2nd gear is intermittent and won't hold power occasionally

kott0n

Original poster
Member
Apr 8, 2019
13
WA
Hey guys

I picked up a 04 Buick Rainier 5.3l awd. It was skipping 2nd gear.

I got new shift solenoids in and it will now shift into 2nd gear. The fluid was literally black, not good. Looked worse out of the trans than on the dipstick, that's for sure.

New issue is sometimes 2nd gear will "hold" the power and sometimes it will not even try. When it does grab it will stay until redline like it should. When it doesn't grab it will free wheel like you have the clutch in on a manual. This is when manually selecting 2nd gear.

It will never "hold" the power when you have it in drive and let it power down shift. If it downshifts into 2nd under WOT it will just free rev.

It also will never shift it self under WOT power. Wont do 1-2 or 2-3.

I uploaded a few videos. I guess I didn't get one of it free revving with 2nd manually selected but its the same effect as the videos when its in drive and you command a downshift to 2nd. Filmed in mexico.

This is manually selecting 2nd gear and where it held power to redline like normal.

Downshift to 2nd then freerev

Another downshift freerev


I think it might be the servo? Since it is intermittent. I feel like if it was the band then it would never hold and it does most of the time and 4th would slip and from what I can tell it doesn't but its hard to test.

All the shifts are super lazy. I mean 4 second shifts.
I'll be able to test the servo for play probably next weekend.

Think this is the right track?
Any help is appreciated

Mod edit: Edited your post for proper links to YouTube.
 
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mrrsm

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Oct 22, 2015
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Welcome to GMT Nation...

(1) Perform a COMPLETE Transmission Flush that includes Isolating and Flushing out the Transmission Fluid Cooler and Lines (Do NOT Back Flush the Lines through the Transmission) as shown by @MAY03LT in the second Video:



(2) If the Vehicle was used for Towing a great deal... the Friction Plates and Steels may already just be Seriously Worn Out and the Color and Condition of your Old Transmission Fluid indicates this by its excessive Dark Contamination. Your videos indicate that perhaps ...you have a regular and natural habit of "Getting On The Gas Pedal"...ergo... which can prove to be a contributing factor in the vehicle's problematic Transmission Performance.

(3) Be careful with doing so much Over-Revving of the Engine... approaching The Red Line as you might incur unintended damage to the Motor as well as doing more damage to the Transmission while trying to force these bizarre downshifts to present themselves under stress while driving down the road.

(4) Testing out things in the manner shown in your videos is something akin to making a Man with a Known Heart Condition run 440 Intervals over and over in the hopes that his situation will improve. This is not a recommended diagnostic technique after such a serious problem presents itself... Brother... We'll take your word for it!
 
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Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
And if the full fluid exchange doesn't help, I would consult a tranny shop. If the fluid was as burnt/black as you say it was, it may well be done.
 
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Mike534x

Member
Apr 9, 2012
894
With the money being spent on buying all the fluid to flush it out properly, seems a bit more feasible to snag a junkyard pull. I see it this way, if the flush works, how long will it last? Perhaps the gunk and everything else in the tranny is what allows it to still have some functionality. I'm not too familiar with transmission innards, but I always figured it was similar to flushing sludge out of an engine where it'll potentially cause more harm then good.
 
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Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Some say that old fluid holds clutch material in suspension and helps the worn out clutches grab. However, this is just holding off the inevitable and the flush just made it happen quicker. This is what feeds the "anti-flush" crowd that would say flushing kills trannys. Exception for those that use flushing machines that actually flush fluid backwards and sends crap back into the tranny, a fluid exchange as explained above would not do this using the normal direction of flow.

One thing that is possible is that a check ball may have punched through the metal separator but I do not know enough about their function to know if this is possible.

Beyond that, I'm with @Mike534x , I think it's beyond anything you could normally throw at it.
 

kott0n

Original poster
Member
Apr 8, 2019
13
WA
I really appreciate the response and MAY03LT videos have already helped me diagnose and fix a body control module. I couldn't be more please with this site so far, thank you guys.


