4L80E dipstick part number? Filter differences? Dropping out of 1st gear...

[K5_489]

I have a '95 4L80E in my K5, that I converted to full manual operation...there is no ECU/TCU anywhere in this truck, shifting is 100% manual. Basically I'm now controlling the shift solenoids via the pressure manifold assembly and manual shift valve, with the line pressure solenoid locked out. Trans worked fine before I did the engine swap, though it sat for 7 months before I got the new engine in.

Issue now is extreme amount of delay going into gear..like a minute plus. Pull it out of park into reverse, wait a minute, then it grabs and goes. Back out of the driveway, shift to 1st gear, wait another minute, then it grabs and goes. Noticed it seems to drop into neutral when I come to a stop, though it seems to catch much quicker once the trans has warmed up. It will engage faster if I rev the engine a bit, and then it SLAMS into gear (which is to be expected, given that I'm running full line pressure at all times) Once I'm rolling, there's zero slippage in the trans. It barks the 33s no problem with little throttle in the 1-2 shift, and other than stopping or shifting from park to reverse or drive, there's no other issues with it.

I'm thinking I may have the trans overfilled now, as I pulled the pan and changed the filter before putting it back in the truck, and dumped 2 gallons of ATF in to it when I reinstalled the trans to bring the fluid level up to the proper level on the dipstick. Which seems like way too much, though at first I just figured it was because most of the fluid drained back to the pan from sitting so long.

I have the proper 1991 squarebody 4L80e dipstick tube in there (had to go to the dealer, and apparently I got the last one in stock), but I used the same dipstick from the '95 truck I took the trans from. Now I'm wondering if maybe that dipstick might be too short for the tube, leading to overfilling, but I can't find part numbers for any of the dipsticks themselves to see if there's a difference.

I'm also wondering if it might be an issue in the filter...when I was putting it in, it seemed like it didn't want to seat all the way in the trans. I've heard that there's a deep pan filter and a shallow pan filter, but I can't find references to either in the parts stores listings. My pan is flat on the bottom, and maybe an inch or so deep. I'm noticing it looks like the pan gasket is weeping all the way around, and wondering if maybe I have a deep pan filter installed in a shallow pan? Is that even possible? I ran all the bolts up with a torque wrench, so I don't think they're loose. I also DID replace the filter seal up in the trans case as well.

 

[bucket]

I've got a dipstick and tube from a '97 or so van with the 4L80e, I could measure how far the stick protrudes past the base of the tube.

 

[K5_489]

That would be awesome, thanks!

I dropped the pan today and changed out the Power Torque filter and seal for a Wix 58836, which according to Rockauto, is specifically for an early 4L80e with shallow pan.

Noticed I dropped about 1.5 gallons out of the pan, and the dipstick is contacting the plate just under it in the trans, with roughly 0.75 - 1 inch between the bottom of the dipstick tube and that plate. Didn't think to put a ruler up there at that point.

Buttoned it back up, and put a gallon of ATF back in, as I've read a filter change takes about 4.5 quarts of fluid to bring the level up to correct, and it covered the bottom hole in the dipstick while running.

Wouldn't engage any gear, forward or reverse, even after revving it up. Added that extra half gallon, and we're back to delayed engagement again, while the dipstick implies it's overfilled.

I'm going to pick up another couple of quarts of ATF when we run out for family dinner and see what happens then.

But I'm really wondering if the '95 dipstick in a '91 tube is going down too far..

 

[TubeTruck]

After doing a few web searches everyone has the same problem when the tranny sits. It blows the pump seal. They put a new seal in and everything is back to normal. Looks like you will most likely be dropping the tranny for a rebuild.

Check your converter engagement also. Maybe it's not seated in the pump all the way?

