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At the advice of mrvedit I am going to do my best to outline and cover this build.
Long story short we purchased an RPM Transmissions Level 5 4L70E in Dec 2013, it was installed in our TBSS in Jan 2016 (the truck was being overhauled). From there it only lasted 6000 miles, survived Drag Week 2016, made 10 passes on the drag strip with a best of 11.9 @ 116mph on a 1.6 60', and **** the bed cruising on the highway. Following the failure RPM Transmission decided to dismiss any responsibility or provide any measure of service after the sale; and pointed fingers at the tune (which was returned to stock parameters at their direction).
The truck has sat broken for a year now; and to date we only know what it stopped doing (shifting into 3rd or 4th) and what drained out of the pan (complete with Level 10 glitter); but we will autopsy it soon (and document as much as reasonable).
The plan:
1. Keep it AWD (hence my abandoning the idea of putting in a 4L80E that we purchased, and thus converting it to 2WD);
2. Not accept that a glorified "shift kit rebuild" is acceptable for anything this heavy or powerful; and
3. Data log the pressures and actually tune the truck.
The parts:
1. 0-250 psi pressure transducer (will be connected to HP Tuners);
2. Yank 2600 Truck Thruster (going to need to be cut and cleaned);
3. Sonnax Smart Tech 3-4 Input Drum;
4. Sonnax Heavy Duty Output Shaft (300M);
5. Sonnax Sure Cure Kit;
6. Sonnax Heavy Duty 2-3 Shift Valve;
7. Sonnax 2nd Gear Super Hold Servo Kit;
8. Sonnax 4th Gear Super Hold Dual Servo Kit;
9. Sonnax SmartShell® Heavy Duty Reaction Shell Kit;
10. Sonnax Billet Forward Clutch Piston; and
11. Billet Input Shaft (300M with the ISS reluctor).
We are going to add a proper wide band, BW Hi Energy frictions, and any other updates to the mix too; as well I picked up another case of AMSOIL ATL (the last stuff didn't burn up when the RPM Transmission failed).
I am still humming and hawing on using a 13 vane pump. So if there are any other tips I sure would appreciate them.
Last edited by mOtOrHeAd MiKe; 10-05-2017 at 09:48 PM.
Dropped the pan today (Oops! The filter had screw in it through the pan from when I drained it - LOL). Looks totally normal for a tune issue and a set of fried 3/4 clutches... riiiiiight...
Dropped the pan today (Oops! The filter had screw in it through the pan from when I drained it - LOL). Looks totally normal for a tune issue and a set of fried 3/4 clutches... riiiiiight...
I'm in the same boat as you captain.
Question: Where do you find pumps for these? Since they have the speed sensor on the back, Im not sure if a 4L60e pump is the same???
I am under the impression my pump died, the good news is that if these pumps are hard to find I do have a complete working spare tranny to build if this R(eally)P(oorly)M(anaged) unit is junk.
Last edited by mOtOrHeAd MiKe; 10-06-2017 at 01:55 PM.
You don't need a 300M input shaft.
Looks like you already have a larger 4th servo piston.
The Sonnax sure cure kit requires 3 tool kits to install.
The factory steel forward piston is plenty strong.
What reaction sunshell is in the trans now?
I would run a billet 10 vane pump rotor & Trans Go high rev pump rings/Primer spring in this kind of build.
If the valve body didn't get destroyed by all that metal (Looks like Aluminum??).....I would clean it really well, Check that the HD2 kit was installed correctly & run it.
-Blocking the 3-2 valve inboard is crucial for 3-4 clutch life, Sonnax does not recognize this in any of their kits. The HD2 does.
-The Sonnax servo release check valve works "OK" in stock builds....But not on performance builds.
-The Trans Go TCC PWM delete valve works very well! No need to go through the expense of the Sonnax fix.......The ONLY reason I have the tool Sonnax tool kits for the TCC regulator & Isolator Sleeves is because "Displacement on Demand" vehicles require retaining the PWM function.
