I have Superchip installed and when the transmission shifts from 2nd back to 3rd or 4th (4000 rpm back to 2000) I hear something squeal and the shift is very firm. The RPMs drop almost instantly. The truck feels good after the shift. I am not sure if the squeal if from the transmission or the serpentine belt. Anybody experience this and have it corrected? Is this a possible soleniod problem? Or chip programming?

F250 LD 4.6L / Flipchip

 

Hi athearle,

It's supposed to shift firmer at heavy throttle, like 4000 rpm and up, that's normal. On light throttle, when you're driving conservatively, the shifts are still smooth and fluid, and then as you give it progressively more throttle, the upshifts firm up progressively in response, just like they should. It's never a "tire-chirping" kind of hard upshift in that vehicle, and the actual increase in line pressure is very small. The heavy-throttle upshifts should feel firmer than stock, but as to "very firm", that's really too subjective to determine if it's shifting harder than it should. It's going to be noticeably firmer than stock, but not bounce your head off the glass or chirp the tires on that particular truck.

It sounds like your squealing is most likely a serpentine belt slipping, so you should check your belt(s) and also check the tensioners, to make sure they are taking up all the slack in the belt like they should, as your belt wears & stretches. If your tensioners are worn, then you'll get belt squeal like that until it's corrected. This can easily happen when you install the Superchip on a vehicle with worn tensioners.

It is possible that it is a shift solenoid problem, as Ford's shift solenoids are prone to wear and failure, which is why we do not spike the line voltage going to them like for example, the B&M shift improver does.

The Superchip does raise line pressure, but it is a very small amount, less than 20% in that vehicle, which is not nearly enough to cause any transmission problems, in fact, the transmission would have to be mechanically modified before it's capable of producing enough line pressure to cause any kind of "problems"; the friction materials will actually last longer in any automatic transmission with the Superchip, all else being equal, due to reduced slippage.

If you like, please feel free to give us a call and we'll go over this with you.

------------------
Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Event Organizer

[This message has been edited by Superchips_Distributor (edited 11-13-2000).]

 

Hi Mike,

For now I will attribute this to belt tensioners. I bought this truck used (97 F-250 4.6) and seems to have been well used (4.6 cracked cylinder head under ENGINES). I just got done putting a new head on the drivers side so it does not surprise me that other repairs need to be done. I do notice a tendency to move towards the windshield but no tire squealing shifts I like the overall quality of the shifts so I'm not going to point my finger at the transmission. Thanks very much for the information.

 

Hi athearle,

I like your phrase, "well used".

Good luck!

------------------
Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Event Organizer