 

[SirRobyn0]

Your on the right track for sure. When a transmission comes in to the shop with your symptoms, the first thing we would do is check the fluid level and then pull the pan. Most commonly we find it low on fluid, or the filter clogged. Once I found a filter that was incorrect and was not sealing at the pick up. After that we'd be putting a pressure gauge on to find out what's really going on. If it were me in your situation, I'd stick a little more fluid in and then get a proper dipstick. If that doesn't fix it and your sure you have the right filter installed correctly then you'd need to tear into the transmission. My bet would be on the pump, but at the shop it would go out to our transmission guy.
Rob

 

[yevgenievich]

I can measure the length of a stock 91 4l80e dipstick from my 91 v2500. But thinking there is a seal issue somewhere in the transmission. Also full line pressure is hard on all components in the transmission if used as a daily

 

[K5_489]

After doing a few web searches everyone has the same problem when the tranny sits. It blows the pump seal. They put a new seal in and everything is back to normal. Looks like you will most likely be dropping the tranny for a rebuild.

Check your converter engagement also. Maybe it's not seated in the pump all the way?

Front pump seal? Wouldn't it be leaking fluid from there if that goes out? Every time I've lost a front pump seal in the past, it resulted in my truck resembling a crop duster going down the road, and I quickly lost all drive. While I've never tried to bolt up a trans with a converter not seated all the way (the few times I didn't get them seated, it was obvious as soon as I got the trans near the engine), it was always my understanding that it's a situation of either it's seated or it's not, and if it's not, it completely trashes the converter/pump/input shaft almost immediately...as in minutes. This one is hooking up hard once the fluid starts pumping, giving very firm shifts under moderate throttle, and has consistently been like this over several days.

Though I did read a post over on LS1tech last night where a guy said the pump to body gasket went out or was out of place, causing the same symptoms, though I think it was immediately after he pulled/replaced the pump for some reason. I'll have to see if I can find that thread again.

Your on the right track for sure. When a transmission comes in to the shop with your symptoms, the first thing we would do is check the fluid level and then pull the pan. Most commonly we find it low on fluid, or the filter clogged. Once I found a filter that was incorrect and was not sealing at the pick up. After that we'd be putting a pressure gauge on to find out what's really going on. If it were me in your situation, I'd stick a little more fluid in and then get a proper dipstick. If that doesn't fix it and your sure you have the right filter installed correctly then you'd need to tear into the transmission. My bet would be on the pump, but at the shop it would go out to our transmission guy.
Rob

I can measure the length of a stock 91 4l80e dipstick from my 91 v2500. But thinking there is a seal issue somewhere in the transmission. Also full line pressure is hard on all components in the transmission if used as a daily

It's not a daily, at all. My commute is 100+ miles round trip, and I'd much rather do that in something not lifted, with functioning A/C and cruise control, and actually does automatically shift, which the K2500 handles nicely, with a Caddy STS as a backup to that. Plus, my employer supplied work truck often comes home with me too. The K5 set up like this is definitely more of a bear to deal with than a true manual trans on the street, and while it doesn't bother me for short trips, I sure as heck wouldn't want to daily this one, lol.

I was thinking it seemed a bit odd that the dipstick came down far enough to hit that little shelf below it on the valve body, and started to bend over just a bit...like it was seating about 1/4" or so too deep. But then this is the first 4L80 I've ever been inside of, so I really don't know if that's correct or not. The cold/hot marks were still up inside the tube, though.

When I put the Wix filter in, it fully seated right away with no fuss, unlike the Power Torque filter that I put in prior. Even when I dropped the pan, the Power Torque filter had about 3/16" gap between the bottom of the seal and the ridge on the filter tube, whereas the Wix filter fully seated when I pushed it up.

I did eventually find pictures of the shallow and deep pan differences for the 4L80, and mine is definitely a shallow pan. All the filters I was looking online for the 4L80 shallow pan appear the be the same as what I have now, as well as the filter I pulled out before the Power Torque went in, so I'm fairly confident that the correct filter is in there.

Though, come to think of it, I've never had a proper dipstick/tube combo in there since I put the trans in. I found that the '95 tube out of the Suburban I pulled the trans from didn't come remotely close to fitting in the '86, so I cut the bottom of the tube, put a piece of heater hose in there, and connected it all back up, only to find it virtually impossible to get the dipstick through that section...never did get it to fully seat, and ended up just filling up the pan until it started grabbing, and then added 2 more quarts for good measure. Though I didn't have the presence of mind to record how much I dumped down there for that to happen.

