Quick question about the canned 87 tow

BigSur · #1 Mon, May 9th, 2011, 07:50 PM

Quick question for you guys. I've been running my canned 87 tow tune a lot lately.....I've really been liking the characteristics of the tune over anything else I've run.

I've started to notice that my 1st to 2nd upshift is very "firm" if I let it ease into gear....vs. if I'm accelerating moderately and/or towing...the shift is easier at higher RPMs. My question is.....is that a problem?...or could it cause any abnormal wear and tear on my tranny/engine? Overall, the periodic firm shift doesn't bother me....I just want to be sure I'm not hurting anything.

Thanks in advance.

***Jackpine*** · #2 Mon, May 9th, 2011, 08:23 PM

Quote:

Originally Posted by BigSur

Quick question for you guys. I've been running my canned 87 tow tune a lot lately.....I've really been liking the characteristics of the tune over anything else I've run.

I've started to notice that my 1st to 2nd upshift is very "firm" if I let it ease into gear....vs. if I'm accelerating moderately and/or towing...the shift is easier at higher RPMs. My question is.....is that a problem?...or could it cause any abnormal wear and tear on my tranny/engine? Overall, the periodic firm shift doesn't bother me....I just want to be sure I'm not hurting anything.

Thanks in advance.

It sounds like maybe the Torque Converter (TC) is locking, maybe just prior to the shift and then, since it's locked when the shift completes, you get a "jerk", since there's no fluid clutch to smooth things out. You could perhaps confirm this by monitoring the "Gear" PID on the Gryphon screen. (It's called "Comm Gear" in the monochrome Gryphon).

If that's the case, there's nothing to worry about at all. I've had it work that way during 2-3 upshifts when towing up a hill. It's a VERY "Hard" shift.

- Jack

BigSur · #3 Tue, May 10th, 2011, 04:03 PM

Quote:

Originally Posted by JackandJanet

It sounds like maybe the Torque Converter (TC) is locking, maybe just prior to the shift and then, since it's locked when the shift completes, you get a "jerk", since there's no fluid clutch to smooth things out. You could perhaps confirm this by monitoring the "Gear" PID on the Gryphon screen. (It's called "Comm Gear" in the monochrome Gryphon).

If that's the case, there's nothing to worry about at all. I've had it work that way during 2-3 upshifts when towing up a hill. It's a VERY "Hard" shift.

- Jack

I checked it out and I'm not seeing any locking going on b/w 1st and 2nd. The only time I'm seeing it lock is after I drop into OD and I'm on the gas. Seems to be pretty random....in most cases, the shift feels fine. It's really a sweet spot where I'm at just the right speed and RPMs and it only happens when I'm VERY slowly accelerating.....e.g. bumper to bumper traffic where I'm having to creep forward 50 ft and then slow back down again...and there's not much room to really accelerate.

Is it normal to see the comm gear advance prior to dropping into the corresponding gear? If I'm accelerating moderately, the interface shows 4th gear at 32 mph.....I don't actually drop into OD until about 40mph, which is when the TC locking occurs.

***Jackpine*** · #4 Tue, May 10th, 2011, 05:30 PM

Quote:

Originally Posted by BigSur

I checked it out and I'm not seeing any locking going on b/w 1st and 2nd. The only time I'm seeing it lock is after I drop into OD and I'm on the gas. Seems to be pretty random....in most cases, the shift feels fine. It's really a sweet spot where I'm at just the right speed and RPMs and it only happens when I'm VERY slowly accelerating.....e.g. bumper to bumper traffic where I'm having to creep forward 50 ft and then slow back down again...and there's not much room to really accelerate.

Is it normal to see the comm gear advance prior to dropping into the corresponding gear? If I'm accelerating moderately, the interface shows 4th gear at 32 mph.....I don't actually drop into OD until about 40mph, which is when the TC locking occurs.

Are you sure it's not shifting at 32? If the TC is unlocked, there will be a "gentler" RPM change than if it is locked. It really sounds to me like the shift is happening at 32 and the the TC locks at 40.

But, I don't know that anything is amiss in your truck. I think you are possibly more "sensitive" to its shifting than I am, and I'm pretty "sensitive" too.

- Jack

BigSur · #5 Tue, May 10th, 2011, 05:42 PM

Quote:

Originally Posted by JackandJanet

Are you sure it's not shifting at 32? If the TC is unlocked, there will be a "gentler" RPM change than if it is locked. It really sounds to me like the shift is happening at 32 and the the TC locks at 40.

But, I don't know that anything is amiss in your truck. I think you are possibly more "sensitive" to its shifting than I am, and I'm pretty "sensitive" too.

- Jack

I don't know....unless I'm missing something. I've always thought my tranny drops into OD (or 4th gear) around 40 mph when accelerating moderately. That is when you physically feel AND hear the truck change gear, as well as you'll see the RPMs drop to about 1000; however, of course that changes if I'm on the gas, which in that case, it drops to OD at a higher speed and RPM. When I was running my custom performance tune....the moderate acceleration shift to OD happened closer to 50 mph.

What I experienced today monitoring the comm gear is that it would change to 4th while in mid-acceleration and know noticeable changes in gear. Once I "heard and felt" the tranny drop into OD at 40 mph....the TC would lock. Is it possible that I'm too INsensitive and my truck is changing gears without me feeling it?

***Jackpine*** · #6 Tue, May 10th, 2011, 07:09 PM

Heck, anything's possible in these subjective kinds of observations.

I don't really have a good reply for you. I would expect though, that the the TC would lock AFTER the shift up had completed in normal shifting, which would reduce strain on the transmission. Likewise, it should unlock BEFORE any downshift.

- Jack

BigSur · #7 Wed, May 11th, 2011, 01:04 PM

Guys.....I've figured it out. Shows how knowledgeable I am abot this stuff

I've been misinterpreting dropping into OD at 40 mph as my shift into 4th gear. Completely different. I think I always believed this to be the case, b/c again, my 3rd to 4th upshift is definitely hard to notice sometimes. Learn something new every day

This brings me back to my original issue of the hard 1 to 2 upshift. It's not the TC locking up. I've had someone tell me that it may be a clutch pack issue b/c they had the same issue with the same year/make/model of truck. With that said...I'm good with it unless something starts to noticeably go wrong.

As always.....thanks very much for the help and support.