4L60E torque converter question, better cooler

[LVJJJ]

Been drivin' since 1962, but still don't know how automatic transmissions work. Gotta '94 k1500 GMC Burb in which I have installed a 383 stroker (incredible engine!!) Have been towing 5000 lb travel trailer in 4th on level roads. When going up a slight hill it feels like its shifting down but its not going into 3rd. Stays in 4th but rpms jump about 200. Seems like I've got an extra gear. Once up the hill and back on the level it shifts back up and rpm's drop about 200 rpms. Same thing can happen if I'm in third, usually against a headwind. Trans has not been running hot during these times.

So, what's happening when it "shifts down" slightly? I've heard it has to do with the torque converter "locking up?" or "unlocking?"

Since I do like to tow in 4th and I know that high temps are what kills auto transmissions, I was fortunate to find Saatr's 2010 post about upgrading to a B&M 70266 cooler. Ordered one and am going to install it before we tow from here in Blaine WA (end of the earth, can't go west into ocean, can't go north to Canada cause border is closed) to eastern Washington where August temps run in the hundreds (love ittttt!!!). Got a steep mountain pass to go over so i know I need better cooling, so will get the B&M cooler installed on Monday. Sure is a tiny little trans cooler the General installs in his tow package.

 

[df2x4]

Just FYI, the Tru-Cool M7B is the exact same product as that B&M cooler (even made by the same company, Long Mfg.) but for half the price. Not sure where you ordered the B&M from but if you can still return it you could order the M7B and save some money.

https://www.amazon.com/Tru-Cool-M7B-ENGINE-OIL-COOLER/dp/B003TQ7WDA

 

[LVJJJ]

Thanks df2x4. too late to reorder, I'm out of time have to get the cooler installed before we leave on August 10th. The B&M supposed to be here Monday. I have to wonder about the Trucool as it doesn't say anything about racing or being pressure tested (although it could be). It's weird but the B&M is 11" x 8" and the Tru-cool is 8" x 11". I think I'm more comfortable with a brand I'm familiar with. The price difference means nothing to me at this point of protecting my transmission for the trip.

 

[L31MaxExpress]

Thanks df2x4. too late to reorder, I'm out of time have to get the cooler installed before we leave on August 10th. The B&M supposed to be here Monday. I have to wonder about the Trucool as it doesn't say anything about racing or being pressure tested (although it could be). It's weird but the B&M is 11" x 8" and the Tru-cool is 8" x 11". I think I'm more comfortable with a brand I'm familiar with. The price difference means nothing to me at this point of protecting my transmission for the trip.

Best protection for your trans and your brakes is to manually downshift to 3rd when you hit the hills or just leave it in 3rd the whole trip.

The 4L60E OD is weak and pulling in OD adds alot of stress to the already stressed clutches and planetaries.

 

[PlayingWithTBI]

Best protection for your trans and your brakes is to manually downshift to 3rd when you hit the hills or just leave it in 3rd the whole trip.

I made the mistake back in '92 with a '90 Ford F250HD Diesel and an E4OD trans towing in 4th gear (only with empty trailers), blew it within around 50K miles. Cost, ~$2500 to repair it. After that I took it out of OD when pulling anything - lasted another 100K before I traded it in. IMO the E4OD was a better built trans than the 4L60E, maybe even the 4L80E at the time? Live and learn, ha ha.

 

[df2x4]

Thanks df2x4. too late to reorder, I'm out of time have to get the cooler installed before we leave on August 10th. The B&M supposed to be here Monday. I have to wonder about the Trucool as it doesn't say anything about racing or being pressure tested (although it could be). It's weird but the B&M is 11" x 8" and the Tru-cool is 8" x 11". I think I'm more comfortable with a brand I'm familiar with. The price difference means nothing to me at this point of protecting my transmission for the trip.

