8hp70 shifting issue.

[DtheBC]

I have read on many of the tranny posts and not seen anyone mention what mine is doing. When cold every once in a while I get a rough kick in the pants shift when it shifts up through the first few gears. Its when accelerating lightly on flat ground. It seems to shift 1-2-3-2-3 then on up. When it does this the truck bucks and gives a pretty good kick in the pants. After this one time it works perfectly till it cools off. If I get on it pretty good it want do this, nor when warm. I have not cel or mil lights. When it does this weird shift I see the tach go up and down with the bucking when this occurs. I see some posts on shudder but this is more of a bucking hard up down up shift feeling and only in the first few gears. Has anyone experienced something like this?

 

[aces-n-eights]

I'm not sure i can help much, but a couple of questions... How many miles on your truck? Have you had it since new? Is this a new problem?

A "relatively" inexpensive solution is a fluid change - get the pan off and see if there are any alarming bits of metal in there.

Good luck, let us know what you find.

 

[Huliodude]

Might be your torque converter locking too soon and then unlocking, feeling like an upshift and then a downshift. Perhaps try resetting transmission adaptations and see if that helps.

 

[blackbetty14]

When cold I get a weird flare on my first 1-2 shift which results in a jerk on the shift into 2nd. It only does it once and when its dead cold. If yours is actually going 1-2-3-2-3 then you got something else going on. The 8spd has a gear indicator... does it actually show the down and upshifts (put it in manual 8)?

 

[caulk04]

When mine is really cold I get a very firm 1-2 and lockup in 2nd under real light throttle. Has done it for a long time and new (OE) fluid did not make a difference. Bought at 30k, now just over 70k.

I've lately made a habit of hitting the tow/haul button for these first couple shifts.

While still in warranty I asked the dealer if there were and TSB's or tune updates and there weren't any. 'They all do that' was the response, as I expected since it doesn't throw any codes. It's clearly a tune issue IMO.

 

[DtheBC]

Thanks for the replies. The truck has 53000. I have the pan and fluid waiting for a spring pre towing change. Its a weird one for sure and intermittent. I may push and get the fluid change soon to see if anything is in the pan/filter. It’s always when cold, light throttle and level roadway. Going to monitor and will let you all know what or if I find anything. BTW my truck is an express and though I can make it show what gear its set for it doesnt show what gear its in at the time. My wife's charger does that and I wish my truck did.

 

[DtheBC]

Caulk04, What yours does sounds most like what I have experienced. I had an 04 ram Cummins when that TC locked sometimes it felt like the tranny would pop through the floor.

 

[blackbetty14]

Thanks for the replies. The truck has 53000. I have the pan and fluid waiting for a spring pre towing change. Its a weird one for sure and intermittent. I may push and get the fluid change soon to see if anything is in the pan/filter. It’s always when cold, light throttle and level roadway. Going to monitor and will let you all know what or if I find anything. BTW my truck is an express and though I can make it show what gear its set for it doesnt show what gear its in at the time. My wife's charger does that and I wish my truck did.

thats pretty early to be changing the fluid on the 8spd. Understood to do it so see if it helps but to me doesnt sound like a fluid level or quality issue.

 

[TheEnder]

When mine is really cold I get a very firm 1-2 and lockup in 2nd under real light throttle. Has done it for a long time and new (OE) fluid did not make a difference. Bought at 30k, now just over 70k.

I've lately made a habit of hitting the tow/haul button for these first couple shifts.

While still in warranty I asked the dealer if there were and TSB's or tune updates and there weren't any. 'They all do that' was the response, as I expected since it doesn't throw any codes. It's clearly a tune issue IMO.

This is quite normal for the 8HP.

A clutch loses prime overnight, and when you start the vehicle up, there is no longer fluid present in the valve body to apply the clutch and it flares because it’s refilling the hydraulic passage. No damage is done when it flares, it’s considered normal 8HP operation.

My 8HP does this, i have paddle shifters and i just shift it from 1-2 at a stop a few times when cold at a stop and it’s completely fine.

 

[TheEnder]

thats pretty early to be changing the fluid on the 8spd. Understood to do it so see if it helps but to me doesnt sound like a fluid level or quality issue.

It’s a good change interval, they’re recommended to be changed at 60K. I’m at 76 on mine with no issues though. But i need to get it changed soon.