I just looked up info for TOTAL capacity of the 4L80 trans, as opposed to pan capacity (or, in other words, how much drops out during a filter service), and found that it definitely seems to vary according to application and vehicle installed, largely between 12 and 14 quarts total, including converter, with the general split being roughly 6-7 quarts between the converter/cooler/lines, and 7-8 in the pan. Based on that, given that I installed a dry radiator, and the trans sat long enough for every possible drop of fluid to go down to the pan, putting 2 gallons in when I started the motor up for the first time now begins to make sense. I also dropped roughly 1.5 gallons out of the pan when I changed to the Wix filter...which would appear to imply that I am in fact low about 2 quarts now, and 2 quarts low seems to be about where issues start showing up on transmissions.

Of course, I don't really _want_ to pull this thing back out, especially being that I just went through it when doing the full manual mods, when I put it in the first time..but if it comes down to it, it's not all that big of a job to pull it again. I can have it on the ground in 30 minutes easy, and a front pump seal/bushing/gasket/o-ring is a quick and easy change out with the parts being dirt cheap from my local supplier, so that's not the end of the world. I just know that if it comes out, "while it's out, might as well blah blah blah" project creep sets in REAL fast, and before I know it, my wallet is another couple grand lighter with a bunch of upgrades sitting on the bench, and the truck will be down another few months until I get around to building a trans, lol.

So yeah...I figure I don't have much of anything to lose at this point by tossing another couple of quarts in the pan

Hey @yevgenievich , by chance is there a part number stamped on that dipstick? I'm at work now, so can't check mine, but I seem to recall that the part number is stamped right in to these things, which would help greatly when I visit the dealer....I've learned to go in armed with part numbers as opposed to make/model/year, and I'm having difficulty pulling up that info online at the moment.

 

[yevgenievich]

Part number 15659454. About 32 3/16" long.

....

 

[bucket]

^^^Glad you could measure that. I couldn't find mine. Found one for every other skinkin transmission, but not that one.

 

[K5_489]

Yep, different than what I have now, appears to be a part specific to the '91 R/V 2500/3500 trucks (not that I'm surprised by that either), and unavailable everywhere. Looks like I'll be crossing my fingers, saying a prayer in 2 dozen different languages, and hoping I find a '91 in a junkyard somewhere....

Or maybe I can just transfer some measurements to my current dipstick.

I picked up another couple gallons of ATF today, and dumped another gallon into the pan. Started at 2 quarts, thinking I already had roughly 6 quarts in the pan, so 2 more would bring it up to the 8 quart level I found earlier. It got a whole ton better, but still had a delay going into gear. But now it was more like 5 to 10 seconds, rather than 60. So I dumped the remaining 2 quarts in, so I should have roughly 10.5 quarts in the pan, and much improved again, down to 2-3 second delay.

Which I would otherwise be OK with (not saying it's right, but I could live with it for a while), but I noticed it's still dropping out of gear at idle. It only takes a couple hundred RPM to get it back in, but I know that's not right either. Also found that it doesn't have any engine braking in any gear, and won't downshift without throttle either..like I'm cruising at 35mph in 4th gear, take my foot off the gas, RPMs drop to 1,000, I pull it back into 1st gear, and no change. I blip the throttle, and THEN I feel it downshifting.

Oh, and it's getting hot now too...I have a temp sensor in the test port, and an easy jaunt around town got it up to 220*. I'm going to double check the lines to the cooler, but I'm not holding my breath on that being an issue/solution to all this mess either.

So yep...looks like I get to go through this trans again....

 

[SirRobyn0]

So what you are doing is fine and I've had to go though it a time or two. What I would do is continue to add 1 quart of fluid at a time until it seems to be working correctly, but don't go beyond the total fluid compacity. Assuming you hit a point where it is happy, add one more quart and mark the dipstick. If you hit total complicity and it's still not working correctly then there is an internal problem.