Fair enough regarding the time constraints, but I assure you the B&M 70266 and Tru-Cool M7B are identical products. Like I said earlier they're even both made by Long Mfg. Only difference is the branding on the box.

 

[stutaeng]

Best protection for your trans and your brakes is to manually downshift to 3rd when you hit the hills or just leave it in 3rd the whole trip.

The 4L60E OD is weak and pulling in OD adds alot of stress to the already stressed clutches and planetaries.

Once upon a time I drove my '99 4.3Silverado with 4L60 down to Southern Mexico. There's the Sierra Madre mountains to cross way down there. 2 lane, divided highway with double tandem semi's hauling cement going like 10 kph. Passing those beasts is scary.

Nothing like that in
the States, LOL. About 5 hours of adrenaline for US drivers.

Anyway, my brother gave some tips and told me to "tap" the brakes on the switchbacks. The locals know the technique, but folks from America ride on the brakes and overheat them.

I recall I also downshifted most the mountains going down and that required less braking use. A lot less. I think I stayed in 3rd most of the time.

It worked. No blown transmission or brake fade. Actually, truck has 260k miles and rear brake pads are still original. I just replaced the 3rd set of front brake pads.

 

[LVJJJ]

Welllll, did my usual screwup when installing the new cooler. Bought new quick release clips, didn't seem right but installed them anyway. Got everything tightened up, added a half quart of Dexron VI as the B&M technician told me to do. We live in a gated RV park so its about 700' from our park model to the front gate with a 10 mph speed limit. So I figure I'm going to drive it up to the gate and take it out for a test drive. Get to the gate and it wouldn't move. Turns out one of the clips let loose and I sprayed 5 qts of trans fluid on our roads. Got the 65 Chevy Van out and towed the Burb back home. Went to OReillies and bought two gallons of Dex VI for $60. Found it only needed about 5 qts to bring it back to full. Drove it a little seems to run fine. hope I didn't ruin it, Any chance i might have?

As for driving in 4th, I'm doing that less based on what I've read about the 4L60e weaknesses. So pretty much just drive in 4th on down hills or level with a tailwind. At the slightest uphill do pull it down to 3rd. As for going down mountain passes, keep it in 3rd. The 383 has so much compression hardly need to tap the brakes. Rarely use my brakes, just drive way ahead of myself and use gears instead.

As for the M7B. I think it wouldn't of worked cause it appears to be 8" wide an 11" tall. The B&M is 11" wide and 8" tall and it just barely fit. The M7B would have been too tall.

 

[SUBURBAN5]

My opinion. As long as you didnt run the pump bone dry you should be fine. Just double check your fluid when warmed up. Believe Manuel says once you've driving it around cycle it to every gear for like 2 or 3 seconds P,R,N,D,3,2,1 1,2,3,D,N. once in neutral check your fluid level. Long as level good then do the old fashion walk around, multi point inspection, looks for leaks, loose caps, low levels, Clamps tight, spare inflated, ect. Also 4th or D is only for "lights loads" , mpg. When I tow anything I use 3rd, and baby it. I follow this rule because of the manual, but that's just my 2cents. I haven't personally tried driving straight long roads in D and up or down in 3rd. To tell you if its caused anything. Hopefully somebody can chime in on there experience.

 

[df2x4]

As for the M7B. I think it wouldn't of worked cause it appears to be 8" wide an 11" tall. The B&M is 11" wide and 8" tall and it just barely fit. The M7B would have been too tall.

Like I said, (Twice now, starting to feel like a broken record) they are identical. I'm not sure where you're getting your information from but it's incorrect. They're the same dimensions with the fittings oriented the same way. I have an M7B in my truck and followed SAATR's directions to modify the factory mounting brackets exactly as he wrote them up for the B&M.

Tru-Cool M7B:

You must be registered for see images attach

B&M 70266:

You must be registered for see images attach

The pictures are flipped 180 degrees from each other, but as you can see they're the same profile. Same number of cooling rows as well if you feel like counting them.