-4L60E variants are not to bad about wearing the AFL bore.
-Check the PR valve for excessive wobble while holding the valve 1/4" from bottom, If it checks OK.....No need for the oversized Sonnax piece. Your Pump Body & Cover may be trash anyway will all that metal!!
Using a Sonnax Pinless accumulator piston in the 1-2 accumulator housing can be problematic when paired with a super hold 2nd servo piston.
The piston is limited in travel & will make for a very harsh 1-2 shift!
You cannot use the "over-under" HD2 accumulator springs which are quite effective at extending the range of the accumulator IF the spacers are left out! We do this to ALL 700R4's.
-If you insist on using the Pinless Piston.....Use GM# 24209794 ovate outer spring & GM# 24220146 inner spring (Works with you late housing), Stack it like factory. Be conservative with the 2nd feed hole with such a low stall converter (Start with .081").
Reuse the Blue Trans Go inner servo cushion spring, If it wasn't installed.....Use GM# 8681195.
Sonnax 4l60E-LB2 is the part# for the short boost valve for your ISS pump cover.
Your converter may have failed, Sending a heavy amount of aluminum through the unit.....Clogging the filter & smoking the 3-4 frictions.
You may want to calm down on the mud slinging 'til you figure out what happened. You had the unit for 2 years before it was installed.
This has already been purchased, as have all of the other hard parts listed.
Looks like you already have a larger 4th servo piston.
There is definitely one in there - who made it we don't know. For the cost I'd rather have a known quantity.
The Sonnax sure cure kit requires 3 tool kits to install.
The shop I am working with is familiar with and comfortable with the Sonnax product line.
The factory steel forward piston is plenty strong.
Good to know thanks!
What reaction sunshell is in the trans now?
Unknown at this time we should know tomorrow.
I would run a billet 10 vane pump rotor & Trans Go high rev pump rings/Primer spring in this kind of build.
I'll pass this along to the builder.
If the valve body didn't get destroyed by all that metal (Looks like Aluminum??).....I would clean it really well,
Yes, mostly aluminum and what looks like some brass too.
Check that the HD2 kit was installed correctly & run it.
That is part of the teardown plan to look for a root cause of the failure.
-Blocking the 3-2 valve inboard is crucial for 3-4 clutch life, Sonnax does not recognize this in any of their kits. The HD2 does.
I will pass this point along. Thanks!
-The Sonnax servo release check valve works "OK" in stock builds....But not on performance builds.
Again, I'll run this past the shop.
The Trans Go TCC PWM delete valve works very well! No need to go through the expense of the Sonnax fix.......The ONLY reason I have the tool Sonnax tool kits for the TCC regulator & Isolator Sleeves is because "Displacement on Demand" vehicles require retaining the PWM function.
I used the Sonnax TCC PWM delete in the 4L60E in my wagon and it seems to be working well. Best, I can tell the PWM function in the RPM Transmission was still working as designed given I could tune the engagement pressure through HP Tuners.
4L60E variants are not to bad about wearing the AFL bore.
We are going to go through the VB to check for wear - it isn't like this was a new unit.
Check the PR valve for excessive wobble while holding the valve 1/4" from bottom, If it checks OK.....No need for the oversized Sonnax piece.
Thanks for the tip. We will definitely not be making changes for the sake of making changes.
Your Pump Body & Cover may be trash anyway will all that metal!!
My thoughts too - good thing I have a spare.
Using a Sonnax Pinless accumulator piston in the 1-2 accumulator housing can be problematic when paired with a super hold 2nd servo piston. The piston is limited in travel & will make for a very harsh 1-2 shift!
Good to know. I am using both of these parts in my 4L60E and it seems to be working great.
You cannot use the "over-under" HD2 accumulator springs which are quite effective at extending the range of the accumulator IF the spacers are left out! We do this to ALL 700R4's.
Interesting, thanks.
-If you insist on using the Pinless Piston.....Use GM# 24209794 ovate outer spring & GM# 24220146 inner spring (Works with you late housing), Stack it like factory.
