Newish transmission not working right.

[Frank Enstein]

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?

If the torque converter clutch is worn it can deposit clutch material into the pan. It wouldn't be a bad idea to flush the cooler lines or at least blow them out with air.

 

[alpinecrick]

Wellllllll, this is my big chance to say it......

Keeping the fluid BRIGHT RED is the best thing a guy can do for the trans. Not red, not dark red, not brown, not black. A trans pan with a drain plug, and draining the ATF that's in the pan every 5K-10K will go a long ways towards a long lived auto trans.

If the fluid in your trans was ever dark red, it's been burned, and that's not good for the trans or TQ.

 

[Boostvalve67]

so is there any kind of noise when the engine revs up before the catch? does it make any difference if the trans is in low range on take off hot or cold? also check if it makes any difference if its in 4wd high. I have seen the snap ring come off the output shaft in the transfer case that locates the shaft to the rear bearing. on take off the shaft and rear assembly moves front and back in the t case and will come disconnected from the input shaft momentarily. in 4wd it did not. I don't remember the model number of the case but it has a small output housing bolted to the rear half of the case. the snap ring is just under the housing locating the shaft from moving front to back.

 

[SUBURBAN5]

Wellllllll, this is my big chance to say it......

Keeping the fluid BRIGHT RED is the best thing a guy can do for the trans. Not red, not dark red, not brown, not black. A trans pan with a drain plug, and draining the ATF that's in the pan every 5K-10K will go a long ways towards a long lived auto trans.

If the fluid in your trans was ever dark red, it's been burned, and that's not good for the trans or TQ.

So what about metallic bright red lol. Jk


I like your idea of installing a pan with drain plug. Ever use rock auto skp? I'm thinking of servicing my trans but cant tell which pan I have.. I believe its deep?

 

[alpinecrick]

So what about metallic bright red lol. Jk


I like your idea of installing a pan with drain plug. Ever use rock auto skp? I'm thinking of servicing my trans but cant tell which pan I have.. I believe its deep?

Metallic Bright Red might be a little skeery…….

Measure your pan depth. Officially a shallow Pan is 2 3/8”, the deep is 3 1/8”.
I use the CFR Performance EDP painted pans. The deep Pan looks to be 1/8”-1/4” deeper than GM’s deep Pan, and does not have the “step down that the factory deep pans do. The CFR deep pans hold a lot of ATF.

 

[SportsterSam]

What you described also sounds like the slip yoke binding up on acceleration from a stop. Like what Boostvalve stated, the slip yoke in the transfer case can momentarily bind. There was a service bulletin on this recommending the replacement be a nickle-alloy to prevent corrosion, which was stated to be the cause of the binding of the yoke. Definitely the same symptoms.

 

[SportsterSam]

What you described also sounds like the slip yoke binding up on acceleration from a stop. Like what Boostvalve stated, the slip yoke in the transfer case can momentarily bind. There was a service bulletin on this recommending the replacement be a nickle-alloy to prevent corrosion, which was stated to be the cause of the binding of the yoke. Definitely the same symptoms.

I could also see how putting the truck into 4x4 if possible could help to troubleshoot this, as the front driveshaft would be helping to pull the truck forward.

 

[GoToGuy]

If you pull it out of 4th or OD just drive around in 3rd, does it react the same way. That keeps the torque converter in a.non overdrive condition. Although from what you describe, continued driving with these problems could catastrophic.

 

[Schurkey]

If you pull it out of 4th or OD just drive around in 3rd, does it react the same way. That keeps the torque converter in a.non overdrive condition.

The torque converter has nothing to do with "overdrive". The torque converter clutch can still engage in 3rd gear; I'm told the 4L80E can even engage the TCC in second--but I haven't noticed that on my '97.

 

[Supercharged111]

The torque converter has nothing to do with "overdrive". The torque converter clutch can still engage in 3rd gear; I'm told the 4L80E can even engage the TCC in second--but I haven't noticed that on my '97.

It will at WOT. My 700R4 would lock up in 2nd with light throttle bit you had to put in manually into 2nd. My dually flows very little fluid at idle. It will bump off the line similarly to what the OP describes and lockup sometimes doesn't happen when I expect it to. I'll be attaching a pressure gauge to the test port soon to compare commanded pressures to delivered pressures. If I see a big discrepancy, the pressure control solenoid is likely to be my first stop. The lack of power off the line as described by the OP kinda sounds like the sprag took a dump in the converter. That'll kill the built in stall and make it act more like it's locked off the line.