Engine Braking? Alpha owners chime in!

[adventr]

I've noticed that my H3 really doesn't have any "engine braking". What I'm referring to, is when you're descending a hill, and you manually downshift the transmission to a lower gear. Typically, the engine will rev up, and you can feel the vehicle hold back to some degree.

My H3 does not do that. I can manually put it in a lower gear, and it just continues to move along, with the engine rpm staying very low.



Other than that, I have no obvious transmission issues. Shifts great, holds gears fine, downshifts fine, converter feels nice and tight upon takeoff...ect.


Just wondering if this is normal behavior for the Alphas, or if I need to look into transmission issues?


Thanks!

 

[abearden]

Can't speak to the H3, but some torque converters allow that for higher gas mileage. My truck (6.5td and 4L80E) does the same thing.

 

[USMC_315]

How do you manually downshift your three? I have an Alpha myself but don't know of this feature

If you do have this feature on your Championship and the rpms aren't going up when you down shift, I would definitely look into that because the transmission is obviously not down shifting manually

 

[Scarsman]

You just shft it to 3, 2, or 1 instead of D. The transmission won't shift above whatever gear you have the selector in. In D it shifts up and down through all of them. If you have it in 2, it will not go into third. Or in 3, it won't shift into overdrive.

 

[SedonaBound]

I shift into 3 frequently going down a long grade where the local cops love to set up radar. I get solid engine braking.

 

[High Five H2]

I do it all the time. works for me.

 

[adventr]

Ok, I need to do some more testing on the drive home this evening.


Can you guys that have responded, check and see if you can also downshift from 3-2 (when going slow enough to do so) and it provide the same engine braking?



The whole reason that this stuck out to me, was when I was going down a pretty steep hill that had a stop sign at the bottom. In other vehicles, I just drop the shifter down into 1st, and let the engine do most of the work to hold me back. On the H3, I did that, and it just basically free-wheeled. The engine never rose above idle.

I know that the shifter is physically in 1st gear, because when I leave it in 1st and take off, it won't shift into 2nd without me moving the gear selector.



Worst case scenario I guess, is that the trans is due for replacement. But it shows no other symptoms of being hurt. Fluid is clean, smells fine...ect.

 

[3rdH3]

There may be a failsafe in case you downshift when you are going too fast. My Alpha holds back as the other posters have stated. Good Luck

 

[SedonaBound]

If your up-shifting normally and have no other driving issues, I'd suspect an electronics problem in the trans (the 4L60 is electronic-control); maybe one of the solenoids.

 

[RamRod]

Mine down shifts for me when ever I move it through the gears... what year and edition is your Alpha?

 

[Scarsman]

There may be a failsafe in case you downshift when you are going too fast. My Alpha holds back as the other posters have stated. Good Luck

This is true. If you are still going too fast it won't shift into first until it thinks it is safe to do so.

 

[CaseyS]

I'll have to review my service manual but when in 3,2 or 1 I think it's the overrun clutches that are engaged to not allow power off coast like when in D. If you accelerate from a stop in 2, to say 30 mph and let off, does it coast or stay locked and engine brake down when you let off?

 

[adventr]

Ok, drove it home from the office and did some testing.
When cruising along in 4th, I can manually move the shifter to 3rd gear, and the transmission will downshift, engine will Rev up, and I can even feel the torque converter lock up. This works great, and provides nice engine braking.
Nothing wrong there.

When I do the same from 3rd gear to 2nd (at a lower speed of course), the transmission does downshift, then a couple seconds later I can feel the transmission go into a free wheeling mode. Where basically the engine rpms drop down to near idle, and there is no engine braking.
Same results on 2nd to 1st manual shift.

It really does feel like a programming failsafe, so that makes sense.
I'm just used to my landcruiser, that would downshift into 2nd and 1st and completely hold the vehicle back.
Makes me think that GM did this to make it smoother and maybe easier on the trans.


So, based on that more accurate description, does that behavior match up to what you all experience?

I can make a YouTube video to demonstrate if it will help.
Thanks!

 

[Ghostbuster]

I just tested mine... I did 4-3 then 3-2 and it worked like it should. But the engine braking was not as noticeable while doing the 3-2. Probably due to speed, but you could see the rpms go up and feel the engine braking occur. It in no way shape or form dropped down to idle rpms...

 

[adventr]

I just tested mine... I did 4-3 then 3-2 and it worked like it should. But the engine braking was not as noticeable while doing the 3-2. Probably due to speed, but you could see the rpms go up and feel the engine braking occur. It in no way shape or form dropped down to idle rpms...

Hmmm, that's what I would expect to happen. Thanks for checking.

I wonder what's wrong with mine...


Called local transmission shop and explained. Guy said some transmissions have a bypass that opens up and allows coasting like that. Said everything sounds normal, but if it was bothering me that I could bring it by and he would scan transmission codes.

 

[Ghostbuster]

Hmmm, that's what I would expect to happen. Thanks for checking.

I wonder what's wrong with mine...


Called local transmission shop and explained. Guy said some transmissions have a bypass that opens up and allows coasting like that. Said everything sounds normal, but if it was bothering me that I could bring it by and he would scan transmission codes.