Great, thanks.
Be conservative with the 2nd feed hole with such a low stall converter (Start with .081").
Tracking, thanks.
Reuse the Blue Trans Go inner servo cushion spring, If it wasn't installed.....Use GM# 8681195.
Again, thanks.
Sonnax 4l60E-LB2 is the part# for the short boost valve for your ISS pump cover.
I am almost positive this is in the Sure Cure kit. I know it was in the Performance Pack I installed in my 4L60E.
Your converter may have failed, Sending a heavy amount of aluminum through the unit.....Clogging the filter & smoking the 3-4 frictions.
Wouldn't that be one hell of a surprise from a Yank converter. It is going to get sent out to be cut and cleaned.
You may want to calm down on the mud slinging 'til you figure out what happened. You had the unit for 2 years before it was installed.
My feelings on this matter were far more open-minded following the failure until RPM Transmissions treated me so poorly while seeking a solution. It is fully documented here: http://www.tbssowners.com/forums/4l7...l-5-today.html I am all about full disclosure and personal accountability when it is applicable (I raced and broke my truck; it was my choice, my problem). I doubt transmissions are known for failing by sitting on the shelf - if that is what you are getting at. If it is the fact the warranty period lapsed, I accept that - even if finding some common ground and an amicable solution would have been a preferred course of action.
I am only interested in the root cause of the failure and building a better transmission at this stage - and to refrain from racing it. But, if I seem jaded it is with good cause in my mind.
All this being said, I do appreciate you taking the time to offer up your experience and advice.
Last edited by mOtOrHeAd MiKe; 10-06-2017 at 06:54 AM.
looks like it had a hard part fail with all that metal lmk what the shop finds
Not a lot of carbon mixed in with all of that aluminum. I am expecting a call later today - I asked that they photo document what is found and take some measurements too.
Soooo... I got a quick update today: the torque converter died and took the pump with it (more or less - might be a chicken and egg situation). While damaged, the transmission is still useable (going to need a soft rebuild and some bushings at a minimum). We are also looking at the possibility of starting fresh with the untouched factory trans I have here. Either way we are going to put the quality hard parts into it.
Now the question is why did this happen?
And, is it worth fixing/reusing this Yank converter? That sounds like a lot of faith to put in something that broke once.
This lists the 70E: [url]http://www.americanpowertrainwarehouse.com
DO NOT ORDER FROM THEM
I have been ripped off twice by them! never received my parts, both times. Never answered a call, never answered an email, never answered an online message. But they took my money!
After the fact, i looked at the reviews, and everyone has had the same issue.
Soooo... I got a quick update today: the torque converter died and took the pump with it (more or less - might be a chicken and egg situation). While damaged, the transmission is still useable (going to need a soft rebuild and some bushings at a minimum). We are also looking at the possibility of starting fresh with the untouched factory trans I have here. Either way we are going to put the quality hard parts into it.
Now the question is why did this happen?
And, is it worth fixing/reusing this Yank converter? That sounds like a lot of faith to put in something that broke once.
It's basically a stock 278mm converter that's been reinforced with some brazing & a New hub. These converters are known to drop the torrington bearing behind stock engines.......Very poor choice for forced induction/power adder applications.
If you want to stick with a sub 3000 stall, A 10.5" billet front converter is probably the route you need to take.....
It's basically a stock 278mm converter that's been reinforced with some brazing & a New hub. These converters are known to drop the torrington bearing behind stock engines.......Very poor choice for forced induction/power adder applications.
If you want to stick with a sub 3000 stall, A 10.5" billet front converter is probably the route you need to take.....
No reason you can't tow with a 10.5" converter, a 278mm converter isn't much bigger than that.
How much is a Trailblazer SS rated to tow anyhow?
About 6000lbs.