Well that is kind of what I'm thinking also. I hate to keep throwing money at this heavily beat on transmission. This is about the mileage range they seem to last to, it has 144k on it.

I want to make it a sleeper. It has all the options an Its not a DD so I can take my time with it. I plan on: Some nice used take off 2in valve heads, some beehives springs, stage 2 cam but not sure on which it will depend if I go turbo or blower. The rest I cant decide on fully yet: go single turbo with a flipped manifold and fab up all the hotside which would be my first attempt at this or go CTSV take off blower then do headers to a electronic dump and tuned for the dump. I'm leaning towards turbo because it would be a real challenge. Lower it, get some 8in wheels/265 tires, might be 255 that fits? I remember seeing the upper control arm is pretty close to the tires on the front.

I want to bring this to 2wd eventually. It has the 3.37 with limited slip. So this brings me to right now... do I continue to troubleshoot and throw money at this awd 4l60e or go grab a junkyard 4l80e 2wd and ditch the 4l60 and tcase, front drive line, cv's and eventually swap out the oil pan that has a hole though it? I realize the junkyard 4l80 might also be garbage but then I at least have a core to send off. I feel if Im going to throw money at a trans, it might as well be a 4l80. Is that crazy?
 

Maverick6587

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Dec 16, 2018
730
Sterling Heights, Michigan
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mrrsm

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Oct 22, 2015
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Strictly on the Engine Side... this Link may interest you if you decide that you want to build up your Motor on a Budget. Disregard that it involves a 2000 Chevrolet Silverado 1500...in this case... the focus is on improving the 5.3L Motor:

 
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TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,047
Brighton, CO
Just curious, where did you get the info about a 3.37 LSD? Is this something you did? Thats not a factory diff gearing.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
You should should have a 3.42 or 3.73. Typically with the 5.3 and posi, should be 3.73.
 

kott0n

Original poster
Member
Apr 8, 2019
13
WA
I appreciate the responses! I already grabbed the manuals from Mooseman's sig, thank you!

I am also leaning to putting the 4l80 in there. I've already read how to do the pin swaps on the harness and am prepared to get HPtuners and do the segment swap. I was going to get HPT anyways.

I for sure am looking for a proven recipe, I'm not trying to reinvent the wheel. A common parts build is just what I need, thank you! I had a 2000 Firebird LS1/T56 many moons ago but all I did was full exhaust, so I'm green but I've done a ton of research and reading. Done with school, married, kid, house etc now and wanting to get back into going fast!

This Buick was so cheap I was originally just going to pull the motor/harness and have a plethora of bolts left and scrap it (oof). Tbh it was so clean and after some troubleshooting all the gadgets work perfectly and its all clean interior/exterior. Since the wife actually likes it, I think it this would let me spend more go fast money! I've actually really started to like the lines myself so the plan is to just build this into a sleeper now.

You guys are right, I typo'd it. It has the G80 RPO which I've read is the 3.73 LSD rear which is perfect.
 

kott0n

Original poster
Member
Apr 8, 2019
13
WA
I agree on changing the needle bearings out. Its cheap money/labor insurance and gives peace of mind. If I was just driving a stock LS as is, I wouldn't even know it needed done. The people that have discovered the issue are the ones who putter beefier springs in then run a ton of seat pressure via boost.
 
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TollKeeper

Supporting Donor
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Dec 3, 2011
8,047
Brighton, CO
G80 is just the locking rear diff

You are looking for codes like GT4 (3.73) GT5 (4.10) or GU6 (3.42)
 
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Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
You sure it's a G80? The AWD trucks got the G86 LS Diff. 4x4 (TB/Envoy) trucks got the G80 locker. If you plan on putting a lot of power to the pavement, you might have to source a TB SS diff.

At least yours is an '04 and don't have to worry about deleting DOD.

