Trans issue PO1870

country_09 · July 16, 2017

Have a 2001 Silverado that's my "toy" if you will. I rarely drive it but a couple years ago I roasted the stock trans bein dumb goin around a corner. Had 198k on it so it had enough. I bought a bunch of upgrades and had a buddy of mine rebuild it. Well fast forward to now and about 5k miles later, I was drivin it recently and the 2-3 shift flared up really bad(4k-5k rpm) in normal drivin. It wouldn't go into 3rd or 4th/OD at this point and the temps started climbing up pretty quick. The codes were PO1870 trans comp slipping and then another for shift solenoids. I've done some research that points to valve body wear and considerin I didn't replace any parts on the valve body besides a shift kit, that it could be the issue. But was wondering if anyone else had any input. A local trans shop told me that a new valve body wouldn't fix my issue when I called and asked how much to get the new one I had installed. I wasn't sure if it was a "bring it in and let me find somethin else to tell you that's wrong" so they could say it needs rebuild again kinda thing. Parts I bought durin the rebuild were 3k circle d stall, 5 pinion planetaries, hd2 shift kit, 40k cooler, red alto clutches, Kevlar band, beast sun shell, new sungear, and some other lil knick knacks and goodies that I can't rattle off the top of my head right now. I figure it's kind of a could be anything kinda deal but any help is appreciated.

carkhz316 · July 16, 2017

Red altos and kevlar band are meh, and unneccesary in a otherwise stock/ street pickup. As to the problem, it sounds like 3-4 clutch pack is burnt up. If everything else is good, and the valvebody is in good condition (all valves move freely; no excessive wear or binding) you could get away with just replacing the clutches themselves. As to the cause of the premature failure, how has the truck been driven and has the fluid ever been run low or hot? Unless you have access to a bi-directional scan tool to command shifis, a quick way to see if the 3-4 clutches are indeed burnt, is to unplug the main trans connector and go for a test drive. If clutches are actually intact, it will default to 3rd gear and bog trying to take off. If they are burnt, it'll take off normally (1st gear).

country_09 · July 16, 2017

They were better than stock I suppose lol. And I'm not sure if the valve body itself is good. I have the new one I can put in for shits and giggles since I'd be there anyways. And the truck is driven fairly easy, I usually just cruise the town in it. Doesn't go off-road or pull anything, no burnouts or anything dumb anymore. Fluid rarely gets over 150 with the cooler and the deeper pan. I didn't know that about the trans connector though, that's good info! I take it that's the circular plug on the side you're talkin about? Will def have to try that. And if it defaults to 3rd then the clutches are good? Where else should I look if that's the case?

txab · July 16, 2017

Why not have your transmission guru buddy fix this?

country_09 · July 17, 2017

He is the one that'll do the work, I'm not as comfortable with transmissions as I am everything else. I'm just tryin to narrow some things down before tearin it apart not knowin anything ya know.