans?
There really isnt any good "slightly burnt" transmission fluid.
That stink and dark color is metal getting shredded from other metal and the stink is from heat cooking the fluid.
In other words, you have metal on metal contact.
Oil and trans fluid and hydraulic fluid etc are used to provide a "cushion" between moving metal parts in order to keep those parts from contacting each other and grinding themselves apart.
That is "oil pressure" in a basic form.
When those moving parts touch each other, that ground up metal turns into a paste and gets pumped throughout the system and causes more destruction as it goes through the previously good surfaces.
Instead of pumping clean oil or hydro fluid, you are now pumping a metalic grinding paste.
Which just aint good.
 
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