[Wutitis101]

I was getting thd p0734 code. Gear mismatch. From what I could find a MAF sensor was the possible culprit. Replaced MAF sensor. Now I still have no fourth gear unless going down hill or no gas. I can feel it slide into 4th but the slightest throttle pressure dumps it into 3rd. Im getting no codes anymore....

Thanks in advance...:

03 discovery

 

[Disco Mike]

How many miles on the engine, when was the last time you service the tranny, when did you last check the fluid level?

 

[Wutitis101]

Checked it this morning and its full. Only 77000 miles on it...mostly highway.

 

[Disco Mike]

When was it lasted serviced and what color was the fluid, crystal red or brownish with a burned smell.

 

[Wutitis101]

Trannys never been serviced. Was thinking at only 77k it didnt need it. Fluid looked ok, guess I will grab a filter and fluid...

 

[Wutitis101]

The strange thing is it shifts through all gears 1-3 smooth, no slippage, strong kickdown etc...

 

[Disco Mike]

If you want some help, answer the damm questions.
734 means your 4th gear is out of ratio and has nothing to do with your first 3 gears.

 

[Wutitis101]

Was trying to give some damn information. I always find that when trying to diagnose a problem its better to have more information then not enough. Like I said its never been serviced. Fluid looks and smells as it should.

 

[Disco Mike]

I missed where you said it has never been serviced. That tranny, as most, needs servicing every 30,000 miles or you will kill it.
So back to your other statement regarding the fluid looking fine, it can't look fine or you just didn't know what fine should look like. It should be a bright crystal red with no brownish coloration or burned smell.
Do you know how to check and or refill that tranny, if so tell me how you do it, want to make sure since it is a sealed unit without a dip stick.
If the fluid is at all brownish, you will need to do 2 drain and refills adding a bottle of Lucas tranny additive on the second refill.
Curious, since you have not been following your maintance book, have you services all the other fluids yet such as the p/s, brake fluid, both diffs and the t/case if not go read my major service list posted at the top of this section and consider doing it all including the front drive shaft.
If you need any help shout.

 

[Wutitis101]

MIke,

I purchased the vehicle back east with 70,000 miles. The prior owner was a physician with all service apparently done at his local LR Dealer. All fluids and maintenance appears to be done with regular oil, tranny fluid change, driveshaft lubes etc done.
I am not a mechanic by trade but have several other vehicles including dodge trucks with over 450,000 miles on original engine and one tranny. A jag with 190000 miles and a low mileage Toyota. ALl run all daily drivers. I have found that manufacturers seem to have quirks on their particular brands. Find those quirks, complete routine and other maintenance when problems arise and things will last a long time.
I do know how to check tranny fluid on a sealed system as Jag uses same system. I do know what tranny fluid should and shouldn't look like.
I was curious if there was a quirk in the LR that I was missing. I didn't mean to piss you off by adding too much information..
I will change the fluid in the tranny and see what happens. Thanks For the help....

 

[Disco Mike]

You didn't piss me off. You need to get that truck current on all it's services before it dies.
Look at my major service list and consider doing it all.

 

[Wutitis101]

Drained tranny replaced filter, filled it, drove it a day, drained again and topped off. When I drained after driving it was still hot. Fluid looked milky and almost bubbly on second drainage. Same symptoms as before.

 

[Disco Mike]

So, was the fluid brownish and have a slight burned smell? When refilling the tranny did you fill it once with the engine off and again with it running for a total of 5 plus quarts?

 

[Wutitis101]

Yes, filled it with engine running, I have burn mark on arm from exhaust to prove it. Still no codes. The tranny will shift into 4th for about the first 10-15 miles being driven then gently downshifts to 3rd and stays in 3rd as its highest gear.

 

[Wutitis101]

I am out of ideas. Guess tranny is shot at 80K...not cool

 

[Disco Mike]

Are you codeless or have something new? Might have a shift solenoid failing.

 

[Wutitis101]

P0734 back again. Will check shift selenoid

 

[Wutitis101]

Found a used tranny. 50k on it and was suppose to have worked before the yard removed it. Put it in this weekend and back to square1. P0734 code no 4th gear. Im at wits end obviously.

 

[Disco Mike]

Test you MAF sensor and make sure it is not starting to fail.

 

[Wutitis101]

The MAF sensor was the first thing changed. Started with aftermarket brand got same code went with new Bosch same code. Returned it thinking it was possibly bad, received a replacement Bosch same issue. When I hook up my scanner, it reads air flow from maf at various pressures as engine rpm and load changes.