 

[caulk04]

This is quite normal for the 8HP.

A clutch loses prime overnight, and when you start the vehicle up, there is no longer fluid present in the valve body to apply the clutch and it flares because it’s refilling the hydraulic passage. No damage is done when it flares, it’s considered normal 8HP operation.

My 8HP does this, i have paddle shifters and i just shift it from 1-2 at a stop a few times when cold at a stop and it’s completely fine.

This sounds extremely unlikely and implausible to me. Also, is not just one occurrence. It'll do it repeatedly if I stay in stop and go while it's still very cold. Mine doesn't flare either, it just shifts and locks the TC very hard.

 

[blackbetty14]

It’s a good change interval, they’re recommended to be changed at 60K. I’m at 76 on mine with no issues though. But i need to get it changed soon.

I actually think its 100k. It's considered a lifetime fluid to RAM and ZF. https://www.ramforum.com/threads/8hp70-trans-fluid-change.118005/

 

[Wild one]

I actually think its 100k. It's considered a lifetime fluid to RAM and ZF. https://www.ramforum.com/threads/8hp70-trans-fluid-change.118005/

ZF says 60,000 to 80,000 miles or 8 years for a fluid and filter change

 

[DtheBC]

Yes everything I have studied ZF says 60,000 for severe service. I am at 5 years and was waiting till 60 ish. But I may go ahead and change it to see if it help this issue. It is so intermittent it will take time to see. It may do it three days in a row then not for days.

 

[Dusty]

When mine is really cold I get a very firm 1-2 and lockup in 2nd under real light throttle. Has done it for a long time and new (OE) fluid did not make a difference. Bought at 30k, now just over 70k.

I've lately made a habit of hitting the tow/haul button for these first couple shifts.

While still in warranty I asked the dealer if there were and TSB's or tune updates and there weren't any. 'They all do that' was the response, as I expected since it doesn't throw any codes. It's clearly a tune issue IMO.

They ALL do not do that. I'm on my second 8HP and none have exhibited the behavior you describe and no one I know has mentioned any transmission issues, either.

This is the perfect time to connect a diagnostic scanner.

Regards,
Dusty
2019 Ram 1500 Billet Silver Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, factory dual exhaust, 18” wheels. Build date: 3 June 2018. Now at 83507 miles

 

[Dusty]

This is quite normal for the 8HP.

A clutch loses prime overnight, and when you start the vehicle up, there is no longer fluid present in the valve body to apply the clutch and it flares because it’s refilling the hydraulic passage. No damage is done when it flares, it’s considered normal 8HP operation.

My 8HP does this, i have paddle shifters and i just shift it from 1-2 at a stop a few times when cold at a stop and it’s completely fine.

If your tagline is correct, you don't have an 8HP series transmission. The 8HP was not available in Rams until very late 2013, and not with the 4.7 motor.

Regards,
Dusty
2019 Ram 1500 Billet Silver Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, factory dual exhaust, 18” wheels. Build date: 3 June 2018. Now at 83507 miles

 

[ThunderMug95]

@DtheBC when you start up cold, try shifting to D back through N and R, pausing a few seconds in each setting/gear, then put it into whatever selection you need and see if it does it then.

 

[blackbetty14]

Yes everything I have studied ZF says 60,000 for severe service. I am at 5 years and was waiting till 60 ish. But I may go ahead and change it to see if it help this issue. It is so intermittent it will take time to see. It may do it three days in a row then not for days.

That seems brutal... given that the pan and filter are one unit and need to be replaced and then the fluid costs... your looking at $300-500 for a trans fluid change! Plus the annoying 8hp fill process.

 

[joesstripclub]

That seems brutal... given that the pan and filter are one unit and need to be replaced and then the fluid costs... your looking at $300-500 for a trans fluid change! Plus the annoying 8hp fill process.

Did mine for about $60, but yeah OEM stuff will cost you that much. If you have a decent pump setup its a breeze. The sketchiest part to me is running through the gears while on the jack stands then getting back under the truck to top it off.

 

[blackbetty14]

Did mine for about $60, but yeah OEM stuff will cost you that much. If you have a decent pump setup its a breeze. The sketchiest part to me is running through the gears while on the jack stands then getting back under the truck to top it off.

How do you do it for $60? The Pan and filter combo is more than that by itself! Unless your doing the cheap no name ebay brand pan.