I wouldn't really worry about it, unless its shifting bad or something. Didn't you recently do a tune on the motor? Could that have done anything to it? Also... how do you like that tune?

 

[adventr]

I wouldn't really worry about it, unless its shifting bad or something. Didn't you recently do a tune on the motor? Could that have done anything to it? Also... how do you like that tune?

Yeah, now that I know that it does provide engine braking in 3rd gear, I'm much more content and less worried. I plan to travel up in the mountains this summer, and being able to use 3rd going down some of those passes is a good thing.
Literally no other issues other than what I was describing. I took it by a buddy's shop this evening, and he said everything was fine. Hooked his Autel up to the OBD port, and scanned 4 modules. None had any stored or pending codes.


I did recently put the Superchips 2865 on this thing. It did change the shift points a little bit, and it now downshifts with less throttle, but it didn't have anything to do with the issue I was describing. It did that before the Superchips.

Regarding the programmer, I love it. Really wakes up the H3 on the bottom end. It firms up the shifts a little bit, holds the gears a little longer, and gives more power. I've only tried the 87 octane tune, but it does offer a Towing tune that I might try to see what all that one does.
I snagged the 2865 (complete with manual and USB cable in original box) for $100 off Craigslist. WELL worth that investment!

 

[SuperBuickGuy]

I downshift to second pretty much every day to maintain braking in a 30 mph zone... freewheeling isn't right.

 

[adventr]

Hmmm.... So what do I do in this situation....


Replacing the transmission isn't terribly expensive, but is a lot of work for just that single issue.
Is there any way this can be diagnosed for certain I wonder? With no codes showing, I'm not sure how one would go about that without tearing down the transmission.


Wish it would just blow up if it's going to have any issues! At least then I'd know for sure that it needed to be replaced. Lol

 

[SedonaBound]

Hmmm.... So what do I do in this situation....

You should get engine braking in lower gears when you manually downshift. If you aren't, one of the trans solenoids may not be working right or the over-run clutch maybe gone. The 4L60 has been in GM cars and trucks for 20+ years and a good trans tech should know it inside and out, and be able to diagnose it pretty quick.

 

[USMC_315]

You just shft it to 3, 2, or 1 instead of D. The transmission won't shift above whatever gear you have the selector in. In D it shifts up and down through all of them. If you have it in 2, it will not go into third. Or in 3, it won't shift into overdrive.

Can't believe I didn't think of that, guess I'm still in the sports car mindset of using tiptronic and my paddle shifters haha

 

[Scarsman]

Flappy paddle gearboxes!

 

[Sennin]

to be honest I experienced the same on my 3.7 Adventure as well as my V8, and as im so used to driving dtick this side, it always worried me, so as soon as I got the V8 I ordered the HP Tuner software and played with the settings and saw that the torque converter actually opens up when throttle is released to enable coasting, I changed this to keep it locked and thus induce engine braking. This hels me alot when I'm towing my offroad caravan.

and yes I did a comparison between the Alpha and se SA build V* and the only parameters that were different was the additional fans we have and their switching settings. rest is 100% the same

 

[adventr]

Ok Guys, thanks for all of the replies.


I made another observation last night, and this one is a pretty big deal to me, so I'm definitely having it checked out this week. Either it is something easy to replace like a solenoid, or I'll be ordering a new trans from GM.


At my office, we have a pretty steep loading ramp. It's probably 30 degrees of angle or so.

I put the h3 in 4low (4:1), and then the transmission manually in 1st gear.
Result was that it just idled right up the loading ramp with no problem.

I then put the transmission in reverse, and it slowly idled back down the ramp at the same speed as it went up.
Perfect.


Then, I turned the h3 around, and tried it the opposite direction.

I put the transmission in reverse, and it idled right up the loading ramp with no problem.

Once at the top of the ramp, I manually put the trans in 1st gear, and the result was that it coasted down the ramp just like the transmission was in neutral....
Now that sure won't work for wheeling this summer.....

So... It will be going to the shop this week. Curious to see what the problem is.
Have searched and searched for any threads on the same issue with no results.

 

[Sennin]

Ok Guys, thanks for all of the replies.


I made another observation last night, and this one is a pretty big deal to me, so I'm definitely having it checked out this week. Either it is something easy to replace like a solenoid, or I'll be ordering a new trans from GM.


At my office, we have a pretty steep loading ramp. It's probably 30 degrees of angle or so.

I put the h3 in 4low (4:1), and then the transmission manually in 1st gear.
Result was that it just idled right up the loading ramp with no problem.

I then put the transmission in reverse, and it slowly idled back down the ramp at the same speed as it went up.
Perfect.


Then, I turned the h3 around, and tried it the opposite direction.

I put the transmission in reverse, and it idled right up the loading ramp with no problem.

Once at the top of the ramp, I manually put the trans in 1st gear, and the result was that it coasted down the ramp just like the transmission was in neutral....
Now that sure won't work for wheeling this summer.....

So... It will be going to the shop this week. Curious to see what the problem is.
Have searched and searched for any threads on the same issue with no results.

Ouch, that definately isnt normal. hope its a quick and easy fix