Question about 1999 GMC Sierra 3500

1 Answer

98 gmc 3500 6.5 diesel - no or slow throttle response in reverse when warm,truck empty and under load,in forward sometimes. with rebuilt trans a year ago. have one code for #6injector out balance and vss out of range. checked and cleaned all grounds found and connects at trans

Posted by on


1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.

    Vice President:

    An expert whose answer got voted for 100 times.

  • Expert
  • 693 Answers

I would check your throttle control valve. good luck.

Posted on Mar 26, 2011


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

2015 ram 3500 trans desengages at 25 mph 2500 rpms reverse and slow speeds forward under load all normal .

This transmission is computer controlled, what needs to be done first is to have the TCM (transmission control computer) scanned for fault codes, if no are present in memory then transmission is likely defective mechanically.

Nov 25, 2016 | 2015 RAM 3500

1 Answer

I have a 1999 Chevy 2500 he diesel and over drive pops in and it will not shift from first

Automatic trans having overdrive issues - Diesel Bombers > ... > 12 Valve 2nd Gen Dodge Cummins 94-98

Apr 22, 2011 - '96 dodge 2500 transmission is having trouble staying in overdrive. ... Hetold me it could be the Throttle Position Sensor, the computer needs ... Oh and another thing, The brake safety for shifting out of park is .... 95 chevy 3500 6.5l trans issues, drgracen, Chevy/GMC 6.2L and 6.5L, 1, 10-05-2015 10:13 PM.

Keeps Jumping in and out of overdrive

Mar 25, 2012

4l80 no overdrive or reverse

Mar 10, 2012

4l80E overdrive problems

Dec 10, 2011

More results from

The most ridiculous Overdrive questions - Diesel Place : Chevrole

Dec 02, 2015 | Cars & Trucks

2 Answers

I have a 1988 5.7 gmc that after start up idles fine runs stromg under full throttle but at highway speed and under no load speed it sputters and at slow speed it is running rich i have done complete...

I have a 1988 5.7 gmc that after start up idles fine runs strong under full throttle but at highway speed and under no load speed it sputters and at slow speed it is running rich i have done complete tune up rebuilt the tbi One concern i have is someone removed stock air cleaner system and the one they installed has no intake air sensor could this be the problem ?
IT CERTAINLY CAN BE THE PROBLEM. The air flow sensor if a VITAL part of your fuel delivery and emmision's system. Your mixture is controlled by a computer that uses the sensor data from that device. If you possibly can get the old one, put it back on. It is possible that I may not be totally right about this point but the operation of your engine is dependent on all the parts being there.
and also i have no codes and no ck engine light on.
There may not be code for a missing part. That system is not perfect.
I hope this helps,
Happy New Year,

Jan 03, 2011 | 1988 GMC C1500

1 Answer

2005 ford 4x4 6.0 ltr. diesel-5r110w trans.

We have a 2005 Ford 350 with a 6.0 engine that only makes 4 MPG . What sugestions Please >

Jul 28, 2010 | 2005 Ford F 350 Super Duty

1 Answer

1997 dodge ram 3500, it shudders in OD

Hey, I also have a 98 ram with the cummins and what you are talking about is when you are pullin hard in overdrive the trans is working to hard causing the shudder, when this happens back off the throttle and get back on the throttle to allow the trans to downshift. If you dont it will break the overdrive gear. There is nothing wrong with the trans it is just that it is shifting to early and bogging down causing the shudder.

May 18, 2010 | 1997 Dodge Ram 3500 Club Cab

1 Answer


No it could be a bad TPS or EPC valve.
Check TPS (throttle position sensor) for smooth and linear electrical response over the entire range of motion. If the response is jumpy or erratic at all, replace TPS. If not, your EPC (Electronic Pressure Control) solenoid failed or has a dirty screen. Easy fix in pan. Fix as soon as possible or hard parts will eventually break.
Before guessing at transmission problems, check the fluid level (car warmed up, engine running in Park on level ground) and have the PCM scanned for trouble codes FIRST.
Secondly, put a line pressure gauge (or visit a local trans shop) on the pressure test port and go for a drive to verify proper line pressure. Base pressure at idle in P,N,OD should be around 70psi and around 140psi in R. Max line pressure should be at least 190psi at WOT in 1st or 2nd, 225psi is optimum. If base pressure is low, trans or pump is worn out. If max pressure is low, check EPC solenoid. If reverse is slow to engage, and line pressure does not come up to at least 130psi in reverse, replace the boost valve with a Transgo 0.500" boost valve (easy fix in pan).
Thank you for using Fixya and good luck. Keep me posted, be glad to help you get your truck running 100% again soon.

Mar 20, 2010 | 1997 GMC Sierra

1 Answer

98 GMC , Reverse slips

Hi there.This is a common problem with these trans.Its the forward clutches that good bad.First and reverse are together in the same pack The reason it slips when its warmed up is that the fluid is thicker and wont slip by the clutches until it is warmed up.A good way to check this is to look at the dip stick and if it has blackish gray cooler stuff on it it is for sure the clutches.Also if your at a stand still with the truck and in drive if you punch the gas does the rpms race up.The a good indication the the trans is going bad.I hope this helps you and Have A Great Day.

I’m happy to assist further over the phone at

Apr 01, 2009 | 1998 GMC Sierra

3 Answers

No reverse after rebuild on 4L60E Transmission from 1995 GMC Sono

There isn't a modulator on this trans as it is electronic

You can have first gear going forwrd but no reverse. It is possible. The low/ reverse clutch isn't needed to go forward.

Jan 19, 2009 | 1995 GMC Sonoma

1 Answer

Rebuilt the Trans.(4L60E) in my 1995 GMC Sonoma PU and after installing it I have no reverse? What went wrong? all forward gears work fine. Also seems like there is a slight whining noise in forward...

did you do the rebuild or did a shop do it? it sounds like the clutches werernt done properly. if the reverse is out the other gears will go out too if driven too far in that condition,

Jan 19, 2009 | GMC Sonoma Cars & Trucks

2 Answers

Truck just shuts off

I own the same 3500 GMC 6.5 diesel truck with the same problem. We replaced the brain under the upper turbo hood and it fixed it pronto. No more shutoffs

Dec 07, 2008 | 2000 GMC Sierra 3500

Not finding what you are looking for?
Cars & Trucks Logo

Related Topics:

400 people viewed this question

Ask a Question

Usually answered in minutes!

Top GMC Experts


Level 3 Expert

80637 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22326 Answers

Ronny Bennett Sr.
Ronny Bennett Sr.

Level 3 Expert

6927 Answers

Are you a GMC Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides