transmission woes

[RAM1964]

2011 3500 Trans has always done as advertised, not now,here's *, some background ...83,000mi tow 42' cardinal once, twice a year. Smarty me deletes done at 38,000like I said runs awesome, no hot foot nice new easy I drive, too expensive otherwise. Took trip over weekend 1200mi all good till we get back in D.C. traffic and all of a sudden it's stuck in 4th gear, will not shift, go to neutral, no shift, press shifting toggle on gear shift....still 4th. Drove like this for maybe 10miles and checked Trans fluid temp ...prefect, 150*-165* ambient temperature 95*. Pull over and turn truck off for a few min and start back out all good as far as not stuck but it searches *gears in between 1st and 2nd multiple times every time unless really easy on fuel and 6th is in and out of lockup so fast and furiously that I can't tell if it's locking up as it is shifting or what, but again rapid fire. Through 2 codes *P1790 and P0732. I'm lost and don't want to sign away the grandchildren to get it fixed, any help would be greatly appreciated. *Wade

 

[transe]

P0732 is Gear Ratio Error in 2nd, which means it is slipping in 2nd gear (as you've obviously noticed). Second gear uses the UD and 2C clutches; your problem is the 2C clutch. 2C is also used in 6th gear, and apparently you have issues there also, so that points to 2C as the cause. Also, the UD clutch is used in 1st, 3rd, and 4th gears, so if it's not slipping in those gears, then UD should be OK.

My bet would be you have a cut or torn seal on the 2C clutch piston. The 2C clutch pack is also probably burned due to slippage. Unfortunately, you have to pull the trans and tear it down to get to the 2C clutch pack and piston.

 

[RAM1964]

Thanks Trans engineer, you gave me hope but do,you know what could have caused this so I may not do it again if it was me, I know I have the smarty and have it bumped up and have only wot the truck 7-8 times in 43,000 miles and none recently only once pulling trailer 2yrs ago. Again thank you. Wade p.s. it has performed flawlessly, til now

 

[transe]

Thanks Trans engineer, you gave me hope but do,you know what could have caused this so I may not do it again if it was me, I know I have the smarty and have it bumped up and have only wot the truck 7-8 times in 43,000 miles and none recently only once pulling trailer 2yrs ago. Again thank you. Wade p.s. it has performed flawlessly, til now

I don't think it's anything you did. The 2C piston has the seal lips bonded to the metal piston, and what usually happens is the seal separates from the piston (gets peeled off of it) in one area, which then tears the seal, causes a leak, and allows the clutch to slip.

 

[RAM1964]

Hi there Trans engineer, just had Trans rebuilt at ******* ship, torque converter rebuild kits $2700 and we'll now it shudders in between 5-6 and,I'm sure it's a lock up problem, is it going to learn how to do it right or am I just getting ready for another fail ? Haven't talked to them yet but will later today and was hoping for your input before I do as I/you impressed them with knowledge when i took it in thanks Wade any help would be immensely appreciated.

 

[transe]

Hi there Trans engineer, just had Trans rebuilt at ******* ship, torque converter rebuild kits $2700 and we'll now it shudders in between 5-6 and,I'm sure it's a lock up problem, is it going to learn how to do it right or am I just getting ready for another fail ? Haven't talked to them yet but will later today and was hoping for your input before I do as I/you impressed them with knowledge when i took it in thanks Wade any help would be immensely appreciated.

Do you mean it shudders in 5th and 6th gears (when you step into it when TCC is locked), or do you mean it shudders during the 5-6 upshift? If the latter, that may indicate a continued problem with the 2C clutch (which is being applied during the 5-6 shift). I assume they re-learned it (did a quicklearn) after the rebuild? If not, they should. If they did, then I would drive it a while and see if it improves. It may just need to learn in a little more.

Try this if you can: Have them check the CVI values, noting in particular the Alternate 2C CVI. The normal range for this CVI is 46 - 73. See if yours is within this range. Then run another quicklearn, and see what that value changes to. Write both values down. Then drive the truck for a week or so, and have them re-check the Alt 2C CVI. Recheck it a few times over a couple weeks. If it is learning ever higher and higher (for example, was at 67, then after quicklearn it got reset to 52, then after a week it was at 69, then a few days later it's 76, etc.), then you likely have a continued leak in the 2C clutch passage somewhere. If that CVI value stabilizes (within the normal range), then 2C is probably OK.

 

[RAM1964]

Thank you so very much. And it was 5-6 up shift . All good now but on another front, what do think about the plug n play line booster for max pressure to clutches as the pump only puts out max of 160 psi and I believe these 68s are running with 145 psi , there are two companies putting them out bd and some other one I can't recall right now. Would you put that into play for a little more holding power?

 

[transe]

Thank you so very much. And it was 5-6 up shift . All good now but on another front, what do think about the plug n play line booster for max pressure to clutches as the pump only puts out max of 160 psi and I believe these 68s are running with 145 psi , there are two companies putting them out bd and some other one I can't recall right now. Would you put that into play for a little more holding power?

I'm not a big fan of the line pressure "boosters." Actually the pump puts out about 170 psi max in Drive, and the 68RFE already calls for up to 160 psi, so there is not much additional headroom. The "boosters" will give you a small increase in line pressure, but probably not as much as you'd expect. Also, I have seen some reports of LP boosters causing shift issues (inhibited upshifts into upper gears), although I don't know offhand why that would happen.