Tranny Guys

[GiJoe]

Get your head out of the gutter, I've got a serious question here!

I know there are better forums or 800 numbers to pose this question too, but I like the answers I get on RCC better!


My neighbor kid asked me for advise on the tranny in his '96 Tahoe. Its a stock 350ci, 4l60e, lifted 8" on 40" Groundhawgs with stock axles and gearing (3:73's). This is a problem in and of itself! Anyways, he had a guy do a "Full Race Trannny Rebuild" ($1400!!!:shock Supposed to be good for diesel applications with torque #'s over 1000 ft-lbs. capability. Guy gave him no warranty and wont return calls. Shocker.

I feel bad for the kid because its seeing temps hit 300 degrees!!!! (has a temp gauge). He says its got full synthetic fluid, and not slipping (yet).

I asked what torque converter he is running and he told me a B&M with 3800 stall! I said no shit it its hot! Thats way too high of a stall!

My question is, what would be an ideal RPM stall convertor for this rig? My gut feeling was way lower, in the 1200 to 1500 range, but, I'm not a tranny guy!:mrgreen:

 

[ROWDY RACING]

Get your head out of the gutter, I've got a serious question here!

Then I am of no help...

 

[ped453]

I picked up a tranny once...

 

[1tonscout]

No joke I just saw 2 tranny hookers walking down the street in front of my work.

 

[GiJoe]

Enough shenanagins, this tranny is really giving this kid anxiety issues. He doesn't want to tell his old man the whole story. His dad doesn't know what he paid for it.

 

[NoobCrawler]

What's funnier than the thread title is the fact that you expected a serious answer.:mrgreen: You really should know better.

 

[thomass14]

his axles gears are a major problem 3.73's with 40 inch tires lucky the thing didn't blow yet and yes a lower stall will help but still masking the problem

 

[1tonscout]

It needs at least 5.13's"thumbsup" too bad the kid dumped the money on the trans. shoulda done a sas, got a dana 60 front, 14 bolt rear and a junkyard tranny

 

[joesbruiser]

A 4L60e build cost of 1400 is not that bad I almost have that much in just my Torque converter alone.
A good front drum,shell,boost valve,accumulators,clutch packs etc......... Could run 700.00 bucks without the cost of a converter.Then if you upgrade the 4 pin planets to the 5 pin out of a 4L65 or the even better Planets out of a 4L70 that they run in the TBSS that's even more cost.
On average in my area if you do a stock rebuild with a re man converter and R&R time a 4l60 build will cost in the 1600-1900 range depending on what hard parts are needed.
Now on to the overheating part with the shitty gearing and a junk B&M TC that stall would be way loose.I would like to watch and see when the TC actually couples up.Gearing plays a big part in stall speed.I would not have a issue with a good TC like a Circle D,Precision or a PTC converter being in the 3200 range.But that would be a custom converter that is stalled for engine,weight,tire size and axle gearing.There is a huge difference in a good converter and a cheap one.Now with that said Circle D offers a nice stock shell Converter custom stalled to the vehicle with good lockup material for around 400 bucks.We have run several and they do fine.In this truck I would go with that before spending the money on a billet can like I run in mine.
Next the stock cooler is not enough for a stock setup IMHO so a external stand alone or inline plumbed cooler is a must.

 

[joesbruiser]

I was looking around and i do not think B&M makes a converter for the 4L60E that is that big.But like I said before a off the shelf converter in the rig decribed would be way looser than advertised stall speed.
A stock GM converter is around 1400-1800 stall speed and in this rig I would guess somewhere in the 2000-2400 range wich would be a good place to be.He could always try and trade the new converter to someone with a stock unit.

 

[EeePee]

Joe's into trannies apparently.

 

[joesbruiser]

Joe's into trannies apparently.

 

[jetboat]

what I was always told about lockup rpm... drive around town/ down the highway and see what rpm you are pulling normally. Then subtract 200 rpm.

So 65 mph on the highway (if thats where 90% of your driving at) gives lets say 1800 rpm
-
200

=

1600 rpm lockup.

Stock gearing and 40" tires... who knows. If the lockup is too high, it will just sit there and build heat.

 

[GiJoe]

What's funnier than the thread title is the fact that you expected a serious answer.:mrgreen: You really should know better.

Half expected...

joesbruiser, thanks for the info. He told me it was a (used) B&M T.C. that the guy sold him. I gave him info on a TCI convertor that I ran in a tug-of-war truck. It stalled at 1500 rpm and I had great results with it. But... I was running 33" tires with 5.13's and a 460 / C6. I made a tranny cooler out of an A/C condenser with a 16" electric fan. Beat the shit out of that truck and never got fluid temps over 160 degrees!"thumbsup"

 

[docsrcrepair]

With those tires, and gearing I am surprised he hasn't smoked even a well built trans yet. Let me guess he is running a stock 5.7L too?? Big tires needs big bucks in the drivetrain to live."thumbsup"

 

[joesbruiser]

This is the way to look at it.Stall speed,flash and in the case of a lock up converter like this one there all different things.
Take the converter I run in my TBSS for instance. If you sit there with one foot on the brake and the other on the gas it will start pushing about 2800Rpm that's pretty much it. Now nail it and unload the brake or sit at a idle and nail it the converter couples up hard at about 3200rpm that is what it flashes. Now under normal part throttle driving you would not know it from stock,you let off the brake at a idle in will creep and by 1500 or so it drives right off.Now on the lock up part.with a auto trans you are going to have a certain amount of inefficiency with the converter,so on lockup transmissions they add a clutch pack in the converter that applies at a preset point.This makes them way more efficient.

 

[GiJoe]

Let me guess he is running a stock 5.7L too

Yep