any 5.4 v8 equipped w/ 4R75E

[keytothestone]

transmission owners had any issues with their conversions? Especially when changing gear ratios 4.10-4.56 running a lift 4'-6" with 33"-35" tires? any feedback much appreciated !

[Glider]

I did a QuadVan conversion a year ago.
5.4L V8; 4R75E trannie.

Original axle ratio was 3.73; I converted to 4.10.
Lift is about 5".
33" KO2's.

No issues at all; I'm totally happy with the conversion and subsequent performance.

Doing the math:
In my original configuration, the V8 was spinning 1732 RPMs at 60mph, in 4th gear (OD).

Following the conversion, with the 4.11 gear ratio and 32.7" tires, I'm at 1774 RPMs at 60mph--just 42 RPMs more than stock. The engine and trannie do just fine in this configuration.


If I had gone to 4.56 gearing with the same tires, the V8 would be spinning at 1968 RPMs at 60 mph. That motor loves to spin up, so that would not be a problem at all. It would increase available horsepower--but it would also decrease fuel mileage. The tradeoff was not worth it to me. I'm totally happy with what I have.

I didn't run exact numbers for 35" tires, but the following numbers are very close:

4.11 gearing: 60mph = 1657 RPM. That's slower than stock, and would create a horsepower loss. I wouldn't do it.

4.56 gearing: 60mph = 1839 RPM. I suspect that would work, but I do not think it would be as functional a balance as is provided by the 33" tires. I think the 35" tires are going to create a horsepower drain, and the higher RPMs are going to suck more gas. At least for my use case, that's not worth it.

I hope this is helpful.

[keytothestone]

Thanks Glider! I had a coil 6" coil done by u joint 4.56 35" tires bare 2014 50k miles cargo precert by ford but now has a CCV top. P/U early Aug. 3500 miles in Trans started slipping 3rd- 4th. U joint had the Trans rebuilt plus HD torque conv. "to avoid any issues. " and $1800 onmy bill reflected that.Took it to mechanic in Durango that has done some uj kit convers. They dropped the valve body. #5 ball was out of place floating they fixed that said good to go UJ paid the bill! Another 3500 miles down the road exact same slipping happening. It's back there now for the last 10 days. Supposedly dropping Trans today, but have suggested before even dropping a shift kit, or possible another rebuild with heavy duty parts etc which they stated would be 4k! When the van is running properly I love the set up. No issues at rallying up the mtns. Gas sucks but not a concern. If I was going to go total upgrade for that kind of $ I think I would go with a more proven Trans shop like John Wood or BTS. No offense to the mechanic here. I looked studied hard before doing this setup. I haven't heard to many issues with Trans performing and would think places like quad, agile, ujoint wouldn't do them if their were. Thanks again for your feedback.! Just frustrating dealing with this 3 1/2 months in and only 8k on the rebuilt

[mgmetalworks]

Before my '13 came apart it was a 5.4L with the 4R75E. same coil conversion, 35's, 3.73s. Never had any issues with the trans. The one big difference with trans from Glider's van and my van's previous drivetrain is that Quadvan puts an adapter housing on a 2WD trans rather than taking apart the trans to put the 4x4 output shaft in.

Something could have happened during the disassembly or reassembly that is now causing a problem. It is not outside the realm of possibility since that trans is sort of a PITA to go through.

I had 23K on my rig before it came apart for the Cummins swap... never even thought about the original trans. It always acted like it should. I don't think any of the issues you're having are from it now being a 4x4 van.

[Glider]

That sounds really frustrating, keytothestone. Your story leaves me with a few questions:

1. Are the 35" tires just too much for the 4R75 trannie? I don't have an answer for that one; someone else here will have more information on that one.

2. Was the work that has been done, to date, on your trannie, done competently, and did it fully address the underlying issues? In other words, is the problem you are having now a continuation of an original issue that was not completely fixed, or is it something new?

3. Do you just have a lemon trannie?

4. If the 35s are putting extra strain on the R75, is it possible, rather than spending money to rebuild it, to replace it with a 100-series trannie? If I remember right, I think someone on the forum said something about this maybe being a possibility.

Best of luck to you. Good luck!

[carringb]

There's plenty of non-E-Series 4x4 rigs running around with the 4R75 and 35s or bigger.

This definitely smells more of workmanship issue than a capability issues.

[keytothestone]

Yep carringb lots of non E series out there running 35s or bigger! Glider the problem is the exact same issue as the originaland not sure about it being a lemon? But the mechanic now says he doesn't think the van is shifting in any of the gears properly after driving it around a bit. Seems fine to me except for the occasional slippage 3-4. Made it back to Durango from Mexacali when it started. Hopefully Monday they can give me an idea of what they think it is. Since their original fix wasn't it. When it originally started slipping UJ trans guy wanted me to ship the trans back to him in NC. Maybe should of done that? But Chris gave the mechanic here the ok I think because they have a rapport. So agree with MG and carringb probaly something during the original rebuild? If something was a miss with the trans when UJ got their hands on it I would hope they would of brought it to my attention during the conversion. They have been pretty cool about everything and I'm trying to be as well.

[keytothestone]

Just noticed I posted this in the classifieds whoops! So after meeting with the mechanic here in Durango( jeff @ built to last) and, seeing the trans torn apart gotta say he put me at ease. Seems very knowledgeable and a straight shooter. The problem seems very common in Fords. Need a servo pin replacement the over drive band is worn. Could of started wearing prior to conversion or the extra work could of started it. Who knows??? Surprised the original trans guy UJ had rebuild it would of missed it???Thanks again for your alls input!

[BroncoHauler]

Originally Posted by keytothestone

Just noticed I posted this in the classifieds whoops! ...

Move to Engines and Drivetrain.


Herb