A truck like that would make a good sleeper.
 

kott0n

Original poster
Member
Apr 8, 2019
13
WA
Okay, good call out. I'll look tonight. Honestly any of them would be fine with me but I believe 3.73 to be a great ratio for a street/play car.
 

kott0n

Original poster
Member
Apr 8, 2019
13
WA
So I see GT4 and G80 on my RPO sticker on the glove box. This pleases me!

88147

I saw in the other thread you guys are putting the selectable transfer case into the Saab's with no issues. That puts more options on the table and more to think about.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
OK, that is a first. Maybe it was a customer request on the build?

Anyway, the locker may not be what you want, nor a 4x4 transfer case, for a street bruiser. The G80 is known to explode with too much power and/or traction, basically designed more for loose traction situations like off-road. And the 4x4 transfer case is also not designed for high traction situations neither with a solid front/rear driveline connection evident with crow hopping while turning on asphalt. Unless you want to turn into an off-roader?
 

Mike534x

Member
Apr 9, 2012
894
I couldn't find a complete trim level list, but it looks like the Rainer came standard with 3.73's (2WD or AWD) with 4.10's being optional. This site seems to contain the build options available at the time, seems like it had all the features the Denali came with prior to 05. If he wanted to keep it AWD, I wonder if fitting in a transfer case from an AWD GMT800 would work? I'd imagine those would handle the beating/power output.


https://www.autoblog.com/buy/2004-Buick-Rainier-CXL_Plus__All_wheel_Drive/pricing/
 

kott0n

Original poster
Member
Apr 8, 2019
13
WA
The plan is for sure a street build so leaning more towards the original plan of doing an 80e 2wd swap. Yeah I figure I will find weak points as I really only plan to beat on it.

I had found an options list at one point, I can't find it now. It has things like: Driver 1 and 2 mirror/seat/peddle settings, electronic peddle position, passenger mirror that points at the curb when you put it into reverse, it has the old school navigation that requires discs (lol) but it is DVD, it even has a recorder built into the ceiling console. There was actually conversations from previous owners in there, was strange! It even has laminated glass, extra sound deadening, dual climate, leather, heated seats, the rear air shocks like other models but also has a built in pump in the hatch area to pump up air beds/beach shit or whatever, Onstar but already pulled the fuse and will be removing the box (even though it supposedly cant communicate as too old), etc.

Anyways, they were really nice and should make a great sleeper. I'll make a build thread when I start on it I guess. It had a dead oil pressure sensor and was leaking out of it, oil all over the back of the block and bell housing. I fixed that and cleaned it up real good, not a drop since. I'll do the rear main and cover when I pull the trans just for peace of mind. I plan on using a Sac City Corvette tool for the rear main, just makes sense.

Who suspects a Buick suv with 450+ whp? Should be fun.
 
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Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON

kott0n

Original poster
Member
Apr 8, 2019
13
WA
I had to look that up. Cool tool!
Video here.
Yeah, it's pretty slick. I guess GM has an official tool for it but these are pretty cheap to have around.

Again, this kind of stuff is just peace of mind for me. Last engine I tore into/modified was a Mitsubishi 4g63T over 12 years ago. I haven't ever wrenched on a LS and since I can really take my time with this, I want to do things proper.
 
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gmcman

Member
Dec 12, 2011
4,656
FWIW, I feel the seperator plate should be replaced every 150K...at the longest interval.

The check balls tend to hammer their way through the plate and can/will cause pressure issues.

If your trans starts to slip or flare at any moment...let off the gas. The clutch packs and/or the band will get smoked real fast like this. Once the band goes, game over.

I would change the filter, exchange the fluid and if it were mine, I would get a new separator plate FROM THE DEALER ONLY...just friendly words of advice. The plate will be vin matched to your specific vehicle/options.
 
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Sparky

Member
Dec 4, 2011
12,927
I use hardened separator plates from Transgo in my 4L60 transmissions.

But it sounds like that one may be too burnt to put much effort into anyway.
 

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