Topic: Anyone have 4.88s, 35s and an auto tranny?

[paultyler]

As you can guess I have a 4 banger with 4.88s and 35s. I am considering swapping in an automatic transmission but I am concerned about that engine and those tires with an auto on the highway. If you have this set up, can you tell me how it does on the highway? Thanks.

[FourbangerYJ]

Welcome aboard Paul, it's about time! Sorry I don't run a auto, just want to say welcome...(keep the stick) I know you have had problems with the AX5 but I like the sticks.

[Bounty Hunter]

What are you concerns?

4.88 is a bit tall for 35" tires behind the 4banger, so I would think they would be just right with an automatic.  Automatics do fine with a bit taller axle gear than a comparable 5spd.

[Jesse-James]

I run 35's with the auto and 4.56's. Almost enough, I think 4.88's would be perfect.

[paultyler]

I run 35's with the auto and 4.56's. Almost enough, I think 4.88's would be perfect.

My concern is that with a stick I have to switch between 4th and 5th a lot depending on the incline.  Since an auto has fewer gears and has different shift points I am afraid that the thing will constantly be shifting as well.  What tranny do you have?

Offroad it will be perfect...but I want to make sure the highway ride doesn't suffer.  I mean....its not like our 4 bangers have any extra power...

Welcome aboard Paul, it's about time! Sorry I don't run a auto, just want to say welcome...(keep the stick) I know you have had problems with the AX5 but I like the sticks.

Thanks!

[Jesse-James]

TF909, I'm told the 904 was the only one they used in 95 but I know it has a lockup converter which means it has to be a 909. Accelerating is slower than the manuals but manually shifting on the on ramp does pretty good. On hills the TC lockup goes in/out to bring the RPM's up just like you'd have to do with the manual but it stays in third, and lockup always happens too early (but I think that's just an issue with mine). I would like to swap in an AW4 eventually, but I'll never give up having an auto.

[paultyler]

TF909, I'm told the 904 was the only one they used in 95 but I know it has a lockup converter which means it has to be a 909. Accelerating is slower than the manuals but manually shifting on the on ramp does pretty good. On hills the TC lockup goes in/out to bring the RPM's up just like you'd have to do with the manual but it stays in third, and lockup always happens too early (but I think that's just an issue with mine). I would like to swap in an AW4 eventually, but I'll never give up having an auto.

So I hear you telling me it works fine.  I appreciate it!  Thanks.

[Jesse-James]

Pretty much sums it up! 

[Jeffy]

I think it will be fine as well.  Since you don't have 5th, I think it will work out.  I'm running 4.56's and 35's and I'm having to downshift from 5th a lot.  I could stay in 4th though.  I think I'm doing 60-65mph around 27-2900RPM's, I think 4.88's will being that up 200RPM which should be prefect.

Run this applet and see what you come up with.  http://www.jeeptech.com/javaAps/gta.html

[paultyler]

I think it will be fine as well.  Since you don't have 5th, I think it will work out.  I'm running 4.56's and 35's and I'm having to downshift from 5th a lot.  I could stay in 4th though.  I think I'm doing 60-65mph around 27-2900RPM's, I think 4.88's will being that up 200RPM which should be prefect.

Run this applet and see what you come up with.  http://www.jeeptech.com/javaAps/gta.html

I don have 5th as it currently is, but a slight incline makes me down shift...that or a 1 mph headwind.

[Jeffy]

I don have 5th as it currently is, but a slight incline makes me down shift...that or a 1 mph headwind.

Oh, you have a manual now, I see.  Well for a manual, you really need 5.38:1 gears which means new axles.  Or you could just drive around in 4th all the time.  Really though 5th is an OD gear and not meant to me a passing gear.

[jagular7]

I'm running a 2.5l, 3-sp auto, 4.88 with 35's. Everything in engine and trans is stock 97 Wrangler SE. The auto does ok for the street, but it is not an accelerator by any means. I manually shift to gain the rpm range for the next gear. At 70mph, I'm pushing 3300rpms. Stock was 3100rpms or so, IIRC. Highway slopes and hills, head wind, etc all have a negative effect on the speed and acceleration of the TJ. I like my auto for the trailriding, but it does have it limitations for street performance. It will shift at 3500rpm max with throttle stuck to the floor. I think that is not acceptable for an engine with high rpm ranges.
My setup now has 141k miles on it. I bought it 5-6yrs ago with 112k miles. It was mod'd at 115k with 34's and now runs 35's.

[jeepyj95]

i have the 95 with the auto running 31's and 3.73. i'm going to 33s and 4.88s this summer hopefully so that should be the perfect combo. right now i'm running 70 pmh @ about 2800-2950 rpms i hit 3000 rpms going 74 mph

[paultyler]

I'm running a 2.5l, 3-sp auto, 4.88 with 35's. Everything in engine and trans is stock 97 Wrangler SE. The auto does ok for the street, but it is not an accelerator by any means. I manually shift to gain the rpm range for the next gear. At 70mph, I'm pushing 3300rpms. Stock was 3100rpms or so, IIRC. Highway slopes and hills, head wind, etc all have a negative effect on the speed and acceleration of the TJ. I like my auto for the trailriding, but it does have it limitations for street performance. It will shift at 3500rpm max with throttle stuck to the floor. I think that is not acceptable for an engine with high rpm ranges.
My setup now has 141k miles on it. I bought it 5-6yrs ago with 112k miles. It was mod'd at 115k with 34's and now runs 35's.

Excellent info.   That is exactly what I wanted to know.  I hate to have high RPMs.

[pioneer4x4]

i dont know man ive got an 86 xj, 3spd auto, 31's , 4.56's and im hitting 3k @ 60 mph ive been saving up to swap a manual in cause i do a lot of hwy driving now that im away at college and dont like running that high rpms for hrs on end, plus its a dog from stop to start.