Ironically (?) I purchased a 3200rpm Coan TC from RPM at the same time as the transmission. Unfortunately the bill of sale doesn't state the model or details. All I know is that it has a billet front cover and it isn't tiny. It is currently in our LS-swapped station wagon, and is a bit tight - being that the car is at least 1000lbs lighter than TBSS with less power it makes sense. It would be a hassle to pull it out, but it might make sense since the application isn't a match for the wagon.
Stopped into the shop to take a look-see at the internal carnage of the trans. It definitely needs all of the soft parts replaced; the band had aluminum chips imbedded in it. As for the hard parts most everything survived - the only real casualty was the pump housing (destroyed) and the billet 13 vane rotor (looks scored). It looks like it has a Sonnax SmartShell already and a few other updates and modifications - the only thing special about the clutches is the increased 3/4 count. I really should have grabbed some pics on the bench.
I ran State-side today to pick up the new hard parts listed above. The billet input and output shafts are pretty sexy. Managed to get the wrong Sure Cure kit from Summit, seems their catalogue carries the SC-4L60 (which I was sent) and the HP-4L60E-01; but not the SC-4L60E like I required. I asked Summit to add it and get back to me about a replacement - but I may not be able to wait.
Right now the shop and I are trying to decide if we are going to fix and modify the RPM unit, or start from scratch with my virgin 4L70E.
the only thing special about the clutches is the increased 3/4 count.
Stock Borg Warner frictions work great.....
The forward clutch is "static" in all forward gears, Stock face grooved paper frictions are more than adequate at high power levels.
The Overrun clutch is also static unless you downshift into lower gears at zero throttle at speed.
Lo-Reverse burn-up hasn't been a issue since the Valve Body/Manual Valve change in 1995.
The 2/4 Band & 3/4 Clutch are "dynamic" & High Energy Carbon is factory, This is the absolute BEST material for these 2 locations....Alternate/Aftermarket/Performance Tan/Red/Blue have been problematic in the 3/4 clutch.
Adding Frictions to the 3/4 clutch is really the ONLY way to add Capacity assuming adequate line pressure is present.
The forward clutch is "static" in all forward gears, Stock face grooved paper frictions are more than adequate at high power levels.
The Overrun clutch is also static unless you downshift into lower gears at zero throttle at speed.
Lo-Reverse burn-up hasn't been a issue since the Valve Body/Manual Valve change in 1995.
The 2/4 Band & 3/4 Clutch are "dynamic" & High Energy Carbon is factory, This is the absolute BEST material for these 2 locations....Alternate/Aftermarket/Performance Tan/Red/Blue have been problematic in the 3/4 clutch.
Adding Frictions to the 3/4 clutch is really the ONLY way to add Capacity assuming adequate line pressure is present.
I am not doubting that just stating what was found. The trans worked fine for what it was asked to do. The shop is suggesting GPZ clutches vs. the High Energy clutches I had mentioned. I am just looking to add a margin of reliability to the overall package with the 300M shafts and the Smart Tech drum.
I am also looking forward to putting the pressure transducer on the case and mapping/tuning the line pressure.
Again, it is tough when your confidence gets shaken in moments like this - if over building it to the tune of $1200 is what it takes to regain that confidence, so be it.
I am not doubting that just stating what was found. The trans worked fine for what it was asked to do. The shop is suggesting GPZ clutches vs. the High Energy clutches I had mentioned. I am just looking to add a margin of reliability to the overall package with the 300M shafts and the Smart Tech drum.
I am also looking forward to putting the pressure transducer on the case and mapping/tuning the line pressure.
Again, it is tough when your confidence gets shaken in moments like this - if over building it to the tune of $1200 is what it takes to regain that confidence, so be it.
Nothing wrong with Raybestos GPZ frictions, They are also "High Energy", The thing is....Raybestos advertises them as High Performance & "Better Than" OEM Frictions which is not the case when compared to OEM Borg Warner 3/4 frictions. "Equal To".....Sure!
I'm not bashing Raybestos as I use their products also.....Got Raybestos HD Graphite frictions in the Direct & Intermediate packs in my 4L80E!
10-04-2017, 08:41 PM
4L70E Build for TBSS 
